As the era of peat-based garden compost draws to a close should we perhaps look more widely at the whole issue of compost?
On the face of it, compost is an innocuous material that we all take for granted and many of us who ‘grow our own’ no doubt get through a fair few bags of it every year. It symbolises something wholesome and embraces the hands in the soil element of gardening. Yet for decades we have denuded and eaten up a precious natural habitat, that of peatlands, in order to propagate and grow our own plants. Now at long last that is about to change and the ban on bagged peat-based composts begins in 2024.
Peat based or not, compost has a level of embodied energy; it is in polythene sacks, gets delivered on large fossil-fuel-powered lorries and has travelled significant distances to get to the garden centre and ultimately to our plots. So could we reduce our use of it full stop? Or at least significantly reduce our consumption?
Peat use is bad, it’s far more valuable locking up carbon and forming a wonderful, rich and diverse habitat. Its phasing out has been on the horizon for a while so manufacturers have been working on peat substitutes. Compost, according to the dictionary, is decayed organic material used as a fertiliser for growing plants. So among the peat substitutes are coconut fibre known as coir, bark, wood fibre, bracken, sheep’s wool, municipal green waste and anaerobic digestate. A mixed bag of materials from very mixed sources, many of them apparently waste products, so making compost from them would seem an ideal use. Yet some, like coir, come from halfway across the world and as such have a considerable degree of embodied energy in processing and transport, let alone raising questions of whether they should be used in their country of origin, recycling organic matter at source.
Homemade compost seems an easy enough concept and there are countless initiatives, websites and books on how to make and use it. The end product has a range of uses from potting up plants to mulching and feeding the soil. The issue with homemade compost has always been that it isn’t sterile and often contains significant amounts of weed seed. Whilst this is less of a problem on the open plot, when it comes to seed sowing it is problematic. Many of us ‘grow your own’ advocates have made and used compost for decades, but most of us still resort to bought-in bags of sterile compost for our sowings.
If we could make our own seed compost we could save money and reduce our carbon footprints – so is it possible? How do we avoid the weed seed and get a clean substrate?
Seed compost is essentially a medium in which to germinate seeds, and in horticultural terms is deemed low in fertility, so as not to create overly vigorous growth in the young seedlings.
One solution is leaf mould. Leaf mould is ideal as it is mainly broken down cellulose and lower in trace elements than garden compost. Leaves are a plentiful resource every autumn and if gathered up and left to decay will break down into a very friable medium. Many garden books advocate leaving leaves for two years, but I find in our wet Shropshire climate they break down well in just 12 months. If you are able to gather up just leaves then the resulting leaf mould ought to be virtually free of weed seeds.
Whilst many people see the annual leaf fall as a seasonal nuisance that merely creates work, I view it as a bountiful harvest to be gathered in and stored away for future prosperity. I even go up the road and gather sacks of leaves from the pavements, not so much as an act of community good spirit but as a harvest of a really useful and free resource.
A couple of different grades of garden sieve are perfect for refining your rotted leaves. A finer one allows through all the finest material producing a great seed compost; the chunkier pieces can be used as general mulch under trees and shrubs or can go onto the compost heap to break down further. A larger grade sieve creates a slightly coarser grade material, ideal for mixing with homemade compost and for use in potting on or adding to vegetable beds.
The same technique applies to good garden compost. We have four of the standard council type bins and a larger pallet bin, so all waste material from our plot is composted. When digging it out in a dryish state, sieving it removes the chunkier uncomposted material and creates a lovely fine grade of beautifully composted material. It’s not sterile but if your soil is in good health and full of life it follows that your homemade compost should be good and healthy too.
A great additive if making your own compost is mole hills; beautifully tilled, fine soil that if scooped up and added to compost introduces mycorrhizal fungi and trace elements to your mix – again not weed-free but adds these other benefits. With time and experience you will find your own preferred mix, be it garden compost, soil, leaf mould, etc.
One way to clean your compost from weed seeds is to spread it out in a greenhouse or even just fill trays with it and then leave them in light and warmth prior to use. The majority of weed seeds will germinate and can then be removed to create a cleaner substrate into which to sow. You may not get it 100% clean but getting rid of 90% ought to be achievable. On a bed scale, spread your compost, water and then cover with a clear plastic sheet, this will warm the soil and cause mass germination by letting the light through and you can weed, rake or hoe out the germinated weeds – again cleaning the soil (also called false-seeding).
Even if we still resort to buying one or two bags of sterile peat-free compost for certain more precious sowings, by substituting other compost requirements with our homemade material, we are making a contribution environmentally and saving money. I have reduced my annual usage of 8-10 bought bags of compost to maybe one or, at most, two. A combination of leaf mould, quality garden compost and well-rotted farmyard manure now substitutes bought bags of multi-purpose compost.
I use Melcourt organic compost for almost everything. Peat-free and reliable, I am hesitant to try anything else as this has given me great results for a good while now, but I trialled some Rocket-Gro and was very pleased with it too. I also make my own compost and use this to improve the beds rather than for starting plants off. I’m also a great believer in green manures. I occasionally sow overwintering green manures such as field beans as they protect the soil through the cold months and leave it enriched for spring, but most of my green manures are flowering types such as phacelia and buckwheat that also attract a wealth of beneficial insects for pollination and keeping a good ecological balance. https://markdiacono.substack.com
Compost is a key part of gardening organically. Few of us are self-sufficient in it though. That’s OK when you know what to use in what situations, such as seed sowing, propagating, potted plants, creating beds and mulching.
For the last three years I have been running a small agroecological plant nursery where we grow and sell potted plants, as well as compost. We sell Melcourt SylvaGrow® certified organic multipurpose which is good for sowing, propagating and growing on. It is a mix of coir, fine bark, and green compost with fertility for 4-6 weeks.
Dalefoot wool compost range, all Soil Association approved, is made in the Lake District. The wool compost for vegetables and salads, and the compost for tomatoes perform well. The wool, bracken and comfrey are a hat-trick of performance-packed natural ingredients – feeding plants for at least a season, and requiring less watering, as wool cleverly retains moisture. The Double Strength compost is a super strength spot mulch around heavy-feeding plants (e.g. corn, cucumbers). We have used the double strength to ‘recharge’ spent potting compost 50/50 to add fertility and use again. https://earthedup.com
I have always made as much compost as possible to feed my garden. I’ve grown Bocking 14 comfrey to accelerate it, added ‘liquid gold’ diluted 10:1, made leaf mould and grown green manures. In Hampshire I also had unlimited well-rotted horse manure from the neighbouring stables. I was spoilt for choice.
Moving to a woodland in north Devon has reduced my options. I arrived here with overgrown beds and virtually no homemade compost. I quickly used up all I had plus all the cardboard boxes I used to move house to mulch the beds, so I set up Daleks as a composting system (until I get a chance to build some bigger bays from pallets) and got the Hotbin and wormery running. I was still short of soil and nutrition. I used the shells of beech masts to mulch tender plants as I discovered that slugs don’t like the prickly outer cases. I also mulched with last year’s dried ferns and bracken before the bracken began to produce spores.
For propagation, potting on and top dressing raised beds, I am using Carbon Gold seed and all-purpose composts this year. They are both organic, contain biochar that sequesters carbon in the soil and locks up nutrients, but they do contain coir which is an imported coconut waste product so there are some product miles to consider. The seed compost works very well, retaining moisture as well as soil structure. The all-purpose compost produces good plants in pots and works well as a top dressing on no dig beds, although I have found it needs supplementing with nutrients like powdered seaweed, homemade compost and Rock Dust as the year has progressed.
Wade Muggleton is also the author of The Orchard Book, a practical handbook to help you plan, plant and manage your orchard, whatever your garden size or budget. Order your copy HERE.
Also from Wade:
Tiny and abundant backyard kitchen garden – watch HERE
This article originally appeared in Permaculture magazine Autumn, issue 121
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Wade is an apple tree expert, with over 130 fruit trees in his field orchard, and plenty more as small trees in his backyard permaculture plot, Station Road Permaculture.
