Apologies to website subscribers who received a post called ‘Donating’ earlier today. This was meant to go up as a new page rather than being published as a post. The news that I meant to put out today is that my 2016 seed list is now on the website as part of a redesign in which the old ‘shop’ page has been replaced by a new one which takes more of a gift-economy approach. You can read all about it at forest garden seeds.
There is one kind of plant that really doesn’t belong in a forest garden, and that is grass. When I got my allotment, it had the traditional layout of bare soil beds with raised grass paths between them. The old boys actually seem to enjoy maintaining these structures, mowing the tops to perfection and deploying a range of implements that a hairdresser would be proud of to keep the sides in trim. If this is neglected for even a short while, the grass flops over the sides, first making a perfect habitat for slugs then starting to grow into the beds.
I decided that no matter how much work it took to replace the paths with something more sensible, it couldn’t be more work than keeping the things. The turves were dug up and piled, upside-down, to compost. I now have three main walking surfaces in the garden. The short stretch that bears the most traffic is slabbed. The other main paths are all woodchip and across some of the beds I have walking boards.
Woodchip is a great path material for several reasons. It is particularly high in carbon which makes it a very infertile medium. Woodchip should never be dug into the soil or, in my opinion, used as a mulch on top of beds, since the soil bacteria pull nitrogen out of the soil to help them break down the carbon, robbing your plants of essential fertiliser. Using it on paths turns its downside into a virtue. If plants do seed into a bed of woodchip, its soft, granular nature means that it is very easy to hoe them off. If you have ever tried to hoe gravel you will understand what a benefit this is. Finally, it is usually a cheap, easily available material. We just get the City Council, who produce mounds of the stuff and are delighted to get rid of it, to drop us off a heap every year. This year’s load turned up last week.
To make the woodchip paths, I dug out about a foot of soil and used it to build up the beds. I lined the bottom of the trenches with any cardboard and bits of old board that I could scavenge, but didn’t worry about this where nothing came to hand. Then I simply filled them with as much woodchip as I could lay my hands on. They have to be hoed in the spring and topped up about once a year, but neither job is urgent and they can be done whenever there is time.
As well as being much less work, woodchip paths are far more robust than grass ones, something I’m appreciating in the current wet weather as the grass paths are trampled to mud while the woodchip ones show no ill effects at all.
Walking boards are even simpler. I only really use them in the annual parts of the garden as there is no problem in stepping on the soil in the perennial parts. They are simply boards laid down on top of the soil to make a path. They serve two main purposes: stopping soil compaction and acting as slug traps. If you turn over any piece of wood lying on the ground you’ll see what I mean: the slugs retire there during the day and can be collected easily. The boards also provide habitat for beetles and centipedes which eat slugs and their eggs, so the slimy molluscs get a double whammy.
Here’s the end result. The forest garden has been thoroughly put to bed for the winter, with a mulch of leaves on the growing areas and a new layer of woodchip on the paths.
I’ve learned a lot of things in the course of trying out permaculture and forest gardening. Some of them I’ve then had to unlearn again. Here are my top four forest gardening myths.
Practically every forest gardening book you can find will tell you that you need ground covers: plants whose main function is to cover the soil. They are usually aggressive spreaders like mint and tansy that also attract insects and are said to benefit the garden in some rather intangible way through the aromatic substances they release. Sometimes they can be plants like Rubus pentalobus, a bramble relative that carpets the ground thickly and produces a token yield of small fruits.
I can see where the ground cover idea came from. If you have a large area and are mostly interested in the tree and shrub products, then perhaps all you want from a ground layer plant is that it will outcompete the weeds and save you some work (raising some interesting questions about how you define a ‘weed’). But in a smaller area there is absolutely no point to ground covers: you want to fill the whole ground layer with productive plants and fertility-builders.
In my experience ground covers are completely unnecessary for attracting wildlife: the whole point of a forest garden is that the productive plants get to go through their entire annual cycle of growing and flowering and most of them are excellent wildlife plants in their own right. I am also a firm unbeliever in magic ingredients like aromatics in ecosystems: the only magic ingredient is diversity.
Straight lines are bad
Funky, curvy lines almost seem to be a defining feature and article of faith of permaculture, which is the route by which a lot of people come into forest gardening. However, at the risk of sounding very… well… straight, I have to say that there’s a lot to be said for planting in straight lines. One reason is that it makes hoeing much easier. There isn’t a lot of weeding to be done in a forest garden, but there’s still some, and running a hoe down between rows is by far the easiest way to do it. It also helps you to avoid hoeing down your crop plants. A lot of perennial vegetables die down during winter and it is very disheartening to slice the tops off them just as they should be bursting into new growth. Having them in straight lines helps you remember at least generally where they should be.
Another reason for hoeing is that sometimes you want to thin out your plants, particularly with the self-seeders. I neglected to hoe lines through my leaf beet this year and was rewarded with a patch of scrawny plants that were more interested in producing stem and racing each other for the light than they were in producing fat, juicy leaves for me to eat.
Finally, straight lines make for good access. Mandala beds may look great when they are first laid out, but regrettably a New-York-style grid is probably the best compromise between getting round the garden, getting access to individual beds and not taking up too much space that you can get.
A mature forest garden is often said to be a ‘no-work’ system. If only! However, there is a kernel of truth in this one. There is far, far less work involved in digging and weeding a well-planned forest garden than there is in an annual veg plot. However, there tends to be more work in the harvesting. With annual vegetables you generally lift the whole plant; in a forest garden you pull bits off it, which takes more time.
I would change ‘no work’ to ‘better work’, as I don’t know many people who prefer weeding to harvesting. Perhaps the biggest advantage in work terms is that the the work schedule in a forest garden is much more forgiving. In the veg plot, you generally have to weed those seedlings NOW or you’ll lose them. In the forest garden you can usually leave a task til mañana, or indeed next month, with little harm done.
Bare soil is the devil’s work
A quick walk round any forest should be enough to dispel this one. You certainly want to keep soil disturbance to a minimum and only those who like thankless work would try to maintain areas of bare soil for the sake of it, but there is no need to obsessively try to cover every square inch with ground covers and mulch. Woodchip is for the paths and the paths only and other, more nitrogen-rich mulches are a useful bonus if you can get them – a way of adding fertility to the soil – not a requirement.
Forest gardening is all about growing plants in some degree of shade, and plant books and websites will usually give you a helpful indication of whether a plant prefers sun, light shade or deep shade. Less obviously, the same plant can often tolerate a wide range of shade conditions, often becoming almost a different plant in the process. When I get a new plant to experiment with, if at all possible I plant it out in a wide range of shade conditions to see how it fares. Not all shade is the same: morning shade is different from evening shade for instance, so it’s worth experimenting a bit to see what your plant really likes.
I was reminded of another benefit of this approach recently when I found this wild garlic, growing in the most shady part of the garden under the privet hedge that forms my border with one of the gardens that back on to the allotments.
Wild garlic really hates hot sun and most wild garlic round here curled up and died a couple of months ago (which come to think of it, was about the last time we had hot sun). The one in really deep shade, however, has remained in leaf, despite the fact that it has flowered and set seed (you can see the seed heads) on about the same schedule as all the others in the garden. This is quite a common effect of differing shade and you can use it to extend the season of all kinds of plants.
Spinach used to be a noun, a particular plant, Spinacia oleracea: a pleasure to eat but a pain to grow, requiring lots of feeding and watering and running to seed the minute you look at it. Now, in the forest garden, it has become a verb, a way of cooking, something you do with a great variety of leaves.
Here’s my spinach recipe. Gather a mixture of wild garlic (Allium ursinum), leaf beet (Beta vulgaris), perennial kale (Brassica oleracea ramosa), red mustard (Brassica juncea), hedge garlic (Alliaria petiolata), Good King Henry (Chenopodium bonus-henricus), salsify (Tragopogon porrifolius), pea (Pisum sativum), Hosta and mallow (Malva sylvestris) leaves. Give them a quick wash and chop roughly.
Now fry an onion and some garlic (or any of the other alliums from the forest garden, but I won’t go there just now) in a large pan. Then throw the leaves on top, sprinkle on a little salt, cover and cook slowly. The jucier leaves will cook in their own juice if there is still some water clinging to the leaves, but with the others you will need to add a tiny bit of water.
To my taste, the result is simple but delicious. I also love the texture. Frozen spinach from the shops goes to a horrible mush, but the large leaf size in this recipe gives it a firmness and integrity.
If the taste isn’t enough, spinach is, as your mum no doubt told you, very good for you. Apparently spinach got its near supernatural reputation for iron content and strengthening properties (think Popeye) when an early table of the nutrient content of different foods accidentally slipped a decimal place, giving spinach ten times the iron content that it really has. None the less, all green, leafy vegetables do contain plenty of iron and also high levels of protein. On top of that, they encourage the growth of Lactobacillus in the gut, the beneficial bacteria that some people spend a fortune ingesting in ‘probiotic’ yoghurts and such.
I quite enjoy a dollop of ‘green’ as a side dish in any meal, but there are lots of other ways to use it, such as spanakopita, lasagna or spinach, feta and dill filo triangles. It seems to have a bit of an affinity with chickpeas, as in many Mediterranean recipes.
Many of the above species are natural shade plants, but even those which aren’t can benefit from some shade. Leaf beet naturally grows in the open, but shade leads it to produce larger, more tender leaves, so I layer it under the apple tree. It isn’t a perennial but self seeds so reliably that it doesn’t really matter.
Cuteness overload in the allotment today. The baby wrens have just fledged and are bombing about the place like tiny balls of fluff, each with a tiny stub of a tail sticking bolt upright at the back in the way that wrens have. They are unfortunately far too small and fast for me to get a photo of, but it set me thinking of some of the other wildlife that has been seen in the forest garden over the years.
Birds easily top the vertebrate list, such as the robin that follows me around hoping for worms* or the crowds of starlings that hang out in a nearby cypress, swooping down in a continuous feed to take a turn bathing in the pond. They flit down lightly, splash around madly creating a mini fountain in the pond and then flap back up labouriously on wet wings. Sometimes however, all the birds fall silent and scurry for cover. That is when you look around for the sparrowhawk. One time when I was working in the garden I heard what can only be described as a feathery thump behind me and looked around just in time to see the hawk heading off with a small bird in its claws.
(*Supposedly robins first developed the habit of following large mammals about due to pigs, which dig up large numbers of worms and grubs as they rootle around. To them, a gardener is just a pig standing up.)
Mammals are usually harder to see. We had a young fox coming into the allotments earlier in the year. Andy, our local photographer, eventually got a picture of it but it had us guessing for weeks. One of the most noticeable signs of its presence was the fact that it really loved digging up my woodchip paths, presumably looking for grubs underneath to eat. It also left tooth marks on the floor of the beehive. Other mammals are more obvious, such as the young hedgehog that I found ambling down the path one day.
I pile twigs and branches up in a ‘habitat pile’ for hedgehogs to hibernate in, so it’s possible that this one came from there. Other mammals that can be seen in the allotment include the occasional squirrel and bats flitting overhead at night. While a lot of the wildlife is obviously coming in from the surroundings, it is very noticeable that the forest garden always has a lot more bird and insect life than the surrounding allotments. Wildlife seems to be another of the things that come for free with a forest garden.
Not all the plants in the forest garden are there to feed me. Some are there to feed the garden itself.
The main two types of plant I have planted for this purpose are the nitrogen fixers and the dynamic accumulators. There’s a third kind too, but if it’s there it wasn’t put there by me.
Nitrogen fixers are the simplest. They are plants that, unlike most, can pull nitrogen, the main component of fertiliser, directly out of the air rather than needing it supplied as soluble nitrates by other organisms, such as gardeners. To be completely accurate, they don’t do it themselves either, but co-operate with bacteria in their roots which do the job for them. Most of these plants are legumes, in the pea and bean family. Worldwide, legumes come in all shapes and sizes, from tiny herbs to mighty trees. Native British legumes are a bit deficient at the mighty-tree end of the scale, but we have a wealth of smaller ones.
The largest legume you’ll usually see in Scotland is Laburnum, better known as a bright yellow street tree than as a nitrogen-fixing powerhouse. I haven’t got one in my own forest garden but Graham Bell has several in his rather larger one, feeding the rest of the system through a steady stream of cuttings. The only leguminous tree I have myself is a Siberian pea tree (Caragana arborescens), which is a relatively new addition that is yet to seed. When it does, I am fascinated by the idea of seed described as being very similar to lentils growing on a tree.
Down at shrub level, legumes are an essential component of the Scottish landscape: the furze and whins that turn whole hillsides a mad yellow and fill the air with intoxicating coconut-vanilla scent. In the forest garden, I draw the line at gorse (Ulex europaea) due to its extreme spikiness, but make a place for broom (Cytisus scoparius).
In the herbaceous range, the familiar peas and beans give a yield at the same time as fixing nitrogen. This year, I’m also trying a variety of white lupin (Lupinus albus). The drawback is that none of them are shade tolerant so they cannot be stacked in with other species. This niche is taken by various other, mostly smaller members of the family. I have an assortment, including an everlasting sweet pea (Lathyrus latifolius) growing in about my raspberries. It provides occasional pea shoots for a stir fry as well as fixing nitrogen. In the ground layer under the fruit trees I have wood vetch (Vicia sylvatica), which is there purely as a nitrogen fixer.
Dynamic accumulators don’t have any supernatural nutrient-fixing powers, but move nutrients around in ways extremely useful to the gardener. The king of them all is undoubtedly Russian comfrey (Symphytum x uplandicum), which is also widely used by organic gardeners to provide organic feeds. The beauty of comfrey is that it is extremely deep-rooting. Not only does this mean that it can safely be planted under fruit trees without competing too much with their roots, but it allows comfrey to scavenge nutrients, especially potassium, from deep in the soil where they would otherwise slowly be leached out and lost to the system. This really illustrates the beauty of forest gardening for me: the way the system really fills the available space.
The third kind of organism that feeds the forest garden is not a plant at all but a class of fungi called mycorrhizae. Mycorrhizae have a symbiosis with tree roots, exchanging nutrients like nitrogen for sugars made by the tree. In a typical forest, one tree will have several species of mycorrhizae and each fungus will have several client trees, meaning that the entire ecosystem is interlinked in a global trading network. Fungi are the dark matter of ecosystems – they influence everything but it is very difficult to detect them – so it is unknown whether or how quickly a mycorrhizal net gets established in a forest garden, but is a real possibility that a mature forest garden has this invisible trading web moving nutrients around to where they are needed most.