Germination and determination

Spring is an anxious time in the seed frame, interspersed with small moments of triumph.

One area where forest gardening is definitely trickier than annual agriculture is in raising plants from seed. Annual crops have been bred not to hang about when it comes to germinating; mostly they just need a little warmth and a little moisture and off they go. The seeds of perennials are often more cautious creatures; they want to be sure that the time is just right before they will consider coming out to play and they may have very exacting requirements that must be met before they do.

Most simply, many seeds need a period of cold (known as ‘stratification’) before they will then respond to heat by germinating. You can see their logic: they want to be sure that they are germinating in spring and not in autumn. Some take it further and need a period of warmth, then cold, then warmth again. Some are even more complicated, virtually guaranteeing that the gardener will panic and leave them in the one place where they will definitely never germinate: in the packet.

I can’t say I’ve ever really, properly got the hang of growing perennial seeds. Mostly I sow them in pots or seed trays in a greenhouse in time for them to experience a winter’s cold, with mixed results. Last year was a bit of a disaster. I spent lots of money on seeds from the Agroforestry Research Trust and put them in poly bags with damp sand in the fridge, as many books will tell you to, for the amount of time specified for each species. In April I took them out and spread the sand on top of compost in seed trays in the greenhouse. Very little grew.

I think the problem may have been the seeds rotting in the sand and possibly drying out in the compost. This year I have taken a different approach, putting them right from the start in a container where they could grow happily, which will seal up and retain moisture and which converts instantly to a seed tray with built in water tray. This miracle of technology is called a margarine tub.

First I drill some holes in the bottom of the tub, to allow water to drain out. I almost fill it with a good peat-free compost (using rubbishy, cheap compost has cost me a lot of seeds in the past I think, as it dries out so easily), sow the seeds and then cover them with vermiculite and/or sand depending on how big they are. Then the lid goes on and they go in the fridge. Ones which need some heat first have the lid put underneath as a water tray and go in a heated propagator or on the window sill. I’m also giving up on the greenhouse in favour of a more gentle spring heat on the windowsills.

So far the results have been promising. Only a few have actually germinated so far, but you would expect that and all the seeds look healthy and vital.

In the past I have found out that record keeping is as big an issue with seeds as the kit that you use. I’m not one of nature’s record-keepers and I’ve already managed to lose track of which of my seed potatoes are earlies and which are maincrop as I mysteriously forgot to note which varieties were which when I set them up for chitting. The useful thing about the margarine tubs is the ease with which you can write on them. I write each a label but also write the name on the tub. When they go in the fridge, each tub gets its release date written on the front in large digits.

Where the stratification requirements of a seed would leave it germinating half way through the summer I am leaving it in the packet for the time being. These are generally the ones which would naturally drop their seeds around August and then experience late summer warmth, winter cold and spring warmth. If they don’t get the autumn warmth they go into quite deep dormancy and this is the state that you get a lot of tree seeds in from seed companies. The simplest thing seems to be just to wait for their natural seed fall time to come round again and put them in their tubs at that point.

Seeds that have sprouted so far with me this year include Japanese and cherry plums, Crataegus succulenta (an edible hawthorn, with a very promising Latin name I think!), Allium sphaerocephalon (round-headed leek), Chaerophyllum bulbosum (turnip-rooted chervil) and Asclepias incarnata (swamp milkweed).

Autumn jobs

I finally got round to a very important job in the forest garden – marking where everything is! So many species die down for the winter that it is impossible to remember where you put everything. In a finished forest garden (if there is such a thing) it might not matter, but winter and early spring are the best time for doing a bit of rearrangement and you don’t want to plant your king’s spear on top of your hostas.

The allotment seems very small compared to all the species that I want to try out, so I’m always trying to work out how to fit more in. I try to resist the temptation to plant everything too close together – it’s a recipe for spending the rest of your life cutting things back.

I generally use bamboo canes (using bamboo from the allotment) to mark plants, with a label attached to the cane rather than the plant. Labels attached to the plant get lost when the plant dies down and I find that labels stuck into the soil have a tendency to wander too.

Another job around this time of year is picking up as many fallen leaves as I can manage and using them to mulch the garden. The Aberdeen wind helpfully blows the leaves into great piles, sometimes right in front of my door, so all I need to do is go and scoop them into bags and take them down to the allotment. Forest garden ground layer plants are generally adapted to growing through a layer of leaves anyway, so I can’t think of a better mulch. It protects the soil over winter, helps to keep the weeds down and then starts to break down and feed the soil in time for spring. A few bags a year are put aside to mature into leaf mould for potting.


I can’t believe I’ve been blogging about forest gardening for two months now and haven’t mentioned the p-word yet. In the unlikely event that you’re interested in forest gardening and haven’t heard of permaculture already, it’s a design system that can be used for designing forest gardens, amongst many other things.

If forest gardening and permaculture go together well, it’s no surprise, as forest gardening was the original inspiration for the whole permaculture system. Its founder, an Australian lecturer called Bill Mollison, had become disillusioned with the mainstream agriculture that he taught and was looking for more sustainable, less dehumanising possibilities. The best example he found was the Indonesian home garden (or forest garden), with its recreation of the natural forest structure using edible, medicinal and otherwise useful plants and animals. The genius of permaculture is that Mollison didn’t just become a forest gardening teacher but generalised the lessons of the forest garden into a set of design principles that capture the ways in which forest gardens mimic natural ecosystems but can be applied far more widely to all sorts of design situations.

The best source in the UK for permaculture information is the Permaculture Association. In Scotland, there is a Yahoo group for Scottish permaculture and there in the north east there is a Google group for ASPeN (Aberdeen & Shire Permaculture Network).

The Permaculture Association now focus on the design principles of Mollison’s student, David Holmgren. Personally, I find these an unhelpful rag-bag, mixing up tips about the design process with principles to be applied to the thing you are designing. If you’re finding out about permaculture, I’d recommend digging around for something that uses Mollison’s original principles, which are a much more coherent set, focusing on the ways in which a permaculture design should draw on the strengths of nature’s own systems.


The summer seems to be running backwards this year. After a scorcher of an April and a pleasant May, June was a bit dull and July is now getting its wellies on. Still, at least one member of the forest garden staff is well pleased with the weather.


A pond is well worth making in almost any garden. Mine is tiny – no more than a metre across – but is still stuffed with frogs. I counted 6 pairs of them during the spawning season and they practically turned the whole pond into one wobbly mass of spawn. A few months later, I constantly have to be careful where I put my feet due to the little penny-sized froglets hopping all over the place. As well as the sheer delight of it, this makes for an unpaid army on full time slug patrol – just as well with all the rain.

The ground all around the pond is shaped to run into it and I have an overflow from the water butt that collects rain off my shed roof that runs down into it too. This means that I hardly ever have to add water, a great improvement on my previous attempt which required regular topping up. If you do have to add mains water to a pond, put it in an open container for a day or more first for the chlorine or other treatment chemicals to come out of it.

Hard graft

grafted fruit trees

I was chuffed to see today that a couple of the fruit tree grafts I did this spring seem to have taken: both of apple (Malus domestica) ‘Red Devil’. I went on a grafting course with Andrew Lear, a.k.a. Appletreeman, in March, but I was beginning to worry that the skills graft hadn’t taken.

As well as the usual reasons for grafting fruit trees yourself (cheaper trees and the ability to propagate varieties that you like), I am interested in the technique for creating ‘own-root’ fruit trees. Own-root trees are ungrafted trees, that is, ones where the fruiting variety has its own roots rather than a rootstock, so you might wonder what grafting has to do with it. The reason is that fruit trees don’t usually root from cuttings, so you do a ‘nurse graft’, a normal graft with the graft union planted below the ground, using the rootstock as a sort of life support system for the scion until it can finally be coaxed into putting out its own roots.

Own-root techniques are based on the work of Hugh Ermen, formerly of the Brogdale Horticultural Experimental Station. Fruit trees are usually put on a rootstock in order to reduce the size of the tree and encourage fruiting by restricting the amount of nutrients available to it. The downside of the technique is that the resulting trees are less vigorous and more disease prone. Hugh developed techniques for propagation and inducing fruiting which allowed grafting to be dispensed with. His work is now being taken forward by Phil Corbett of Cool Temperate Nursery near Nottingham.

I’m interested in the technique myself because I do a lot of planting of fruit trees in public spaces, some of them quite rough. I think that own-root trees would be tougher and better able to stand up to the treatment they can get in these places. In particular, if they are broken off they come back true, whereas a grafted tree grows back from the rootstock. In the allotment I’m going to have to experiment with own-root techniques simply because my favourite fruit tree, a Japanese plum (Prunus salicina) came from the nursery ungrafted. It’s a vigorous, healthy tree, sure enough, but also going to get too big for its spot eventually. Then I will have to try coppicing it and seeing what the result is. In the meantime I have propagated it by layering branches, another own-root technique, and planted it out round the housing estate where I stay.

Stop that plant!

ground elder

One thing you have to consider with planting a forest garden is how the plants you put in are going to spread, either by seed or by roots and runners. No matter how much you like a plant, you are unlikely to want it across your entire site. Strategies that stop your own plants from becoming weeds will also help stop out-and-out weeds like creeping buttercup which can otherwise spread through a perennial setup very quickly.

A lot of forest garden species just quietly sit where you put them, getting a little bigger every year and patiently waiting for you to divide them. These are the swots of the class. At the other end there are plants so unruly that it’s a bad idea to even put them in. Nettle is one of these. No matter how many uses this plant has and how good for wildlife it is, it’s just not getting in my garden again. It spreads by aggressive, persistent runners and seeds itself all over the place. Then, when you try to weed, it attacks you. This is one plant I will stick to foraging [2017 update: this turned out not to be true 🙂 ].

In between, there are plants that will try to spread, but that can be contained with a bit of care. There are various strategies for this. Vigorous spreaders like mint and dittander are best planted in a pot sunk into the soil, or you will quickly have far more of them than you are ever likely to need. It’s also a good idea to divide your plot up into beds using weed barriers. I have a good network of woodchip paths which are there as much as easily hoe-able barriers as for access. Sometimes a row of a particularly vigorous but non-spreading plant, like Russian comfrey, can make an effective barrier. Plants that die down early can leave a hoe-able strip behind them: I have a row of wild garlic that I use this way.

Once you have beds, you can match plants by their spreadability. Put all the well-behaved ones together, then corral the adventurous ones in a well-barriered ‘thug bed’ and let them sort it out between themselves. It’s useful to observe in nature which plants manage to come to an equilibrium with each other: this spring I saw a mixed swathe of nettles, ground elder, wild garlic and lesser celandine – all useful edible plants with marked imperialist tendencies – in the shade of a beech tree.

With this in mind, I have finally allowed Margaret Lear of Plants With Purpose to persuade me to try ground elder (Aegopodium podagraria) in my garden. I like ground elder, at least since I discovered that the way to eat it is to pick the only-just-emerged leaves and fry them in olive oil, but I’ve never wanted it in my garden. Margaret’s variety is variegated, so it should be a little less vigorous – and also easier to hunt down if I ever take against it. [You can find out how I got on with ground elder here.]


Out in the rain taking a few cuttings, I took the opportunity today to scoop up a few snails that were out for a wander. Slugs and snails aren’t a huge problem in the forest garden, certainly compared to the annual patch, but I like to try to keep the numbers down a bit. I don’t usually go out in the rain hunting them: my preferred strategy is ‘I know where you live’. I have ideal homes for snails dotted round the garden: a flat rock or slate resting up against another one with a small gap is perfect. I occasionally make a circuit of these and put the harvest on the bird table, which is set up with a few rocks and a handful of weeds so that it isn’t too uncomfortable for the snails while they wait for the thrushes to come. I don’t honestly know whether the thrushes do come – I’ve never seen it – and perhaps all I do is keep the snails busy for a bit while they climb back down, but it seems to work.

A Buddhist friend once protested that this treatment smacked of ‘extraordinary rendition’, but I had become concerned with the amount of nutrients I was taking out of the allotment by removing bucket-loads of molluscs. This way there is a chance that they get cycled around again within the garden.

It’s also very important to keep up a good population of animals that eat slugs, snails and their eggs in the forest garden, so a pond for frogs, a habitat pile for hedgehogs and rocks and boards about the place for beetles are essential parts of my mollusc-control strategy.

Last year we tried a more full-on approach to the problem and decided that if the allotment was determined to produce snails then it was rude not to try eating them. The biggest and healthiest were selected from the snail homes and fed on leaves for a few days to purge them of any grit or poisonous plants that might have been in their guts. They were dropped into boiling water to kill them as fast as possible: once cooked they were scooped out of the shells and prepared various ways – frittering and in a strong tomato sauce seemed to be the best. It certainly added some useful protein to our almost vegetarian diet, but it was impossible to get around the fact that they tasted rather, well, snaily, so this year the birds are getting them again.

The one time when the slugs and snails can be a pest in the forest garden is when getting new, small plants established and here I thoroughly recommend using slug collars. They really work, even in the rain, they are simple and they last forever.

Fruit thinning

I bit the bullet and started thinning out the apples and Victoria plums today. Fruit trees sometimes set more fruit than they really have the resources to ripen, leading to smaller individual fruit and exhausted trees, so while the fruits are still small it can be a good idea to thin them out a bit, which also gives a chance to remove ones which look diseased or deformed before the tree has invested much in them. The Vicky plum in particular has just been wildly over-ambitious this year, setting enough fruit to break the tree, so I took almost half of them off. I always leave this task a bit late as it just feels wrong to be taking unripe fruit off, but my experience is that it really does help.


Ten years ago, I started experimenting with forest garden techniques in my allotment. It’s been a long process. Along the way I’ve discovered a few things not mentioned in the breezier forest garden books, like that most of the UK research has been done in the South West of England and doesn’t necessarily translate to the North East of Scotland, or that a lot of the species described as ‘edible’ are edible only in the technical sense of ‘you can swallow them and not die (quickly)’, or that many of the species extolled will take years of detective work to track down and acquire.

However, I have finally arrived at something that I’m willing to claim as a forest garden: an edible ecosystem to delight the eye, mouth, stomach and heart. An arrangement of useful plants, each in the ecological niche that it likes best – niches created in many cases by the other plants.

I have also realised that I have managed to extend the art in a few small ways. One is by testing what works well in Aberdeen. The situation these days is much better than when I started reading about forest gardens, when practically all the examples were from Australia, but there is still an ongoing need to develop experience in all parts of the country. This is my point in that dataset.

I also think that my forest garden is unusual in its allotment scale. Most forest gardens I have seen or read about have at least a field to play with. I have had to squeeze things in. I’m jealous of course, but I also think that many more people have an allotment or small garden than have a field, so I hope the experience will be useful to others.

My forest garden isn’t finished yet – I don’t think I’m even half way. But I have been asked to share what I have learned and a blog seems perfectly adapted to recording such a messy, ongoing, experimental, evolving process. So here goes…