Soil is the very soul of a productive garden. Look after it, and everything else will fall into place. And how do you get great soil? Nourish it with the good stuff: garden-made compost!
Ready-to-use compost has a lovely rich, dark colour, and it smells like a forest floor. It might still be a bit lumpy with a few twiggy bits still in there, but don’t worry about that. Adding it to your soil in late autumn means it has all winter to continue breaking down, so that it will be super soft come planting time in spring. But if you want something a bit finer – say, to add to a potting mix – then sifting it through a sieve is super easy to do and would leave a finer, crumblier compost.
At this time of year, digging out your mature compost also frees up your compost bin for the influx of all of autumn’s leaves, weeds, old crops, prunings and whatnot. While the bin is empty this is also a good opportunity to check that it’s still in good shape, and make repairs where needed.
Really effective compost heaps, once they get going, can reach 130ºF or 55ºC or more. A hot heap means the microorganisms responsible for decomposition are doing their thing. To help insulate the heap you can line the walls with sheets of cardboard. This will itself rot down or slip down with time, and that’s fine, but before that happens it will help to get things going, especially at this fresher time of year.
A cubic meter/35 cubic feet/1.3 cubic yards – or more – is an ideal size for your compost. Larger heaps heat up faster and will slow down less during the winter months, because they’re able to hold onto heat for longer. But that doesn’t mean smaller heaps are no good – they’ll just take a bit longer. Many off-the-shelf compost bins are a great solution for smaller gardens, and will keep things looking tidy too.
If you can, set your compost onto soil as this will make it easy for worms and all those essential microorganisms to get to work. But anywhere is fine, and you can jumpstart the process by introducing some composting worms and perhaps a few handfuls of mature compost to get what you need in there quick.
What Can You Compost?
Compost is a beautiful thing because it transforms what might be wasted into stunning, nutritious plant food. It’s magical. And when you get to grips with it – literally – it connects you in a deep and meaningful way to the rich circle of life. It’s just exciting, right?!
There’s a lot of discussion and debate about the best compost recipe. Everyone has an opinion, but it really doesn’t have to be complicated.
For me it’s all about getting a good variety of ingredients into my heap, because a broad range of compostables means a broad range of plant nutrients, which will of course be healthier for what we grow.
There two types of compost ingredients: browns and greens. Browns have a relatively high carbon content. They consist mainly of drier, woodier ingredients. Fallen, autumn leaves are browns – they’ll tend to get really crispy as they dry out over time. Greens are relatively high in nitrogen and tend, therefore, to be fresher, greener, wetter ingredients.
My Perfect Compost Recipe
I like to add a cushion of leaves and then some greens like spent crops, chopped up to make them decompose faster. Then I sprinkle on a few handfuls of wood ash. It’s not essential, but it’s a great way to dispose of the ash from my woodburning stove and make the most of the nutrients it contains. If you use this, just make sure it is genuinely wood ash and not coal ash, or ash contaminated with impurities like bits of metal or burnt plastic – none of which you want in your soil.
Next I add some old straw and torn up cardboard, and some woodier bits from the top of the old heap that need to continue decomposing. These are all browns.
I alternate this with a layer of greens such including kitchen scraps, some weeds and grass clippings. I also add coffee grounds blagged from a local café. It’s worth asking cafés and restaurants for their spent grounds. It may save them from having to pay to dispose of them, and this beautiful stuff is incredibly high in nitrogen, which can really help to fire up your heap. Despite it’s color, for the purposes of composting, it’s a green.
Other compost accelerants or boosters include pet bedding and poo from herbivorous pets like hamsters, livestock manures, and even your own wee, though only if you’re not on any medication.
What you add will depend on what you have on hand in your garden. Get a good mix of ingredients and aim to balance out your browns and greens. As a rule, you’re aiming for anywhere between one-half to two-thirds browns, to one-half to one-third greens. Sourcing enough browns during the growing season can be tricky, so it’s worth keeping some behind for this reason.
What Not to Compost
Anything organic – that once lived – will eventually rot down, but in a domestic composting setup there are a few things you want to avoid. These include any animal-derived products, including meat, bones, milk, cheese and so on, as well as cooked food. These could all attract rats and other vermin. Bread, pasta and grains are best avoided too.
Most weeds can go into the heap, with a few exceptions. First, don’t add annual weeds that have produced seeds because unless your heap gets really hot these could survive and then spread around your garden wherever you use your compost.
Second, do not add the roots of perennial weeds. Here’s some bindweed for example – the top, green growth can be added, but these white roots may survive the composting process. Similar situation with these nettles here. Instead, dump in the roots into a lidded bucket of water and just leave them to drown and rot to a sludge over time. This can then be tipped onto the heap or around your plants to give a little boost of nutrients.
How to Speed Up Your Compost
Getting a good mix of browns and greens should help to speed the composting process up. Ensure the compost doesn’t get too wet or dry. If it feels a bit dry – and this may be an issue during the heat of summer – just give it all a good water, perhaps watering as you add each layer of new ingredients. If it’s quite wet – a bit gooey or sopping wet when you pick it up and give it a squeeze – try adding some more browns and mix them in.
As we head into winter things in my climate can get really wet, so I cover my heap with an old tarpaulin. As a rule it’s worth covering your heap when it’s reliably wet and cool, then uncovering it for the summer months when it tends to be drier.
Another way to hurry things along is to dig out and mix your compost at least once during the whole process. I reckon the best time to do this is once your heap is full. Either dig it all out and then restack, or turn the heap from one composting bay into another, empty bay. In this way you’ll introduce plenty of fresh oxygen right into the heart of your heap, giving it a new lease of life and re-firing the whole process again.
Mixing like this creates a finer grade of compost faster. And it’s a great workout let me tell you, but the end result is quicker compost, which is worth the effort!