Raspberry Pi as a Naturewatching Camera

Those of you who watch Springwatch on the BBC are probably already ahead of me. I was interested to see that there was a short article in one of the programs on a “£25 Nature Watching Camera” from MyNaturewatch. It turns out that this is an (almost) perfect application for the Raspberry Pi so I decided I would give it a go using one of my idle Raspberry Pi Zero W and a camera I bought when I bought my first Raspberry Pi.

It was simple to do, just by following the instructions on their website I built the camera in a couple of hours. Then I hit a couple of snags. The first was because I didn’t follow their instructions and the second because (I think) the Pi must be running quite fast and (again I think) it overheated and stopped running.

The first problem was that I assumed I would be able to access the operating system with the code they had provided and spent a while trying to access the Pi to connect it to my WiFi network. It turns out that the camera is a server and therefore you have to access it through a client (either a smartphone or PC). (Note to self for future reference – read the instructions fully).

The second is more questionable and I don’t yet know either if it is the problem or if gluing a home-made heatsink to the chip has made any difference.

The User Interface is a bit clunky and its difficult to know if it is running or not. In particular I found connecting it to my smartphone (an iPhone 6s) didn’t always work and so one was left with the question as to whether it was running and just not operating as a server properly or whether it had stopped running. It would be helpful if there was some external indication that it was running (e.g. if the camera LED blinked occasionally). A related problem is that you’re dependent upon the video streamed from the Pi to your smartphone to line up the camera on the target.

Apart from these niggles, it works fine and I’ve ended up with hundreds of photos of the birds on my feeder. a few of which are shown below. As you can see we have a family of Greater Spotted Woodpeckers who visit regularly.

If you like this sort of thing and/or you want to get your kids interested, I would recommend this. If you can find a more stable platform to watch, you won’t end up with as many pictures of a swinging birdfeeder as I have.


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Tomato Halms Gelbe (Hahms Gelbe)

I've called this Halms Gelbe, but there is a good chance it is actually Hahms Gelbe and I've just mis-read the label on the packet (since discarded so I can't check)


One of the new 2018 cultivars and (in May) nothing to report on what the fruit look/taste like. However, the plant is stocky and growing well. Its a mini-dwarf plant (very short) so its being grown on the bench in the polytunnel along with the other Determinate varieties. More pictures will be added as it grows and crops.

Halms Gelbe

Quick Facts

  • Fruit Type: Cherry
  • Fruit Shape: Round
  • Fruit Size: Small
  • Fruit Colour: Yellow
  • Flesh Colour: Yellow
  • Plant Type: Determinate
  • Seed Type: Open Pollinated
  • Leaf Type: Regular
  • Time to Ripe: Early (60+)
  • Taste:
  • Fruit per Truss: N/A
  • Truss Spacing: N/A
  • Alternatives:
  • Our Source: Seed Swap

Buy Your Seeds Here

  • No Source yet identified

Buy Your Plants Here

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Polytunnel Vegetables


Polytunnel May 2018

We’re now into late May so the polytunnel is beginning to get planted up. Up until now, its been providing us with lettuces and swiss chard but the swiss chard is coming to an end so now the summer vegetables get added.

I’ve decided to follow through with similar planting to last year, Dwarf French Beans (of various sorts), Climbing French Beans (ditto), courgettes, cucumber and other things that I’ve yet to decide. Most of the French Beans are from my own saved seeds and this seems to be a successful way of building a large selection of different sorts. My idea is to grow a small number (say five or ten plants) of each of a larger number of varieties. This means that they crop over a longer time and have different colours and shapes without having to buy lots of seeds each year.

The plants on the bench at the far end of the tunnel are my tomatoes which are still waiting to be put into their final pots from where the determinate (bush) varieties will go back onto the bench and the Indeterminate (cordon) varieties will go into the greenhouses.

I’m not growing as many different varieties of tomato this year, partly through laziness and partly because we are reducing the number of freezers that we have so there isn’t as much space for tomatoes to be stored over the winter.  Many of the varieties have come from seed swaps but some are my own seeds saved from previous years.

The cucumbers and courgettes are nearest to the doorway (and so don’t show on the picture at the moment) because the end nearest to the camera is the sunniest part of the polytunnel.

As last year, my plan is to keep a record of the harvest and upload it to MYHarvest. Its interesting that their records for last year show that courgettes were the second most common vegetable to be grown on allotments and back gardens (after potatoes). I suppose it shows how easy they are to grow.

Anyway, off to pick a few strawberries to have with lunch. We won’t get many strawberries this year as we’ve only just established the strawberry bed but, when mixed with strawberries bought from the supermarket, they make a nice burst of additional flavour.

Keep gardening and let us know how you’re doing.

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Bokashi Composting

I stumbled across this the other day. It’s an informative podcast about Bokashi Composting and it reminded me that I need to start my Bokashi up again.

For those (many) of you who haven’t heard of Bokashi Composting, it’s an Asian technique re-introduced in the early 1980s which uses a starter inoculated with microbes to start the composting process of all of the kitchen food waste. By all, I mean exactly that, not only uncooked vegetable peelings but, more usefully, cooked food, meat, fish, etc., etc..

It’s an anaerobic process that, over the period of two weeks or so, turns food waste into something that the soil microbes will break down into useable, highly fertile, compost. It doesn’t create the brown, crumbly compost that you can scatter all over your garden, rather it prepares kitchen waste that would otherwise go to landfill into something that you can bury in your existing compost heap or straight into the ground if you prefer.

Why do that (I hear you ask). Well, we bokashi to increase the fertility of the soil, reduce the amount we send to landfill and to reduce the smell of the landfill bin by not putting any food waste into it. When we are running the bokashi bin (we run it is spring, summer and autumn but not over the winter) we know that we have less waste, the kitchen bin doesn’t smell and when we look at the compost, its full if worms and breaks down more quickly than it would without the bokashi.

What is Bokashi & how does it work?

Bokashi is an anaerobic process that “pickles” the waste. Unlike traditional composting, at the end of the process, all of the items of waste are sill identifiable, covered in a white mould and ready for the microbes in the soil to break them down and return their nutrients to the soil. It relies upon mixing your waste with bran inoculated with the micro organisms so that the micro organisms can mix with the waste and prepare it for use. To be honest, the science is beyond me but it seems that the micro organisms create lactic acid which prevents rotting but at the same time breaks down the structure of the waste making it ready to be composted.

When running the system, we use two bins, one bin being filled and the other sitting “maturing” for the two weeks it needs to work. We use it alongside a separate system for vegetable waste that we compost directly (vegetable peelings, etc.), but we sometimes top it up with compostable vegetable waste if its taking too long to fill the bin. Filling the bin involves alternating a couple of inches of waste with a generous couple of tablespoons of bran (one of the possible problems is being mean with the bran in which case the waste can start to rot – you’ll have to find your own balance) and pressing it all down firmly to exclude the air.

Whilst filling and maturing, the bin will generate “bokashi tea”, a brown liquid which contains the microbes and other wonderful stuff. Water it down to use it as a fertiliser or pour it onto the compost heap to help composting.

After maturing for two weeks, we usually bury the bokashi mix into the compost heap where it breaks down and adds to the standard compost but you can bury it directly into the soil and (usually) animals leave it alone (we’ve had one occasion where a fox dug its way in to the bokashi).

Why not run it all year?

We keep our bokashi bin outside the back door. This makes it simple to drain off the liquid and is easily accessible. People say that the process is odourless, but our view is that it has a mild smell, similar to brewing. As we don’t brew in our kitchen, we find that the smell is noticeable but not unpleasant. So we place our bin outside. We tried it over winter the first year but felt that the system didn’t work very well in the colder months so we don’t use it in the three months of winter. However, we know people who do run a bokashi system all year with the bins in their kitchen so perhaps we’re just over sensitive.


Bokashi is good for the environment, improves soil fertility, gets rid of waste that would otherwise got to landfill and overall is a good thing. Why not give it a try?

You can buy a starter kit and bran from Evengreener if you’re in the UK or (if your in the US or Canada) try Bokashi Living either way, you’d be doing your bit to make the world a better place.

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The Weather is improving

The weather gods must have been listening when I last posted, the weather has improved (somewhat) and we’re now back to what I would expect to be getting in April (showers and sunshine). So spring has come with a rush and we’ve got peculiar combinations of plants in flower in the garden at the same time.

We had Blue Tits in one of the birdboxes for a few days but they seem to have gone away. My thought was with the oak being late into leaf, the caterpillars were also late and so the birds were unable to get enough food for their young (either that or the adults were had by the sparrowhawk which frequents our garden.

The frogspawn has hatched and we seem to have a reasonable supply of tadpoles (assuming the ducks don’t eat them) but we haven’t seen any live frogs in the pond. I say live because the crows seem to have managed to find them and we’ve had a couple of dismembered frogs by the pond.

The tomatoes are still struggling to burst into life (actually looking back over photographs I’ve taken in previous years, they look much the same) despite having a few days of record breaking temperatures. What is different this year is that there’s more light in the polytunnel and greenhouses because the trees are later into leaf. Despite it not being ideal, the only place that I was able to put up the polytunnel and greenhouses is shaded by an oak tree throughout most of the morning. However, this year, because the oak is a fortnight later coming into leaf, the sun is shining brightly on them, raising the temperature quickly in the morning. The bad thing, as a result of this, is that the temperature in the polytunnel is going up and down a bit more than I would normally expect.

I planted the raspberry canes from the allotment and the first of the dwarf french beans in the polytunnel earlier in the week. The Strawberry plants are growing well and, hopefully, we will start to see some fruit in the next few weeks.

My raised bed is due for delivery today. The ground isn’t ready for it but I wasn’t expecting the delivery to be so quick. My plan (subject to modification) is to lay one raised bed this year, see how it goes and then to lay another later in the year. I had a look around at various places for raised beds, thought about using sleepers and other forms but ended up with WoodBlocX. They’re not cheap but, unlike many other places I looked at on the web, they look substantial enough to last many years whilst not being so thick as to take up a lot of space just for the surround. We shall see. Anyway, when its in, it’ll provide somewhere to put all the leaf-mould and compost we seem to have collected over the past couple of years.

So, all in all, spring is definitely on the way.

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When is it going to get warm?

I spent most of this morning transplanting my tomatoes from their seed pots up into individual pots. They need it to allow them to grow on faster but, I wondered when it was going to get warm.

Those of you who have looked at the Raspberry Pi part of this site will know that I’ve been measuring and recording various temperatures (outside, in the polytunnel and in a barrel of water in the polytunnel) to see whether a barrel of water in the tunnel can improve (i.e. raise) the temperature in there.

However, what it shows is that, even in the warmth of the polytunnel, temperatures are really struggling this year. Not only did we have various “Beasts from the East” during March, but the weather in April has been damp and miserable. Wet and little or no sun. Whilst I haven’t got any data for previous year, what’s obvious from the figures for this year is that rather than trending upwards, the average daily temperatures for early April are on a downward slope and, unless we get some decent sun in the next few days, it doesn’t look as though its going to get any better.

This affects my tomatoes. Normally, by now, I’m sure I’ve stopped taking the plants in and out of the greenhouse, relying on the daytime sunshine to leave residual heat in the greenhouse to keep the temperatures above 10C without adding any extra heat. However, in the past week, the temperature in the polytunnel hasn’t crept above 10C even in the daytime and the nighttime temperatures have drifted towards 5C.

Tomatoes don’t like being cold and not being adequately warm at the start will affect them throughout the year. So I’ll have to continue bringing them in and out of the house for a few more days yet. This could mean that I’ve got lots more trays to carry through but I’m afraid I’ve identified the strongest plants and only those will be molly-coddled, the rest will have to tough it out in the greenhouse.

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When should I sow my Tomato Seeds?

I ask myself this question every year. The seed packets say “sow in late winter” (when’s that?) or “late January to March” (more understandable) and, in different years, I’ve tried sowing from early January through until early April.

I think the answer depends upon a lot of variables some of which you can control and some of which you can’t. So lets look at them:

  1. The Weather
    The weather plays a part over which we have little or no control. Tomatoes originate from Mexico and grow best when the temperatures are always above 10C but below 35-40C. They also like light but not too much direct sunlight so juggling the seedlings/plants to give them the best conditions in the variety of external environments that we try to grow them in is a challenge. So knowing when the last frost is in your area and how much sunlight falls on your greenhouse whilst there are no leaves on the trees is something that you need to bear in mind and varies from yer to year.
  2. When/Where are you going to plant them?
    When and Where are related. Tomatoes suffer if their nighttime temperature stays below 10C for more than an hour or so and certainly don’t want a frost (they go purple, struggle and may not every recover). So you shouldn’t plant your tomatoes into their final place until after the last frost. Now when that is depends upon whether you’re planting them outside, in an unheated greenhouse or in a heated greenhouse and where in the world you live. (For me at home, the last frost is the end of May so planting outside has to wait until June, my allotment is on the other side of a north facing hill and the last frost is a few days later). An unheated greenhouse protects the plants and they can be planted a couple of weeks earlier. If you’re lucky enough to have a heated greenhouse temperature is not the issue.
  3. What are you going to do with them after they’ve germinated?
    Germinating tomato seeds is easy. Put them somewhere warm (20C) in decent compost and (depending on the age of the seeds) they’ll germinate in a week or two (the older the seeds the longer they’ll take but if they haven’t germinated in two or three weeks I think you can assume they’re not going to).
    However, once they’ve germinated, they need light and reasonable warmth to encourage them to grow strongly. I’ve found there are three steps:Seedlings:
    Seedlings are from when they first germinate until they’ve got their first true leaves. I sow my seeds in 7cm pots with about five seeds in a pot (perhaps more if they are old seeds which may not germinate). A seed tray will hold 15 pots and so 30 varieties (which is what I aim to grow) can be easily handled. Assuming the weather is reasonable (light & warmth), the seedlings can be carried out to the greenhouse every day and back in every night.

    Once the seedlings have their first true leaves, they should be separated into individual pots/plugs. At this point I carry out the first “cull” of my tomatoes, reducing the number of plants to about three/four of each variety. So now I have 90/120 plants. If they are in 7cm pots, this is 6-8 trays which is less convenient to move in and out of the greenhouse. However, I usually use plug trays which halve the number of trips.
    The plants will stay in the plugs for two – three weeks (its now five weeks since they were sown) and there will be nights when it will be warm enough for the tomatoes to stay out overnight in the unheated greenhouse.

    Small Plants
    Once the roots have filled the plugs, the plants need to be moved to larger pots (7-9cm) where they will stay until they are planted out. I cull them again, leaving myself with twice as many plants as I will need and, at this point, the plants need space & height, as well as warmth and light. However, by late April/early May the overnight temperatures in an unheated greenhouse are unlikely to fall below 10C for very long, so I tend to divide the plants, one set that will stay in the unheated greenhouse no matter what the nighttime forecast and the other half (30 plants) that will be brought in overnight if its going to be bad.

Tomato Seedlings 3 days after sowing


There’s no right answer, only what works for you. Your tomatoes will need about eight weeks from germination to planting out so seeds to be planted outside should be sown later than those in a cold greenhouse which in turn are later than those in a heated greenhouse.

How long you can look after the plants before they have to be planted out depends upon how much space you’ve got that can give the necessary warmth and light.

For me (in the middle of the UK and planting in unheated greenhouses) the answer that works seems to be early to mid March with a period of time molly-coddling the seedlings over night.

I’d be interested in your comments.

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Recipe: Sweetcorn Chowder

This is a fantastic recipe. A rich and creamy soup that's quick and easy to make, using fresh or frozen ingredients.

Its so quick, it's not really worthwhile freezing, you can make it from scratch in the same time as it would take to defrost it.

Ingredients (for 2)

  • Sweetcorn Kernels from one sweetcorn cob
  • 1 medium courgette
  • 1/2 Onion
  • 400ml vegetable (or chicken) stock
  • Oil & 50g butter for frying
  • Optional - double cream to serve
Sweetcorn Chowder


  1. Chop the onion & courgette - they don't need to be too small as you're going to whiz it with a stick blender when its cooked;
  2. Heat up the oil & butter in a saucepan and fry the onion until its soft (not coloured);
  3. Add the courgette & sweetcorn kernels and fry gently for 3-5 minutes;
  4. Add the stock and cook until the vegetables are tender;
  5. Season - we don't add salt, the butter has enough in our opinion;
  6. Blend with the stick blender until its rich and creamy. The texture is up to you, if you want texture don't blitz it for too long.

There you go, 15 minutes from start to end and a rich, creamy, warming soup.

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Waterbutt in the Polytunnel – A final conclusion

As I’ve said more than once (here and other places) I’ve been intrigued by the question of whether putting waterbutts filled with water into the greenhouse/polytunnel can beneficially affect/improve the temperature in the polytunnel. To try and come to a conclusion, I built a Raspberry Pi temperature sensor with four sensors (see here). I put one outside the polytunnel, one inside the polytunnel, one in a small watering can of water and one in a waterbutt. For security I then copied the resulting file to a centralised Raspberry Pi over the network (like this) and finally copied the file to Dropbox so that I could read it elsewhere (like this).

All of this was done through a series cronjobs on the various machines.

These sensors have given me the ability to accurately measure all the temperatures and make some observations which go like this:

  1. The temperature in the polytunnel is most affected by sun. When the sun is shining on the tunnel, the temperature rises rapidly. If there’s no sun, the temperature in the polytunnel is the same or perhaps up to 0.5C warmer than the temperature outside the tunnel;
  2. The rate of water temperature rise is more affected by sunshine than the temperature in the polytunnel (this is a bit more difficult to prove as the main cause of rises in the polytunnel temperature is sunshine);
  3. The temperature of the water rises and falls more slowly than the temperature in the polytunnel. The water temperature changes proportionally to the difference between the temperature in the polytunnel and the temperature of the water.
  4. The temperature of the water becomes static at -0.3C, regardless of how much colder the polytunnel gets;
  5. The watering can (5L changes temperature more quickly than the waterbutt (200L).
  6. The temperature of the water is (in general) higher than the temperature in the polytunnel from 16:00 to 08:00 (when the sun is not shining)


  1. Having a waterbutt of water in the sun in the polytunnel must make a difference. The water will give out heat when the polytunnel is colder than the water;
  2. However, the effect is primarily driven by the number of hours of sun.

So, overall, the conclusion is (at least for the months of December, January & February, putting a waterbutt in the polytunnel has no appreciable of beneficial effect. The days are too short and there are to many sunless days.

This doesn’t mean that March and April won’t benefit as the number of sunny days increase and the nights get shorter. Let’s see.

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Recipe: Chicken, Swiss Chard & Noodles

This recipe is a new one for us, because I'm wheat free(ish) and my better half isn't, we're always looking recipes that can be created as both.

The original recipe called for spinach. Swiss Chard is easier to grow and available from early in the year and (in our opinion) better.

Ingredients (for 2)

  • Noodles (egg or Rice Noodles if you're Gluten/Wheat Free);
  • 2 small chicken breasts thinly sliced;
  • 100g mushrooms;
  • Small Bunch Spring Onions;
  • 1 Clove of Garlic;
  • 3 tbsp Oyster Sauce;
  • 100ml Chicken Stock;
  • 100g Swiss Chard (or more - as much as you like);
  • 0.75 to 1.5 tsp black peppercorns crushed (for heat);
  • Salt & pepper to season (optional).


  1. Cook the Noodles;
  2. Fry the chicken in the oil over a high heat to brown and cook through. Add the onions, garlic, mushrooms, crushed peppercorns and cook for about two minutes stirring as you go. (The quantity of peppercorns defines the heat of this dish, we don't like it too hot so 1 tsp is enough. Also remember to crush them up properly, finding -and chewing - bits of pepper in your teeth after you've finished isn't entirely pleasant).
  3. Add the Oyster Sauce and stock;
  4. Add the swiss chard and cook until wilted (1-2 minutes);
  5. Add any seasoning you think you need (we don't add any extra at this point);
  6. Serve on the noodles.
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