I am having to make changes to my vegetable growing areas in order to reduce the time that it takes to manage. I currently have two areas in which I grow vegetables and grains, covering over a quarter of an acre. This has been difficult to maintain whilst at college, and will be much more difficult when I start at university. One of the principles of Permaculture is to “Creatively use and respond to change”, so that’s what I’m doing.
Sometimes it’s funny how things turn out. I have not been a fan of the ‘garden polyculture’ strand within permaculture. I think that it’s ok on a small scale, or where there is a lot of free labour available for harvesting, but it has never struck me as a way to grow significant quantities of calories. Strangely I seem to be coming back to the idea. It all started with confirmation of the yield increase from a grain legume combination. Not really a true polyculture, more of an intercrop, but the basis of my small scale grain growing experiments. Things have moved on a bit since then. Please note that I’m not going to be giving details of all of the plants that I am using in my experiment, or references for the information that has got me to this point. I want to be sure that it works, before publishing the results. There will however be plenty of links to help you think about your own polycultures, or cover crop cocktails.
I have been intrigued by the idea of a hotbed for years, but the trigger for this project was reading ‘Hot Beds’ by Jack First. This book is a great little resource, packed full of information on how to make a hotbed, and what to grow in one once made. Having put up a decent sized polytunnel (hoop house) last Summer, I’ve been waiting for the right time to build a hotbed. According to Jack, the right time for a full depth bed is the end of January, so that’s what I have done. This post contains lots of pictures of the hotbed, along with some text. However the construction for an outdoor bed is a little different, and if that’s what you’re looking for, you probably need the book.
A hotbed uses the heat from decomposing organic matter to raise the temperature of soil in an enclosed space, in order to extend the growing season. One reason for that is that by the time that the last frost has passsed, so have a lot of days with long day length. For example our last safe frost date is normally the first week in June. That is only 2 weeks before the Summer solstice, after which daylength starts to shorten again. By provided a warm and sheltered environment for growing crops, a hotbed will let me make use of that additional sunlight.
Jack recommends a hotbed size of about 6 ft x 6ft (180 cm x 180 cm), to provide a growing space of about 4ft x 4ft. The growing space has it’s own frame partly buried in the hotbed, with the extra space all round helping to prevent heat loss. The depth of the hotbed determines how early to start building it. 2 ft -2 ft 6 ins (60 – 75 cm) of horse manure, and wet stable bedding (straw) is supposed to maintain warmth through until the weather is warm enough.
There is a good picture of how a hotbed could be made on the page link below, about half way down the page. Spring gardening Tips.
The central bed in my polytunnel is 5 ft wide, made 18 inches tall with timber planks. The bed runs North to South, so I decided to make the hotbed at the Southern (entrance) end, to get the most from the low, early season sun. That section of the bed had settled since the Summer, and was about 6 inches below the level of the planks, so I decided to remove another 6 inches of soil, and then build a 2 ft deep hotbed, by adding another 2 planks. This would give me an overall bed size of 6 ft x 5 ft, 2 ft deep. The two pictures below show the bed just before all of the soil had been removed.
The soil that I removed filled 8 dustbins, I knew that I would need about 2/3rd of the soil to put on top of the manure and straw mix. This gives a good growing medium for seeds. The remainder will be used as the base for my seed and potting mix.
After the soil had been removed, I built up the hotbed in layers. My horse manure is given to me without bedding, so I alternated a layer of manure with a layer of poultry bedding. The bedding that I use is shredded Miscanthus. Shredding exposes more surface area to microbes which could lead to the bed heating up, and cooling down too quickly. The decomposition in a normal bed is slowed by compacting the materials. This restricts oxygen, which reduces microbial activity, and therefore slows everything down. To try and slow the process down further, I added a little more bedding than I would have done with undamaged straw, and made sure that the layers were well compacted. I’ll monitor the temperature this year to see how successful that is.
The picture above shows the first layer in place. As the bedding was dry, I watered it, and added urine, seaweed, comfrey concentrate, and the liquid from my wormeries. These additions were to improve the overall nutrient availability, and to add some extra nitrogen. This isn’t something from the hotbed book, but seemed like a good idea. However the extra nitrogen may speed the decomposition up, and make it too quick. I’ll have to monitor that. The picture below shows the hotbed after an extra 12 inches of planking had been added. The lower plank is full length, and the top one is only the length of the hotbed. I did it this way as I always have a surplus of compost, and so I have decided to raise the whole of this bed ( 40 ft x 5ft) by another 6 inches. I’ll stagger this, building a new hotbed each year, moving back along the bed.
The picture above shows the hotbed before the additional planks were added, whereas the one below shows it after all of the timber was in place. If you look carefully at the the picture below, you can see the three levels of timber. The short plank for the top layer, which steps down to a long plank added to the existing bed. Beyond that the bed sides drop again to the original level.
(The black corrugated bitumen is there to prevent a passionflower from being buried by the manure/straw mix. The material should shrink by around a half, so the bitumen can be removed when the hotbed is taken apart.)
The change in levels can be seen better in the next picture, taken from the opposite direction.
The plank to the left of the plants has been added to raise the height of the whole bed, and there is a short plank raising the height of the hotbed still further.
The picture above shows the last but one layer of the straw and manure mix in place. Originally I had intended to build the hotbed the full 2 ft deep, and then add a 4 inch layer of growing medium. The depth of the hotbed determines how long it will remain warm for. 2 ft roughly equates to three months of warmth outdoors. However I started to run short of horse manure. As I’m building the hotbed inside a polytunnel, I’m happy for the bed to cool down slightly quicker, as the protection given by the polytunnel should compensate for that.
The picture above shows the compacted top of the manure and straw mix on the left, and the 4 inch layer of soil that I added on the right. The soil is from the stuff that I removed at the beginning, but sieved. I put the larger lumps at the bottom, and the finer soil on top. Both can be seen in the picture. The sieved soil should give me a better medium for seed sowing.
The picture above shows the finished bed. The round disc is the top of a compost thermometer, which is measuring the temperature in the bottom half of the hotbed (18 inches below the surface). I have two plastic cold frames that were too flimsy for outdoor use. These will sit in the center of the hotbed, and will help to create a warm and protected environment for my early vegetables. The mild Winter (so far), and generous growing of salads late last year, has meant that I already have a surplus of early salad. So I’m going to try growing some tender plants, French beans, and sweet peppers, as well as some extra spinach and rocket (aragula).
Monitoring Hotbed Temperature
When first built, less than a week ago, the temperature was 11 C, roughly 6 degrees above the ambient temperature at the time. The temperature has since climbed to 18 C. I now need to monitor the temperature change. Planting or sowing starts once the temperature steadies, or starts to decline. In order to get a head start, I have sown some of my first batch of plants in modules, in a propagator.
Once the hotbed is ready for planting I’ll post an update.
I’ve been selecting rye for seed, and decided to make the activity more productive by doing some simple observations, and measuring yields.
Saving my Rye Seed
I recently read an old article that suggested that grain taken from the middle of the ear produced better and higher yielding plants. This article on how to rejuvenate crops describes the process. So as I was preparing seed for sowing I thought that I would use this and select that seed. I have ten bundles of rye, so cut 5 heads from each bundle to use. When cutting I chose heads that were long and fat with seed. Part way through I noticed that there was a noticeable difference between the thicknesses of straw where the head attached to the stalk, so decided to restrict myself to the thickest straws. I hope that this will increase the bulk of straw over time.
My small scale grain growing experiment has reached the end of year two, having grown and harvested, rye, spelt, and wheat. I’m almost ready to start sowing the grains for year three, and thought that I would record my results and observations here.
This is the rye and spelt before harvesting. The rye was even more impressive than last year with most of the grain over six feet in height, and some reaching 8 feet tall. I started harvesting a little before I thought that the grain was ripe as I was experiencing a lot of bird predation. I had pigeons eating the spelt, and smaller birds eating the rye.
The picture above shows some of the evidence. The pigeons land on top of a bundle of grain, forcing it towards the ground where they can get to it more easily. Once down it then becomes easier for rats and mice to get at it too.
I was a bit concerned that with harvesting it a bit early germination may be reduced, but I was preparing the beds for sowing today, and there was grain sprouting where some had been missed by the birds.
This is my High Tech measuring system to get a rough idea of yields. I simply stuff the grain into the rubbish bin until I cannot get any more in, and then tie it up into a bundle. Not that scientific, as it only measures the straw, but ti gives me a rough comparison between different crops and systems. That’s not too much of an issue for me, as the straw is as important to me as the grain is. it will be used as poultry bedding, and then returned to the growing area to help build fertility. Were I more concerned with money, the rye straw is perfect for making skeps, for which beekeepers pay a lot of money. The picture also gives you an idea of just how tall these grains are compared to the modern ‘vertically challenged’ grains grown conventionally.
Small Scale Grain Growing yields
It’s difficult to describe or assess what your yields will be when you are growing grains on a small scale, so I thought that |I’d show you my yields in pictures.
The picture above shows a bed of 100 sq feet (4 ft x 25 ft). (In theory this bed would be 5 ft wide, but the high nature of the bed won’t allow planting all the way across). This is the standard size bed for the Grow Bio-intensive system. it’s also the right size to allow comparisons between fertilizer applications (grams per 100 sq ft bed is roughly equivalent to lbs per acre). The picture below shows the yield of spelt taken from it.
The 100sq ft bed produced four ‘stuffed bin’ sized bundles, which is pretty cool. Once these have been threshed and winnowed, I’ll start to get an idea of how much grain i get from each bundle, which will be much more useful.
The overall yield from this year’s grain growing was 30 of these bundles, with roughly equal amounts of each of the three grains.
The only direct comparison that I did was two roughly equal sized beds of wheat. In one the wheat was was spaced at 12 inches apart, and in the other the rows remained 12 inches apart, but the grain was only six inches apart within the rows. of the two, the smaller spacing yielded fractionally more than the wider spacing. 3 1/4 bundles as opposed to 3 for the 12 inch spaced grains.This used twice as much seed, and was harder to weed, but seemed to resist lodging better. The recommended spacing for the System of Wheat Intensification method is 8 inches, and perhaps the results of this comparison bear that out. The difference in yield for such a small plot is not significant, but it will be interesting to repeat this a few times to see if the difference remains over a number of years.
One of the benefits of small scale grain growing is the ability to observe closely what is going in with each grain. On a huge scale you can only look at little patches of the whole picture, whereas I get to see everything in great detail.
Ergot is a problem in chemical free rye, but I only found one infected grain. Earlier in the season when the weather was damp it looked as if more were infected, but the grain seems to have fought it off on it’s own. There were tiny patches of black on the very ends of a couple of grains, but the grains themselves were healthy. The weather may have helped, but it’s reassuring to see a strong, healthy rye plant.
There was very little weed amongst the grains themselves. The picture below shows one of the rye beds after harvest, and you can see for yourself how clean it is.
The next picture shows a bed of spelt after harvest. can you spot the difference?
Well I hope that you can see a lot more green in the second picture. Both of these crops were module sown, and I added some wild white clover to the modules. On planting out, both crops had a small amount of white clover around the base of each plant. As you can see from the pictures. This clover has grown reasonably well with the spelt, but very little has survived with the rye. Some of this may be due to the extra shade cast by the rye, which was taller. Another possibility is that the rye is a bit allelopathic, chemically suppressing it’s rivals. If that’s true it could be really useful to help combat spring germinating weeds, possibly in an organic vegetable system. That’s in addition to the yield of grain, masses of straw for fertility building, a massive root system, and a late sown crop to help mop up Nitrogen after the harvest of an earlier crop. Not a bad set of reasons to incorporate small scale grain growing into your own system. To test the allelopathy I’m going to swap the crops grown on these two beds this year.
Growing Grains in 2013/2014
The next year’s small scale grain growing experiments are similar. The single wheat variety will be replaced by a mixture of six winter wheats, grown as part of the Permaculture Association’s ‘Sustainable Grain’ project. This is a research project to develop a sustainable, small scale grain growing system. Now that I have a good supply of grain and seed, I will grow less of the rye and spelt this year. Sowing just enough to maintain a fresh supply of seed. I want to grow out some Rivet Wheat that I was given, mainly to see what it looks like, but also to keep the seed fresh. I have to read up in chemical free methods to clean the seed from Bunt. I was told that coating in mustard powder, or dried milk works, but I’d like to look into that over the next few days before deciding whether to risk using this seed or not. I also have two different varieties of oats to grow next spring. One variety is Naked Oats, and the other Black Oats. The Black Oats may also have some allelopathy so could be potentially useful. Although oats are normally a spring sown crop here, the Black oats are supposed to be really tough, so I might broadcast sow a small bed soon to see how much survives. Even if none does, it will suppress weeds first, mop up nitrogen, and then winter kill. acting as a non hardy green manure crop. There is a lot that you can do with this small scale grain growing, and I intend to try as much as I can.
All of the best