Diary Of An ADI

A Driving Instructor's Blog

I originally wrote this in 2011, and updated it in 2013, then again in 2021.

There seems to be a lot of confusion over how to turn right at crossroads when another vehicle is turning right from the opposite direction.

Driving: The Essential Skills (TES) – that’s the official DSA guide to driving – says the following:

Turning right when an oncoming vehicle is also turning right

When two vehicles approaching from opposite directions both want to turn right, there are two methods that can be used. Either method is acceptable, but will usually be determined by

  • the layout of the crossroads
  • what course the other driver decides to take
  • road markings

Turning offside to offside

The advantage of this method is that both can see oncoming traffic.

In congested traffic conditions, leave a space for approaching traffic to turn right.

Turning nearside to nearside

This method is less safe because the view of oncoming vehicles isn’t clear. Watch out for oncoming traffic hidden by larger vehicles. Motorcyclists and cyclists are particularly vulnerable, as they would be hidden by any type of vehicle.

Be ready to stop for oncoming vehicles.

Police control or road markings sometimes make this method compulsory.

Defensive driving

Try to make eye contact with the driver of the approaching vehicle to determine which course is best. Your speed should allow you to stop if the other driver pulls out across your path.

What is the difference between nearside to nearside and offside to offside turning? Well, the nearside of the car is the one nearest the kerb, and the offside is the one farthest away from the kerb (the driver’s side). So, the two methods look like this:Crossroads - Turning Right

With offside to offside turning, the two cars go round the back of each other (with their offsides closest). As a result, both can see clearly down the road and both can see if it’s clear to turn or not.

Nearside to nearside turning (with their nearsides closest) creates a large blind spot (coloured purple here), the size of which is governed by the size and proximity of the other vehicle. You cannot see easily down the length of the road, and neither can the driver of the other vehicle.

As TES says, either method is perfectly acceptable.

Another thing to remember is that every junction is different and rarely will you find one that corresponds exactly with the schematic layout I’ve shown above.Crossroads in Mapperley

Let’s look at some real examples. The junction above is in Mapperley, Nottingham. It has clear road markings to guide drivers offside to offside – but since the junction is staggered, offside to offside is what any decent driver would want to do  anyway.Crossroads in Ruddington

This one is in Ruddington, Nottingham. It is marked for nearside to nearside turning because the volume of traffic turning right from both side roads would cause gridlock if people attempted offside to offside. Crossroads in West Bridgford

Finally, this example is from West Bridgford, Nottingham. When turning right from the main road, offside to offside appears to be the best option. In reality, there isn’t enough space and what usually happens is that oncoming traffic either steals the priority and turns in front of you – in which case you just hang back and let them get on with it – or it flashes its lights and you take priority (after making sure they flashed at you, and not one of the vehicles waiting in the side roads), and turn in front of it.  This is simply the kind of thing you have to learn to deal with.

This is an important learning point: learn from roads you drive on regularly, and modify your behaviour accordingly. If you’re unsure about being able to turn, hang back and give way – then the problem usually goes away!

If you’re turning right from either of the side roads in these examples, and someone is doing the same opposite you, who has right of way? Officially, no one does, and the main road is too narrow for either offside to offside or nearside to nearside turning. Some people out there (including some ADIs) would have you and the other driver sit looking at each other until you both keel over from exhaustion. In the real world – if eye contact doesn’t achieve anything – someone will either just force their way out (and the problem goes away) or flash their lights to tell you to go. The unwritten rule tends to be whoever gets there first is given right of way – but you can’t assume that under any circumstances, since there are plenty of arrogant drivers who will do their level best to go whether you’re there or not.

Remember that the Highway Code says you shouldn’t beckon other drivers and road users. It doesn’t say you shouldn’t communicate with them. It mentions eye contact… but what then? Smile? Wink? Nod your head? A simple hand gesture with a flat palm, as if to say “well, what would you like to do?” is NOT beckoning.

What happens when both cars are turning right at crossroads?

Neither car has priority. The options available to you are to turn nearside-to-nearside or offside-to-offside, as explained above. However, in some cases there will be insufficient room for both cars to go at the same time and priority has to be given (not taken).

When you reach the junction, make eye contact with the other driver. It isn’t a contest, so be prepared to give way – you haven’t lost anything by waiting for a few seconds while he gets out of the way. Obviously, if he gives way to you sing some sort of signal then you should check that it’s safe and proceed.

Can you flash your headlights?

Some people out there will be having kittens at reading this, but many other drivers WILL flash their headlights to tell you they are giving way. It’s your responsibility to check there is no traffic coming from your right or left (or from ahead), and that they’re flashing at you, but you can then proceed. If someone is giving you a reasonably clear signal that they’re giving priority to you, only a fool would ignore it. And you don’t have to stretch your imagination very far to work out how this could cut both ways.

Can you wave people through?

Holding your palms out and shrugging as if to say “well, what are you going to do?” is not the same as waving madly to beckon people out. I certainly wouldn’t do the latter, but the former is perfectly acceptable. In most cases, you won’t have to worry, though. The majority of drivers are generally quite arrogant and will try to take the advantage anyway, and that sorts out the problem for you. Even a small hesitation on your part is often signal enough for them to go.

But should you do this on your test?

The short answer is no, don’t flash your headlights or gesture to people on your test. As a learner/new driver you may not be very good at it and it could easily go wrong. However, it is possible that a situation could arise where the only sensible thing to do is to flash your headlights or gesture to someone – even to beckon them.

You have to assess, be confident… and be safe.

Pupils don’t understand what offside and nearside mean.

Then educate them! It’s what they’re paying you for.

Offside to offside turning is stupid – people don’t do it.

No it isn’t, and yes they do. Sometimes it is the best option. Sometimes it is road marked that you should do it. If people don’t do it when it is clearly the best (or the marked) option then they are the stupid ones. As TES says: either method is acceptable.

Marked crossroads are invariably nearside-to-nearside anyway.

No they aren’t! Just because you’ve never seen one doesn’t mean they don’t exist. There are at least two in Nottingham which are included in test routes.

This comment was picked up from a forum which was visiting this article at the time it was originally published, and it is simply untrue. As I’ve made clear, either method is acceptable and which one you use depends on:

  • the junction involved
  • road markings
  • road layout (i.e. is it symmetrical or slightly skewed/staggered?)
  • the time of day (i.e. how busy is it?)
  • what other road users are doing (rightly or wrongly)

Offside to offside is unquestionably the safest method wherever it is possible to use it. Blindly trying to do nearside to nearside without understanding what you’re doing often means cutting corners, forcing others to stop or slow down, and taking needless risks. It points to ignorance of road rules and poor attitude.

Why should you check your mirrors when turning right?

One word: cyclists!

You ought to do a quick shoulder check, as well, just to be on the safe side. Trust me, not that long ago I saw a cyclist race up to a car which was turning right into Netherfield near the Colwick test centre, and turn right on his offside just as the car moved off. I’ve also seen them go round the nearside and do it.

To be fair, it isn’t just cyclists (though it is mainly them who are the problem). Motorcyclists (especially mopeds, which are just powered bicycles when you consider the idiots who usually ride them) will do it, and I’ve even had a van overtake (on the offside) when turning into a side road (I reported him to the police).

Who has priority at crossroads?

The short answer is no one does. That’s because you can never be completely certain what others are going to do, so even if there was a rule which said you had priority, and no matter how many road markings there are, there are far too many people out there who simply wouldn’t follow that rule.

However, as a general rule for yourself, assume that if you are going to cross the path of anyone else, then you don’t have any sort of ‘priority’. In other words, if you are turning right at a crossroads, and someone on the opposite side wants to turn to their left or go straight ahead (and they might not be signalling even if they’re going left or right), don’t take any risks and just let them get on with it.

Make eye contact with the other driver. They may indicate with a gesture that they are allowing you to have priority – priority can be given, but never taken or assumed.

Driving: The Essential Skills (TES) says:

  • if you’re turning right and the other vehicle is going ahead or turning left, you should normally wait for the other vehicle to clear the junction before you make your turn. Otherwise, you’d be cutting across their path

People come up with all sorts of ‘what if’ scenarios for this situation, but the simple answer is not to take risks, and not to assume other people are good drivers. For the sake of a few seconds, it is a minor inconvenience at most. Just give them priority (or let them assume they have it). That way, you are driving defensively even if they aren’t.


I’ve moved this to the top, because I have a resident! A Great Tit – and I’m certain it’s the same one who – after his first visit, followed by his second longer one – has chosen it as a place to roost now Autumn is setting in. For anyone following this, he tends to arrive between 6.00pm and 6.20pm at the moment (though he flopped in at 5.40pm one evening). After his initial visits at 9.00am on two consecutive days, he’s roosted there every night since, so he clearly likes it. He wakes up and leaves around 7.00am each morning.

When he arrives, he spends several minutes searching for insects in the cavities (on one occasion, he got something with legs between his beak and ate it, so I now know that’s what he’s doing).  I also think that’s why he jumps up to (and above) the camera, – he’s after the insects, because the birdbox has open vents at the top as well as the bottom, so bugs are going to go inside quite readily.

This is the live feed/live streaming from my birdbox camera. It’s on the back of the garden shed facing east, and about 2m from the ground.

The camera is Wi-Fi. It worked seamlessly when I was setting it all up in the house, but when I moved it to the end of the garden the signal strength meant that the connection was intermittent. I tried a Wi-Fi extender, which improved things somewhat, but the real issue was (I think) with my Virgin Media router. I discovered that the Superhub 3 has a known issue with Wi-Fi, resulting in dropouts even if the signal is good – and that tied in with the issues I’d had for a while with my smartphone, where the connection dropped even with a good signal. So I went for a different solution.

I used a TP-Link EAP 225 outdoor wireless access point (WAP). This takes control of the Wi-Fi aspect, so the router’s Wi-FI is irrelevant. I can now get maximum wireless right to the end of our garden, which is about 50m long, and no stupid dropouts. It’s just a constant strong signal.

At the moment, the WAP is propped up indoors near a window. Next job is to drill holes in the wall to mount it outside where it is supposed to be. Since the WAP is powered directly from the ethernet (PoE) I’ve got to get an ethernet cable and plug through the wall, so that means a 16mm hole. I have a 16mm bit, and it is 300mm in length. I’m not looking forward to the next part, but I’m steeling myself for it.

Incidentally, during the day the BirdCam is in full colour. At night, when the sensor detects low light, it turns off the internal LED lamp and switches to infrared, which renders in black and white. Around the time when that switch is made, the feed becomes jittery while the software makes up its mind.

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It might be the same bird as the first time, but this time he stayed for almost ten minutes – some of the time above the camera (you can hear him tapping with his beak). He gave the box a really good going over before finally leaving.

I’m hoping that such a long check means he likes the place.


jennychemI’ve mentioned JennyChem many times before. I use their Traffic Film Remover when I clean my car and in my homemade screen wash, I periodically sanitise the inside of my car using their fogging machine, and I also buy my hand sanitising gel from them – along with various shampoos and valeting products.

Right now, you can get a 5% discount using the following code at checkout.


I can personally vouch for their products. They’re all excellent quality and they do precisely what they say they do.

To get you started, here are some links to products I use as supplied by JennyChem:

Traffic Film Remover Ultra Special

Snowstorm TFR Maxi Mousse

Cherry Bomb Shampoo

Tar & Glue Remover

Tyre Shine

Fogging/Sanitising Machine

Ceramic Beading Topper

They also supply antifreeze, microfibre cloths, and a vast range of other chemicals and tools.


I had a very eventful weekend.

On Friday, the fuel panic-buying started. I’d noticed queues throughout the day, and I knew it wasn’t going to just blow over anytime soon. My main concern was having fuel for Monday, when I have a pupil on test. I’d already started thinking of cancelling weekend lessons if need be to make sure I could do it. By the end of Friday, I had over half a tank, but I knew it wouldn’t last the weekend and cover Monday’s test.

I get my fuel from Asda, but on arriving well after 9pm Friday evening, and after joining the small queue to the 24 hour pumps, it became clear that they were all locked up because Asda was out of fuel. So I nipped to the nearby Esso garage which had also had queues all day, and it was also closed early because it was out of fuel. I then took a long shot and nipped to a local village outside of the city and managed to fill up there (though they appeared to be short of diesel, and people were queuing).

I was still concerned about the Monday test, though. A tank of petrol would not last much beyond Saturday and Sunday with all the lessons I had scheduled. But on my way to my first lesson on Saturday, events took over. I got two texts in quick succession from pupils cancelling because they had something else on (translation: the Detonate festival was on yesterday, and they were going to that), one from someone’s mother informing me they were waiting for the results of a PCR test, and one from another who had a lesson Sunday and thought that Saturday was Sunday, then realised, and didn’t cancel after all. No problem, that would save me some fuel. Then I got stuck in stationary traffic half way along Wilford Lane, which meant there was no way I was going to get to my pupil on time, and which would then impact the second. I called him and explained, and we decided to stick with the one he had booked Sunday (he normally does both days). I turned around, and then immediately got stuck in stationary traffic going the other way, because there had been a crash on Clifton Bridge yet again in the roadworks. Once I got home, I loaded up Google Maps and watched the traffic movement – it was effectively stationary within 2 miles of the bridge, and remained so until the point where I would not be able to get to my next pupil, either. I contacted her and explained, and we decided to stick with Sunday this week (she also does two lessons week). All in all, Saturday went from four lessons to a day off. But at least I knew I’d have fuel for Monday’s test now.

Sunday dawned. My first pupil lives near the city centre, and I checked Google as I usually do before setting off, and noticed that 90% of the city/ring road side was closed – because of the damned marathon. So I went the long way round to his house and came in from the non-marathon side, which took 50 minutes instead of the usual 20. We drove off from his house, with a destination in mind for the lesson, and immediately encountered a police roadblock due to an accident. We turned around with another route now in mind, and as soon as we got to Mapperley we were met with almost stationary traffic.

The marathon causes this problem every year at the best of times, since people have to find alternate routes to wherever they want to be, which increases the traffic volume everywhere else. But this time it was made much, much worse by dozens of twats queuing for fuel at the Co-op garage on Woodborough Road. The video is a time-lapse, and covers about 15 minutes of real time.

You can’t see it in the video, but a bus was bouncing up and down as it had to go over a bollard kerb to get past. The twats who had filled up then decided that instead of leaving the garage by the rear exit, and having to wait for 30 seconds at the traffic lights on Woodthorpe Drive, they would leave by the Woodborough Road exit and turn right across the gridlocked traffic approaching on both sides, thus creating even worse hold ups. That was why the ‘lane’ we were in was stationary for so long when it ought to have been free moving.

Once we got by, the lesson continued to be eventful. We had to stop for an otter in Stoke Bardolph and then, as we waited to turn left on to Nottingham Road in Burton Joyce, we watched a woman on horseback with two children (one on a pony, and one leading a pony) nearly get killed because the horse was bucking and she nearly fell off.

The last leg of the journey was marked only by people driving straight into then out of the garage on the Gedling end of Carlton Hill (because it had no fuel), and to squeeze through the orange cones on the entrance to the one just after Porchester Road to see if the obvious unavailability of any fuel was true and actually applied to them, too. Oh, and my pupil nearly colliding with his mother as she drove away from their house rather too quickly on a blind bend with parked cars on both sides.


Well, here’s something you don’t see everyday in Nottingham. In fact, it’s the first time I have ever seen one in the flesh (or fur) anywhere in my life.

I was on a lesson and we were driving through Stoke Bardolph. We’d just gone past the pub when I noticed what I first thought was someone’s coat at the edge of the road. But as we got closer I realised it was an animal. The words ‘stoat’ and then ‘dog’ (when I realised how big it was) passed through my mind.

But absolutely the last word I expected to end up with was ‘otter’.

I’m not an expert on otters, but what little knowledge I have from nature documentaries is that they are quite fast. This one did seem to be limping – maybe. And it was much bigger than I thought they were. It stopped on the grass at the side at the river and alertly watched us go by. It’s times like these when I wish I carried my proper camera everywhere with me.


I had my first non-insectoid and non-arachnoid visitor to my birdbox today. What appears to have been a Great Tit popped in and cased the joint.

He (or she) inspected every corner, and even checked the walls for integrity.

Apparently, this time of year they’re looking for places to roost, so I hope he comes back and then sticks around with a mate next Spring.


We’re now officially into autumn, and I’m getting a lot of hits right now. If your Birch is just starting to show a few yellow leaves, it’s not unusual. The Elms are already turning, because it’s what they do around autumn. My Birch is still fully green, and the feeding and heavy watering has had a lot to do with that. If you haven’t been watering, remember that it’s been a dry summer, so yours may turn earlier. Just prepare for next year and start feeding and watering from March.

Our Silver Birch in June 2017Back in 2014, when I originally wrote this, our Birch tree suddenly began to produce a lot of yellow leaves in mid-June. After a lot of research I managed to figure out the possible causes and the remedies. That was the purpose of the original article.

However, 2018 threw up a new issue. It turned out to be the hottest year on record, but even before we found that out people will remember how hot it was, and for how long it stayed like that. My tree once again began to show a few sprays of yellow fairly early in the season.

The article becomes popular each year, firstly in late Spring and early Summer, then again later in the season closer to Autumn.

In 2014, I identified the following as likely causes of premature yellowing:

  • nutrient deficiency
  • iron deficiency
  • manganese deficiency

After the 2018 heatwave, I further identified lack of water as a major factor. With hindsight, it may have also been a factor in that 2014 season, but nothing compared with 2018 for prolonged heat and lack of rain.

When I first experienced yellowing back in 2014, I initially thought my tree was dying. Googling for an answer was pretty much useless, because most of the technical advice is American and focuses on the Bronze Birch Borer (a beetle that feeds on white birches), which isn’t known outside of  North America. But somewhere in among the advice, I came across a simple comment – and I don’t recall where I saw it now – that made a lot more sense.

In a nutshell, premature yellowing/leaf drop can be caused by nutrient and iron deficiencies in the soil. This comes about over a period of time as fallen leaves are swept up each year and sent to the tip, so none of the nutrients are returned to the soil. Consequently, the soil becomes depleted of them.

Birches are ericaceous – lime-hating – plants, and prefer a slightly acidic soil. As such, you need to feed them using ericaceous fertiliser. I first used Miracle-Gro solid fertiliser, intended for Azaleas and Rhododendrons (also lime-hating), but a couple of years later switched to Doff liquid feed so I could use it in my Access Irrigation Static Dilutor. I also got hold of some Maxicrop Seaweed Extract, which is also liquid, and watered that in at the same time.

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My original problem showed itself as canary-yellow leaves, either in sprays, or randomly dotted throughout the canopy. On closer inspection, some of the leaves looked like those in the photograph here.Leaves suffering from chlorosis

This is known as chlorosis. Leaves are usually green because they contain chlorophyll – and chlorophyll is green. Chlorophyll is what allows plants to convert light energy into sugars that they can use as food through the process called photosynthesis. Plants use iron to produce chlorophyll, so if there isn’t enough iron in the soil the tree can’t make enough chlorophyll, and you get yellowed leaves. The tree compensates for being hungry (if it hasn’t got chlorophyll it can’t make food for energy) by going into shutdown and shedding those leaves. And you may also find that new leaves are small and misshapen when chlorosis is the issue.

You can easily treat chlorosis using sequestered iron (or seaweed extract). Being ‘sequestered’, the tree can suck the iron up and use it right away. A longer term solution is to use iron sulphate lawn feed, which also slightly acidifies the soil over time.Close-up of leaves suffering from chlorosis

I also bought some manganese to water in the first time, but I am not sure how relevant that was. I used it for a couple of seasons, but stopped. Each year, I simply feed the tree once or twice a month between March and September using fertiliser and seaweed extract.

Note that none of these problems are confined to Silver Birches. All trees and plants can be affected by nutrient deficiencies, and you simply have to deal with the problem using the appropriate, easily purchased treatments.Close-up of our tree's leaves in June 2017

In that first season, a single application of fertiliser stopped the leaf drop almost immediately. Once the already-yellow leaves had fallen, the tree remained green until Autumn, and even threw out some large new leaves and fat catkins. It obviously liked what I had done to it, and I continued doing it from June until September every few weeks.

Everything was fine until the hot summer of 2018. You might recall that the prolonged heatwave began quite early, and by the end of June I was again noticing a few sprays of yellow. I wasn’t a nutrient issue this time – I was feeding the tree regularly – but I’d already guessed the hot weather might have something to do with it, and a bit more research showed that heat stress in trees is a real issue, and Birches are highly susceptible to it.

It turns out that lack of moisture in the ground combined with prolonged high air temperatures causes trees – and especially Birches – to become stressed, which again triggers them to go into emergency shutdown by shedding leaves.

My research provided two options for getting water down to the roots (which fortunately, in the case of Birches, is quite shallow). One involved hammering at least half a dozen hollow spikes into the ground around the tree and dripping water directly down to them. I decided against that on the basis that a) the ground was already as hard as iron plate, b) anything which sounds so simple (i.e. hammering a hollow plastic spike into the soil) was going to turn into a nightmare of split plastic, only being able to get part way down, and discovering chunks of bedrock I didn’t know were there, and c) having these things poking out of the lawn would look bloody awful even if I got them in (and even worse if they only went in part-way). The easier option was to commence heavy-watering immediately – basically, to run the sprinklers for hours at a time every  night.

That method fixed the problem in less than a week.

With hindsight, it is quite possible that lack of moisture was a contributing factor back in 2014, and my feeding routine would have dealt with that automatically (though I did have chlorosis). But in 2018, it was definitely just the result of too little moisture around the roots.

So, to summarise. If you experience premature leave-yellowing, the very first thing you should do is water like crazy. Don’t worry about over-watering too much – Birches like wet soil, which is why they grow near streams. Just don’t turn your garden into a swamp. While you’re doing that, buy some ericaceous feed and seaweed extract, and get that into your soil as soon as possible (how much depends on how big your tree is).

Can you rescue leaves which have turned yellow?

No, probably not. I suppose that chlorosis could be reversed if you caught it early enough, but if the leaf is dead and the tree has triggered its shedding mechanism, you’re going to lose them.

The important thing is that by feeding and watering the tree you can stop any further yellowing – and believe me, the first time you do it the effects will be quite noticeable within a short time.

Do you have to keep treating the trees?

Yes. If you don’t, the problem just comes back once the tree has used up what you’ve fed it, especially if you bin the leaves again the following autumn. Huge trees will suck up all the nutrients and water, and if you’re raking up and binning the leaves each year (or if the soil is dry and there are no prolonged periods of rain) nothing gets returned to the soil.

How often should you feed?

Treat them once or twice a month from March until September. And water regularly.

Can heat and drought cause them to lose leaves?

Yes. If they are stressed you may get them dropping leaves. In extreme cases the leaves can go brown and the tree can even die. It’s a good idea to water them deeply during hot, dry periods. Once or twice a week should be enough, though more frequently won’t hurt if the dry period is prolonged.

Remember that after a period of drought (or prolonged dry weather) it needs an extended period of rain to wet the soil again, especially deep down. A few heavy downpours won’t do it, and you will still need to help things along.

Will a Birch recover from drought?

It depends on whether the drought killed it or not. A reader wrote to me in 2018, mentioning that his tree had lost its leaves, and I advised that the only thing he could do right then was to feed and water – and hope for the best. He wrote to me in 2019 to tell me the tree had started to rock in the wind, and that a tree surgeon had subsequently declared it dead, and had had to remove it. Apparently, the roots were rotten.

There’s no way of knowing if it was just the drought that did the damage. The tree may have been weakened by not feeding and watering over previous years, and the drought was just the final nail in the coffin. But the 2018 heatwave certainly caused problems.

Is there any other way to deal with the problem?

You have to get nutrients and iron back into the soil. And you need water in order for the roots to be able to access those nutrients. Yes, you could use your own mulch or bought compost, but obviously this is not so attractive in a normal garden (removing it is what got you here in the first place). It would also take longer to have an effect. But it would still work, given time.

When do Birch trees normally start to shed their leaves?

In the Autumn! In the UK this is from around September-October, and the onset varies up and down the country. It often seems triggered by a noticeable drop in night time temperatures. The leaves will begin to fall from that point – very lightly at first, then increasing as the yellowing spreads.

Why do birch trees drop leaves so early?

They don’t. They drop them in Autumn, like all other trees which shed their leaves each year. If yours is turning early, you may have a problem.

How do you apply these treatments?

You make up the required solution as directed on the pack, then water it into the area specified. I use a combined watering/fertilising system, which I have written about separately. However, you can use a watering can and hosepipe/sprinkler as necessary. Note that if the ground is dry, a watering can won’t get the nutrients down to the roots, so a heavy watering is essential.

Why are fallen leaves sticky?

You’ve probably got greenfly! Specifically, the birch aphid, Euceraphis betulae. They feed on the European Birch, Betula pendula, and they increase in number during warm and dry weather. Aphids secrete honeydew as they feed, and that’s the sticky stuff you’re seeing. Apparently, you can get different species of greenfly that feed on specific trees.

You can kill them with a soap/water mixture, though no one has ever been able to tell me precisely how you apply that to a 20 metre high tree. And the same goes for any chemical method relying on direct contact. An alternative solution is to introduce predatory insects – something that eats aphids. The best one is the Ladybird larva, and you can buy them online. There are other predatory insects you can buy, too.

My tree is losing branches and twigs

If the tree is weak then it is understandable that twigs and small branches might fall off. Once they’re stronger this will stop. In any case, if it is windy, a few dead twigs are bound to fall off. It’s just nature – and birches also have a fungus which can cause small twigs to die and fall.

In the Spring, Crows can also be a problem if they’re nesting nearby. They are very, very selective in their choice of twigs for the purpose, and they will tear off dozens until they get the right one. It’s nature, so we don’t worry when they’re using ours for their twigs.

When do birches start to show leaves?

In Spring, obviously, but the precise date varies depending on both the tree and the weather. In 2019, they were about a month earlier than 2018 in the UK. Mine is usually showing leaves sometime during April each year.

I’ve got catkins but no leaves

Someone found the site in April 2018 with that query. You’ll probably find that in a couple of weeks you’ll have lots of leaves. As I have said in this article, I start feeding mine from March onwards. Leaves start sprouting a week or two earlier than my neighbours’ trees, and the foliage on mine is usually much denser. The catkins often come before the leaves.

Are the leaves changing early this year?

This was a generic search term used to find the blog in mid-July 2017. The short answer is no, they are not – not in July in the UK, anyway. They change towards the end of September in the UK.

Do Weeping Silver Birches lose their leaves in Autumn?


When do Silver Birch leaves go all brown?

They don’t. The leaves should go yellow and fall off in the autumn.

I had quite a few visitors from this search term in 2018, and when I looked it up it seems that extreme cases of chlorosis and heat stress can result in leaves turning brown (see this supplementary article). It could also be a disease or infestation which you could treat, but the tree itself might also be dead – especially if it has been having any of the problems I mentioned above over previous years. Best to call in the experts.

Does this advice only apply to Silver Birch trees?

No. Chlorosis can affect many plants, and lack of nutrients is a universal issue. You might need a different fertiliser to address any nutrient problem, but iron will likely fix chlorosis. Lack of water can kill virtually any plant.


The Chillmax AirAlso applies to InstaChill, Chill Tower, etc. I wrote this in the very hot summer of 2019. I get a huge spike in traffic several times each year whenever it gets hot.

Note that tonight I saw a new JML advert for the InstaChill. It is a larger version of the ChillMax, and it costs a lot more, too. But it works in exactly the same way. However, there is no way I am going to test one of those.

Be aware that these devices do not work to anything like the levels claimed. The original article follows.

Early in July 2019, I saw the Chillmax Air advertised on TV in one of those shouty ads. Then, the same evening, I was shopping in Asda and saw it on display. I am an idiot for things like this, and bought it on impulse so I could test whether it worked or not.

As a chemist, I know that in order to cool a large space effectively you’re going to need something with a big fan and a special refrigerant. In practical terms, that means a fairly bulky device with a motor-driven compressor, a closed radiator for the refrigerant to pass through, a fan to suck air in and blow it across the radiator, and a wide exhaust pipe through the wall or window to get rid of the ‘removed heat’. In some cases, you also need to collect or drain the condensed water that comes out of the air as it cools. A typical proper air conditioner for a small or medium-sized room will be about the size of bedside cabinet. The Chillmax Air is not much bigger than six CD cases glued into a cube.

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If you’ve used a normal desk fan you will know that you only feel cooler if you’re sweating a bit. That’s because the fan evaporates your sweat as it pushes air over it, and that evaporation is accompanied by a small cooling effect – it’s called ‘evaporative cooling’. If you’re not sweating, you don’t feel the effect. Conversely, if the surrounding air is very humid, then no matter how powerful your fan is, you will feel little or no cooling because sweat can only evaporate if the air has capacity to hold additional moisture (I’ll explain that a bit more later, because it’s what determines whether the Chillmax is any good).

As an aside, many liquids exhibit the evaporative cooling effect. In the case of diethyl ether (the stuff they used to use as an anaesthetic), if you force it to evaporate very quickly you can even freeze water (if you do it properly). However, ether is both highly flammable and toxic, so apart from demonstrating it in the school lab (where I remember it from, partly due to the massive headache the fumes gave me), it doesn’t have much practical application these days. Early refrigerators used it, which was spectacularly dangerous.

The Chillmax Air uses the evaporative cooling effect of water, and this is much less than with ether – similar to sweat, in fact. The unit consists of a reservoir at the top, which you fill with normal tap water, and this drips down on to a radiator unit which has ten sideways-stacked fibre panels in it through which a fan blows air. The water evaporates from the fibre panels, and the evaporatively cooled air comes out through the front grille. According to the marketing spiel on the TV ads, you’d be forgiven for thinking you’re going to get frostbite if you sit too close. I knew this wasn’t going to happen, but I wanted to know just how effective the Chillmax was.

When I first set it up and turned it on, the first thing I noticed was that the fan is quite powerful, so you get a good flow of air directed at you – but note that that it’s only a 5″ computer fan, so it can’t beat a proper desk fan for air flow. The air did seem a little cooler compared with what my desk fan was blowing at me, but it also felt ‘softer’ – that’s very important, and I’ll explain later. But the big question was how much cooler was the exhaust air?

I fired up my trusty data logger and left it in front of my desk fan for 30 minutes for the control data. Then I moved it and suspended it in front of the Chillmax for the same period of time. This is what it recorded (the red line is where I moved it).

Chillmax - temperature log in hot and sticky conditionsThe ambient temperature where I ran the test was about 29ºC. The Chillmax brought this down by about 4ºC.

So, the Chillmax definitely cools the air that passes through it. Let’s work on the assumption that it would be able to get the same 4ºC drop no matter what the ambient temperature was. If your room is 38ºC, pulling it down to 34ºC still means it’s bloody hot. And also note that since the Chillmax is physically so small, the cooling is very localised – it won’t cool a room down, and you have to have it less than a metre from your face to feel anything.

Now, some people might be thinking that a 4ºC is better than nothing at all. And they’d be right if it was just a matter of temperature. But there’s more to it than that. I mentioned that the exhaust from the Chillmax felt ‘softer’. I knew what it was, but my data logger shows it in numbers.

These are is the data for relative humidity recorded at the same time as the temperature measurement, above (the red line is where I moved the logger). The humidity went up dramatically – a jump of about 30%RH.

Chillmax - RH log in hot and sticky conditionsAs I’ve already explained, the Chillmax works by evaporating water on fibrous panels by forcing air across them. That water has got to go somewhere, and in this case it comes out as vapour in the cooled air. In the right light, you can actually see it – it’s essentially fog. And just like when it’s foggy outside, and everywhere gets damp, this vapour can condense on surfaces. My data logger collected some and began to drip during the test, and I have since discovered that it also condenses on the front grille and can drip periodically, so you’d need to be careful what you had underneath it if you placed it on a shelf. The fan is quite powerful enough to project the drips forward slightly when they drop.

The ambient humidity in the room where I did the test was about 44%RH. The Chillmax sent that up to over 70%RH.

It’s this elevation of the humidity of the cooled air which really brings into question whether the Chillmax is worth the investment. You’re probably aware that you can have a hot summer day in the high 20s where it is pleasant and comfortable, but a cooler and overcast day might be horribly sticky – or muggy. That’s because of the humidity, or water vapour in the air.

The amount of water vapour that air can hold varies with the temperature. Once you reach the maximum, any extra vapour condenses out as a liquid – misted up windows, dampness, even drips and pools of moisture on window sills or under lamp posts. Cold air can only hold a small amount of moisture before condensation occurs, but hot air can carry much more (think ‘sauna’). Although ‘humidity’ technically refers to the amount of water in the air, the figure most people are referring to when they say it is relative humidity. This is the amount of moisture in the air expressed as a percentage of the maximum amount it could hold at that temperature, hence the units %RH. It’s a very complicated subject, but the important factor for us here is that when it is warm or hot, higher relative humidity is uncomfortable. Indeed, you may have seen weather forecasts where they give the actual temperature and the ‘feels like’ equivalent – that’s a reference to the ‘Heat Index’, which takes into account the effect of the %RH. Here’s a graphical chart for that.

Heat Index - graphical representationAs an example, if the air temperature is 30ºC and 50%RH, it will feel like 31ºC, but if the humidity goes up to 80%RH, then it will feel like 38ºC – even though the thermometer still tells you it’s 30ºC.

Another example. If the air temperature is 35ºC, at 50%RH it will feel like 41ºC, but send the humidity up to 80%RH and it’ll feel like 57ºC – even though the thermometer still reads 35ºC.

The calculation for this is complex (you should see how long my Excel formula for it is). It is non-linear, and the increase in ‘feels like’ is greater at higher temperatures. It also contains an element of opinion/perception, which is why there’s no point using numbers above about 60ºC. But the ‘Heat Index’ is what forecasters use. Incidentally, the official health designations for the colours are: yellow – caution; amber – extreme caution; orange – danger; and red – extreme danger. Vulnerable people need to take these into consideration before going out in hot weather.

However, this is where the problems come in for the Chillmax and similar devices. If it’s 35ºC and 40%RH, it’ll feel like 37ºC. Cool the air to 31ºC but send the humidity up to 80%RH, and it’ll feel like 41ºC. So it’s actually hotter in terms of comfort. Do the same comparison when the surrounding temperature is 38ºC, and the ‘feels like’ goes from 43ºC to over 50ºC!

At lower temperatures the Chillmax will produce a slight net cooling effect. But if the air temperature is above about 30ºC (and 50%RH) – which isn’t excessively hot or humid to start with – it’ll actually make you feel warmer. And if it is already humid outside, you’ll feel hotter still.

Proper air conditioners remove water from the air they cool. This removal of moisture is why the air from proper air conditioners feels crisp, as opposed to the ‘softness’ of moist air. The Chillmax does the opposite of normal A/Cs, and adds moisture.

Aesthetically speaking, the Chillmax is a cube – more or less – about 15cm along each side. There are two buttons on the top rear, one which changes the fan speed to one of three settings (or off), with a blue LED for each, and another button that turns the night light on or off. There’s a flap on the top front through which you add the water. The radiator system is a plastic-framed insert which you access by pulling the front grille out. It slots in and out easily. You can’t officially replace the fibre inserts in the radiator, but you can buy the whole radiator assembly from JML for £15. My only major gripe is the power cable. The jack plug that goes into the Chillmax is quite stubby and doesn’t go into the socket very far, so it is easy to dislodge it. However, the cable itself is quite long, and the  mains plug is a moulded UK type.

JML claims the Chillmax can run for up to 10 hours per fill, but this is likely on the lowest of the three fan speeds, since on top speed it runs out in less than three hours.  JML sells the humidification as a positive without relating it to the comfort relationship between temperature and %RH, but note what I said above. If you want to cool down in humid weather, it isn’t just the temperature that needs to come down.

Does it really work?

It does cool the air by a few degrees, so in that sense it works. However, it also sends the humidity up, and in most cases that actually makes you feel hotter and more uncomfortable. In that sense, it doesn’t work.

Will it cool more if I use ice water?

No. Evaporative coolers are not influenced significantly by the temperature of the water used in them. The temperature of the air that comes out depends on the temperature (and humidity) of the air going in, and the science of evaporation. Only this evaporation results in the cooling effect observed.

Will it cool more if I put the filter in the freezer?

It might – while you’re blowing air over ice. But once they defrost, which will happen in a few minutes in the temperatures you’ll likely be experiencing, then no. You’ll also have more condensate to deal with from the melted ice pouring out of the front grille.

You may see reviews on Amazon claiming that freezing the filters (or using ice cubes in the water tank) does give cooler air. Trust me – apart from what I just said about blowing air over ice, it doesn’t. Science is involved, and evaporative cooling doesn’t work like that.

Can I use it to cool my PC?

Someone found this article on the search term “jml chillmax air for pc cooling”. No. Blowing damp air into your PC would be dangerous, potentially expensive, and would only gain you 4ºC at best.

Can you get larger versions?

Until August 2021, the answer in relation to the ChillMax was no. However, I saw an advert (as shouty as usual) for the InstaChill tonight. Unlike the ChillMax, which is the size of a small table top radio, the InstaChill is the size of a bedside cabinet. And you can certainly get larger evaporative coolers from other manufacturers. The working principle is identical, except that the larger the surface area of water, and the greater the airflow over that water, then the greater will be the possible drop in temperature at the front end (and the more moisture being pumped out to increase the humidity). However, cooling effectiveness is influenced greatly by the RH of the air going in.

If the air is very dry, then a large evaporative cooler might be able to drop inlet air at 30ºC down by as much as 10ºC. However, if the inlet air is very humid, the temperature drop could be as little as 1ºC. In the UK, the realistic temperature drop you could expect on a non-humid day for a large cooler would be around 5-6ºC, but on a sticky day you’d only get about a 3ºC drop.

Suppliers of these devices say that they need good ventilation or extraction, and I would imagine that’s so the humid air can escape. If you’re evaporating more water to get better cooling on larger devices, you’re also producing a lot more water vapour, so the cooling effectiveness will decrease as the humidity rises unless you vent it somehow. Be careful if you read any of the reviews on these things – people may have noticed cooling in already cooler conditions, but trust me – if it’s very warm and humid, you will not notice any effect.

People say it works

Be careful when you read those one-line reviews. If you test it when it’s only 20ºC outside – as many of these people have – then yes, it blows noticeably cooler air at you. But science is involved, and at temperatures above about 28-30ºC you’ll actually feel hotter. The fact that it increases humidity is the key factor. Remember that the reason you even found this article was probably because it’s over 30ºC outside – the more above that it is, then the more hits I get.

So, does the Chillmax/InstaChill work?

They cool the inlet air by several degrees. But they send the humidity of that air up considerably, and this cancels out the benefits of the cooling effect when it is very hot. The ‘Heat Index’ is the key detail, as explained above. In the case of the InstaChill, it will add a lot more humidity than the ChillMax, and as I have explained and demonstrated, the ChillMax is bad enough when it comes to increasing the ‘feels like’ temperature.

Only the air being directed at you is cooler. Once that slightly cooler air has passed through warmer air, it’ll be close to ambient again. The device cannot cool down a room. It’s far too small for that.

Humidity can carry much further, though. So in a small room, you could easily increase the ‘ambient’ RH without any cooling at all, and that will make it feel even hotter. If it is already hot, the amount of water vapour the air can hold before reaching 100% RH will be substantial. The increased humidity of the outlet air does produce localised condensation, so you have to be careful to keep these devices away from electrical sockets where they might drip on them. They also contain a significant volume of water when full, so you don’t want to knock them over.

Should I buy one?

My advice is to buy a proper air conditioner (A/C). If anything costs under £200 it is not a proper A/C. However, it is possible some people might find the minor cooling effect and increased humidity of the Chillmax/InstaChill (and similar devices) beneficial, so the choice is yours. But for real cooling and dehumidification when it is hot, it has to be a proper A/C.


The empty bird box at nightI have a new toy. A birdbox with a camera fitted into it. I will be installing it outside over the next few weeks, and maybe I’ll get some roosting birds in the autumn and winter, but I’m hoping to get them nesting next year.

The plan is to get Blue Tits nesting in my box. If that works, I intend to get another box and entice our Robin, who is tame enough to fly against you if you’re out gardening to let you know he or she is there so you can feed him/her mealworms (he won’t take them from your hand just yet, but he’s getting close on that).

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The birdbox I bought is from Green Feathers. They also supply their kits through Amazon. I chose the deluxe kit, which includes the birdbox, Wi-Fi HD camera, and all the necessary accessories. I also bought the daylight LED lamp to illuminate the inside of the box.

It comes with excellent instructions, and is easy to assemble as long as you can use a screwdriver (and perhaps an awl or small drill), and it connects to the Green Feathers app equally easily. I had it running with a live feed to the app within a few  minutes. For most people, that’s really all they need. The app tells you when any birds visit (motion detection). The camera also has a microphone, so you’ll be able to hear any sounds the birds make. The LED lamp (optional extra) uses a sensor to detect daylight, and turns on during the day to give a true colour feed. At night, the LEDs turn off automatically, and the camera records in infrared (black and white). You can record the video stream and save it through the app, and you can also take snapshots. For most people, the birdbox and app are all that is required. But me being me, that wasn’t enough.

I am not a ‘millennial’, but I am computer literate (I have been building and repairing them for over 20 years). I cannot see the attraction of doing everything on your smartphone when you have a PC in front of you. Fine, getting a live feed of the birdbox to your phone is pretty cool, but this is a HD camera we’re talking about, and there is no way on God’s green earth that you can get a decent HD image on a smartphone. They’re just too damned small – especially iPhones, which most millennials seem to want to own at all costs.

So, once the system was running on the app, the next thing I did was download ONVIF Device Manager (Green Feathers cameras are ONVIF devices). It is a network video client, which means it can access and manage as many ONVIF devices you like. On running it for the first time, it immediately saw my BirdCam, and I was able to view the video live feed on my PC.

Then, I turned to my Synology NAS, and set up Surveillance Station. Now I know most people won’t have a NAS, but I do. Surveillance Station is software on the Synology NAS which monitors multiple video feeds, and allows recording and playback. It is mainly intended for security cameras, but it will work with any IP Camera (which Green Feathers cameras are). It, too, picked up my BirdCam immediately.

Note that ONVIF Device Manager and Surveillance Station are completely independent of each other, and have little if anything to do with what I wanted to do next (ONVIF did help me identify my video feed address). ONVIF Device Manager was simply playing around (and understanding what was happening), and Surveillance Station would provide an alternative if what I did want to do next turned out to be difficult or prohibitively expensive.

My main aim was to be able to put a live feed of my BirdCam on the blog.

I’ve not done anything like this before, though I knew it was possible. But how? My first thought was that I could provide the feed directly from my computer, but my internet provider might not be happy (or capable of it) if I tried to do it through my router, and my router might not be happy if more than a couple of people tried to view the feed at the same time. It was clear that I needed a media server service, where I provided a single feed, and the server managed the necessary bandwidth and distributed it to others.

To that end, after some searching – and being put off by silly prices – I came across ipcamlive, who do just what I wanted. I’d got this far on my own, but I have to admit I needed to contact their technical support a couple of times to get it working. However, thanks to them, I can now be certain that I can do a blog page with a live BirdCam feed on it.

Right now, all I have to do is bolt the bird box to the shed and I’m set to go. And hope that some Blue Tits like the location enough to set up home next spring.

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