Forgot to make leaf mould? You may already have a supply in your own garden. Photograph: Kim Stoddart
Thanks to my local seed swap, bartering pals and my fellow seed-saving editor, Jane; I now have a fine bounty of “plantables” ready and raring to grow for the gardening season ahead. The question is – what am I going to plant them into this year? I assumed mainly garden compost, but I was wrong, and everywhere you look for advice on this subject there’s a different recipe on offer. To make matters worse; most recommend ingredients such as biochar, coir, vermiculite or sharp sand; all of which need to be bought in and are therefore no good for me.
Leaf mould doesn’t cost anything to produce and is supposed to be a key ingredient, but I’ve forgotten to get round to producing any. Oh dear. I really should have seen this coming- I knew leaf mould was important. Annoyed with myself, I start to panic. A decent propagation compost is after all essential:without it, nothing will grow.
Then I think back to whenever I’ve planted seeds directly into the soil before – they have generally always taken. The biggest risk has been whether they’ll get munched by slugs, not that they won’t germinate in the first place. Putting aside all the elaborate, conflicting and frankly confusing recipes for potting mixes that have made my head whirl; I realise I need to understand better what I’m dealing with in order to make it work for me. I happen to know that Ben Raskin, the head of horticulture at the Soil Association has just written a children’s book on compost which seems like a good starting point and just about the appropriate level for me on this subject. I decide to tap him for some ideas.
The issue with seeds, he explains, is that they don’t want too much in the way of nutrients, and bog standard garden compost (on its own) is far too rich for them. You also need the right texture and drainage for seedlings to germinate and grow, which is why ingredients such as coir, leaf mould and vermiculite are recommended in place of peat. Ben suggests wood chippings as another option, which a friendly local tree surgeon can often provide for free. But to use these they have to be well rotted (for at least 12 months) first, so that’s out for this year at least. On the plus side I do have a few molehills around the soft fruit bushes at the back of the garden. Ben points out the fine crumbly nature of the worked soil lends itself well to potting – so that’s something.
A few days later and between rain showers I inspect the moles’ handiwork – it seems they have been rather busy. As I’m walking back with a few buckets of this fine compost ingredient, I spot a bed of hellebores bursting with flower heads. They live in a shady spot surrounded by trees and, it occurs to me, amid a blanket of leaves. Not being a fastidiously tidy gardener, I happen to know that there must be at least four years of rotted down leaves here.
Bingo. It would seem I have lazy gardener’s leaf mould in rather plentiful supply.
Reading into the subject some more, I think the success of home-made seed compost depends on the quality of the ingredients you have to work with. Good compost, while too potent on its own, makes an important addition, as does some of the best topsoil from your garden – and everyone seems to agree that leaf mould provides an essential part of the mix.
I know there’s the issue of germinating weeds, but I’m loath at this point to start pasteurising soil by heating it in the oven. I ask you. I know what the plants I’m trying to grow look like, so it’ll be easy to pick any invaders out by hand.
Based on my positive experiences previously of planting seeds directly into the ground and seeing them flourish, I decide to keep my first batch of seed compost simple. I’ll use an equal(ish) mixture of soil (molehill and top), compost and leaf mould. I think this should do the job. Maybe it pays to be a bit lazy sometimes after all.
Have you tried making your own seed compost in the past, and if so, what combination worked best for you? As always I’d love to hear your experiences and ideas on this subject.