Discovery
The Challenge of Traditional Composting
I’ve been composting for years, using the resulting compost on my vegetable beds and around my fruit trees. Over time, my soil, once hard clay that baked in the summer sun, has become more structured and friable, teeming with worms and other beneficial creatures. The soil is now much easier to work. Despite these improvements, my crops were often disappointing. Even with the addition of rotted manure, "greedy feeders" like cauliflowers and Brussels sprouts struggled to thrive.
The Humanure Experiment
For the last ten years at least, I’ve been supplementing my compost with humanure – a mix of our toilet waste and sawdust (see the humanure guide for details). While this added some fertility, my crops still weren’t prize-winning, and the effort seemed disproportionate to the results.
The Nutrient Loss Problem
I’d planted a walnut tree downhill from my compost heaps, hoping it would benefit from any nutrients that leached into the soil from my compost. The tree grew like a weed. One day, as I was standing at the top of the garden looking down the hill, I was astonished to see the top third of the walnut tree snap off, move slightly to one side, and fall to the ground. It was not a windy day – there was barely a breeze!
I’ve since learned that it’s easy to over-feed a tree. If you do, it will grow rapidly, but the wood it produces is weak and sappy. It is prone to producing too much sap, which makes it a target for greenfly, scale, and other pests. The wood is soft and weak, and as I saw with my own eyes, very prone to breaking.
That gave me a clue as to how much nutrient was lost from the bottom of my compost heaps.
Commercial Compost
Commercial composts often include tiny blue or green plastic balls. These aren’t contaminants; they’re deliberately added slow-release fertilisers encased in plastic. While effective, these plastic particles remain in the soil long after the compost has broken down.
Is it possible to make homemade compost that’s as fertile as these commercially fortified options, without the plastic? Absolutely – and with even greater fertility if desired.
Solving my Rat Problem Solved Everything Else
One persistent issue was the rats that found a home in my compost heaps. No matter how many I trapped or how vigilant the local cats were, the heaps provided them with food, warmth, and shelter. Whether I added cooked scraps or only raw materials, the rats thrived.
The solution to the rat problem led me to solve my fertility issues as well.
I built compost bins on a concrete base with masonry walls. This kept out the rats and allowed for better control of the composting process. I put a plastic pallet in each bin and covered it with stainless steel mesh. This was initially to allow drainage so that the heap couldn't become waterlogged. But I realized this also allowed me to ventilate under the heap, allowing plenty of air to pass through. I used an airbrick in the bottom row of bricks to allow the airflow. Then, of course, the bins needed draining, so I made the concrete beds have a slight slope and installed a pipe to collect the liquid that drains from the heap.
The Result
Zero rats. And this system produces rich, evenly decayed compost without the need for turning. The liquid that drains from the heap is an amber-coloured fertiliser far superior to the usual 'nettle tea.' With two bins in rotation, I always have a supply of 'black gold' compost and nutritious liquid feed, providing all the fertility my garden needs.
The Liquid - Almost Magic!
Even though I suspected a lot of fertility was being lost into the ground, I wasn't prepared for how useful the liquid turned out to be.
I experimented with diluting it and feeding a few plants. I was careful to note which plants I'd fed and which I hadn't. I was hoping to see a difference within a few weeks. However, the morning after I'd fed the plants, I couldn't believe my eyes! Tomato plants were thicker in the stem, with a darker green leaf colour, and were pushing out new shoots. Wherever I'd used the liquid, there were already signs of deeper colouring, new shoots, and leaves.
But I was delighted when I tried the liquid on some young trees in my forest garden. I'd planted peaches, nectarines, and apricots that I'd grown from seed. The trees that weren't damaged by voles, deer, frost, or drought were slow growing, and I was losing hope I'd ever get any fruit for my efforts. But these were the trees that responded most powerfully to the liquid feed. Like the tomatoes, I saw immediate results – well, overnight anyway. But they just didn't stop growing. I fed them every 10-14 days, and they grew like crazy. In 12 weeks, trees that were just two feet high (though 3-4 years old) grew to six feet high!
Look - my first nectarines. The tree had grown from only 2 feet high to 6 feet high that summer! And the following Spring...
And here, my first apricot on a tree grown from seed (in my greenhouse) which had grown only slowly and produced nothing before.
And here too, also in my greenhouse, my first pomegranates were that year.
And this tree in my food forest attempt, growing out from its protective cage, is a stone pine – the kind of pine that eventually produces pine nuts. Again, from two feet high to this, over 4 feet high, in 12 weeks.
But look again at the photo of the apricot. See the leaves are black in places? That's sooty mould. It's unsightly but doesn’t harm the tree. It's just mould that feeds on the liquid that comes from the leaves. Here, the liquid is too rich in sugar, and so the mould thrives. The tree is growing too fast. You can't see it in the photo, but there are also scale insects on the branches, also feeding off the too-rich sap.
I’ve learned since my early experiments that commercial apricot growers feed their trees enough to make them grow 2 feet a year. That's enough. They'll be healthy like that. Their wood won't grow weak and sappy, they won't be too prone to insect attack and mould.
But now I know what it takes to make these trees and vegetables grow. And I'm learning how much liquid to use. Trees I feed little by little throughout spring and early summer, making them grow well but not too much. Then I leave them alone during late summer and autumn so that the growth slows down and the wood hardens. Vegetables I feed more intensively, especially cabbages, cauliflowers, squashes, and tomatoes, and I feed them until late summer.
All I was doing was trying to solve the rat problem but clearly, I've found out why my compost wasn't providing enough nutrients for my plants, and I have the solution at my finger tips.
