Thursday, 25 June 2015

Polyculture, the way forward?

There follows an in-depth philosophical overview of the nature of vegetable gardening. There is a lot of detail about the principles I follow. It undoubtedly poses more questions than it gives answers. For this I apologise, but I am feeling a bit confused when it comes to how to manage my vegetable plot. It is time for a re-evaluation. Not that anything is going dreadfully wrong.

Every time I visit the Green Backyard in Peterborough I come away inspired. When we were last there making our rocket stoves, I looked around the vegetable garden and it looked nothing like mine. Notwithstanding the amazing sculptures and willow weaving which emerge every time you turn a corner, the vegetables themselves looked different. There is clearly a plan of sorts in effect, but it looks all cottage gardeny. Love-in-a-mist and salsify dot themselves around, along with marigolds, nasturtium, rosemary, sage, poppies. Every space has been filled, but just as often it would seem accidentally.

This is close to the image I had in my head of what I wanted my veg plot to look like, but I've strayed a long way from it, lured by neat lines and rotavated empty spaces. One bed in particular caught my eye. For just a few months ago it was a strawberry bed, before we did this to it!

Digging out the clay for the cob oven
But now it has been backfilled and planted up with black kale, peas, chives, courgettes, French beans, lettuces, potatoes. The plants still had plenty of room to grow into and nothing had yet self-seeded into the bed, so this was just about the only bed with visible bare earth.
But hang on a minute! What's happened to the rotation? I see plants from all different groups in the same bed.

Rotation is the keystone of organic gardening. The basic theory is that similar plants take similar nutrients from the ground, while others actually enrich the soil. So if you rotate your crops then you can control the soil to the benefit of each plant group and the soil will not become depleted. You top up the goodness with plenty of compost and manure before the spuds and the brassicas (green, cabbagey things) go in. The root crops go into soil which is not too heavy in nutrients, as they don't need them. The beans go in before the brassicas, as they fix nitrogen in the soil.
That's the theory.
A further benefit is that pests and diseases don't get time to establish in the soil, as each year they find a different type of crop in their patch. This is especially important when it comes to the brassicas.

With a bit of planning, this system is nice and straightforward. Crops go in, crops come out. And every year you dig and rotavate the whole lot, add your organic nutrients and let the chickens in to clear the ground of creepy crawlies and to further enrich the soil. Almost as simple as it sounds.

As well as rotation, there are other gardening principles which I have tried to embrace, most notably companion planting. Some plants prefer the company of others, but most importantly, some plants deter and confuse pests. Herbs are good at this, as are marigolds (calendula and tagetes) and nasturtiums.
A lone tagetes tries to protect the surrounding turnps
There are other principles which I don't follow, such as no-dig gardening. In this version, you don't dig! Sounds ideal! Instead you just keep adding oodles of compost to the surface, so never treading the soil down and never bringing all the weed seeds to the surface, which can be a big problem when you have just rotavated the ground in spring.
I can understand this, but think it works best on a very small scale garden with maybe just a few small beds. Even then, I don't actually think many gardens would have the capacity to produce enough compost to sustain this system. I suspect you either need enough land to bring in compost materials from elsewhere or, in urban gardens, people end up spending a small fortune on bags of compost, which somehow feels wrong to me.

Anyway, as much as I can I avoid treading on the soil - hence a system of small beds so that much can be reached from the grass paths. But gradually I have joined the beds, as the effort of mowing and edging the intricate system of paths became unmanageable and there is no way I can afford or desire to turn all my paths over to bought in aggregates. I must admit though that the volume of weed seeds dragged to the surface by the spring rotavation is a problem and they often overwhelm the emerging crops as they race ahead of them. There's only so close to your crops that a hoe can go and only a certain amount of hand weeding that my back can take.
In general, if the soil is dry, I hoe. If it is wet, I pull.

So, that's the theory over and done with.
Now for the practical. And I'm afraid it begins with a list of problems I have encountered, which have led me to slowly move towards bigger beds with neat lines of crops with bare soil between. It's all very ordered and, if you leave enough space between rows, you can get down them with a small rotavator which makes the large scale part of weeding a doddle.

I originally started out trying to combine gardening by rotation with companion planting, but found that it was tricky to hoe between the rows, or to get the companion plants to mature in time to do their job. If I planted marigolds in with my potatoes, they got between the rows and stopped me cultivating by any other method than by hand, which is just not practical on a large scale. Worse than that, maybe they kept certain pests and diseases at bay, but they stopped the airflow between plants which is so important in the battle to stave off blight, a pestilent fungal disease which carries a much greater threat than all other diseases and pests put together. One further problem, the calendulas needed to get going early so that they were healthy plants bursting with flowers in time to have a positive impact on the spuds. But the easiest way to get the spuds in the ground is just to rotavate or dig the whole patch in preparation for the seed potatoes going in. You just can't be working around small emerging marigold plants.

The potato patch. Pretty much bare earth for up to 9 months of the year

Another good idea for growing potatoes is to grow a couple of horseradish plants in with them. Just a couple will do. I tried this, taking cuttings from my horseradish patch, but they only really got going in their second year, when the spuds had moved on! I decided to leave them in the ground so they would be there next time the spuds came round, in a couple more years. But most of them got rotavated in the winter, as they had retreated below ground. Even if I had marked their location rotavating around them would have been a pain. And besides, I would need to plant one in every bed, as eventually every bed would be host to potatoes.

So I have decided to abandon companion planting in the potato patch. It looked prettier and felt right, but it was just not practical. Shame.

Calendula marigolds are excellent companions for most plants
I tried growing carrots mixed in with annual flowers too. These are supposed to confuse the carrot root fly and I figured it would look very attractive, a wild flower patch which also yields carrots. Trouble was, the flowers outgrew the carrots, which are slow to get going, then crowded them out. Besides, I ended up being more confused than the flies when I couldn't find the carrots in amongst the mass. At the end of the year, when the flowers had died down, I found carrots in the ground when I was rotavating. Most of them got shredded as the tops had died down and I couldn't find them before the blades of the rotavator. I could have followed the original lines, but the crop was too scant to do this as the young carrots had been overwhelmed. To make matters even worse, they were riddled with carrot fly!
I tried some more practical companion planting, growing my rows of carrots between rows of onions and garlic. This had more effect keeping the carrotfly away, but I have still found it easier to grow my onions separately, in their own bed each year. I just rotavate their patch to a fine tilth, plant the sets, keep it all well weeded and, come late summer, pull them all out again leaving a nice neat patch of bare earth ready to be worked in the autumn and left bare in the winter, for the chickens to pick over. Last year I decided to let self-seeded nasturtiums grow in amongst the onions. They grew too well! The onions got lost underneath and many of them ended up rotting off. Lesson learned. So now the onions grow on their own and the carrots grow in neat lines behind the protection of netting. Besides, the onions and garlic need fertile soil and the carrots don't, so growing them together does not really work in that sense. Except that I am now reading that it is not fertile soil that makes carrots fork after all. It is hard and stony ground, which mine is not. I must say, it is very rare that a carrot forks on me. A lot of the parsnips did last year, but I think that was because I didn't prepare the soil deeply enough. Mind you, I read so much contradictory advice that I never really know what to believe. So many of the old gardeners' ways are now superseded by modern methods, but I'm really quite confused over how much of that old wisdom was just wrong advice handed down from generation to generation and how much was the incredibly valuable benefit of experience. I'd like to think the latter, but then you look at the over reliance on nasty chemicals which I guess comes from the post war years and you begin to wonder.
I have read too, that the best way to maximise the nitrogen collected by bean plants is actually to uproot them and put the whole lot on the compost bin, in which case you can then eventually return the nitrogen to whichever part of the plot you wish. So bang goes the idea of leaving those nodules in the ground to give nitrogen to the brassicas which follow the beans.
It's fair to say I am feeling more than a little confused. I think I have read too much!

Companion plants get in the way... Brassicas don't need to follow beans... Carrots don't split in fertile soil...Small beds are unmanageable on a large scale...Are all my principles going down the swanny????

On the other hand, I am getting good potato harvests. For the first time this year I am getting success with my carrots. I am (almost) on top of the weeds thanks to straightforward rows and an annual winter clearance of the soil.

Yet something feels wrong. Much as the OCD part of me likes the neat rows and clean ground between them, the creative, nostalgic part of me yearns for that cottage gardeny look and the radical side of me wants desperately to believe that there is merit in companion planting and working with nature rather than constantly fighting to stave it off.
Feverfew growing up against the polytunnel

On the one hand, I don't want the soil so full that there is no ventilation. Also I don't want to be weeding by hand all the time. But on the other, it feels as if the soil is bare for half it's life and that having nothing between neat lines of crops is just allowing the soil to dry out and become sterile.

The vision I had when I was planning everything was one of vegetables accompanied by herbs, fruit bushes and perennial flowers, as well as self-seeding colonisers such as California poppy, nasturtium, love-in-a-mist, angelica. And I wanted comfrey and horseradish and lovage dotted around. I wanted to let plants go to seed and surprise me the next year.

But as soon as you put a rosemary bush, a redcurrant, some horseradish root and some flowering bulbs into a veg bed, it becomes impossible to rotavate it. And with that it becomes impossible to maintain a well-ordered rotation.
I've never managed to be organised enough to grow green manures properly, but this year I am planning to. Imagine trying to dig or rotavate these back into the soil whilst trying to avoid various plants dotted around the bed. Impossible.

So where is this blog post going? Is it here just to confuse, to pose questions and highlight obstacles?
Don't worry. There is an answer coming up, of sorts.

I came upon a system which sort of gets the best of both worlds. I would continue with the rotation and rotavation. But the new, bigger beds and efficient rows of crops have meant that I can spare some beds for other purposes.I toyed with the idea of leaving some fallow, onto which all my compost would go throughout the year. This is a component of no dig gardening and I may incorporate this to some extent in the future.  But instead I decided to allow myself the luxury of having whole beds bursting with colourful flower mixes scattered around the veg plot. One in each quarter of the rotation.
Last year's bee mix which I have
allowed to come back naturally
This would allow me to have neat, ordered rows of vegetables but the appearance of the whole would be much more aesthetically pleasing and more wildlife friendly too, especially for pollinators.
It worked quite well last year, but I still have large amounts of bare soil. By the time the early potato beds are being cleared, the bean beds are only just getting going.
There was none of this bare earth at the Green Backyard. As the potatoes were coming out, the beans (or something else) would grow into the vacant space. And what about those mixed crops? Surely not the product of complete gardening ignorance?

So I asked. And in the reply I heard words like "polyculture" and "successional growth".
I got home and started looking these up and, to be quite honest, I found very little information on them. Polyculture seems to be an area of permaculture, which I have never really got into. It seems to me to work best in warmer climes.
Anyway, I eventually found titbits of information. The principle is that you try not to grow any plant next to another one of itself. That way there is no obvious target for pests, which are confused by the array of colours and shapes. It is also more difficult for diseases and fungal threats to jump from plant to plant. That all makes sense, but what happens to your rotation, that integral principle of organic gardening? And how do you stop the weeds taking over? And how do you protect your peas and brassicas if they're dotted all over the place?
brassica bed - the whole rotation system seems
perfectly designed for growing brassicas
I understand all about working with nature, but I have come to realise that the ideal is not always practical. I actually don't really want to find caterpillars in my caulis or slugs in my lettuce. Nor though, quite definitely, do I want my food or garden polluted with nasty chemicals. I suspect that when it comes to it, even with my current system, I am actually working with nature a lot more than most gardeners.

I eventually got hold of a book with a couple of pages devoted to polyculture.The answer to my question on rotation was simpler than I thought possible. It basically said that, if you dot plants fairly randomly (even if there is a planting pattern in each bed), you are unlikely to end up growing the same type of crop in the same place year after year. Simple! Okay, you may (will) get some crops going into the same ground, but it will not be on a large or long enough scale to create any significant problems. You are far more likely to attract pests and diseases by growing monoculture clumps. If you're still really hung up by wanting a strict rotation in place, you could always go to the effort of planning the whole plot out square foot by square foot. Depends how much spare time you have on those long winter nights, I guess.
I think, though, that I am more attracted to the former. That way, plants can be allowed to self seed randomly too. If there are too many, they can always be taken out, or moved to where you want them.

Polyculture also has a unique approach to controlling weeds. Firstly, it's basically a minimal digging system, which means that your perennials and self-seeded waifs and strays can escape the ravages of the rotavator. Instead, you scatter the ground with salad seeds (lettuces, radishes, mustard) mixed in with some seeds of plants which take longer to mature. You then cover it with a layer of compost. The idea is that the salad plants mature quickly and fill the ground. As you pick them, other crops mature to fill their space. Successional growing. (Not quite the same as successional planting, which is where you sow a crop every couple of weeks so they don't all mature at eh same time).
Now, I am not quite so convinced by this. Firstly, I would have enough lettuces, leaves and radishes to feed a small army. Secondly, even if I didn't turn the soil, my fenland soil is so fertile that I really don't think I could hold the weeds at bay. In a small vegetable plot, I could hand weed, but on a larger scale this would not be practical.

Anyway, apart from that, I really like the idea of polyculture. It is sort of what I was aiming for in the first place, except that it introduces the idea of mixing the crops.
So I have decided to experiment with one bed, where all my spare seedlings have gone. I have even scattered some salad seeds in a small area.
My suspicion is that I will end up with a mix of growing methods. Each quarter of the veg plot, which is arranged like a wheel, will still have sections devoted to roots, spuds, brassicas or beans 'n' peas. I will keep the beds devoted to flower mixes. They can stay there from year to year. But I will introduce a few polyculture beds too.
Hopefully the systems won't clash. That way I can continue to experiment and the best system will, eventually, make itself apparent.

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