Hole composting

Short version: Collect fruit and vegetable peelings and cut offs, tea leaves and coffee grounds to bury in a hole in the garden. Sound ridiculous but I swear this is a real thing.

What to compost?

For hole composting you’re best sticking to green waste from the kitchen: Vegetable and fruit peelings, cut offs and cores, tea leaves (bags are fine – but be aware that the bag itself will often contain plastics – see ‘Composting teabags’) and coffee grounds. You can add a small amount of brown waste like shredded cardboard. For more details on composting see ‘Why and what to compost’. I don’t include garden waste as you get tend to get larger quantities of one type of thing, meaning you have to dig a pretty big hole and you won’t get a large variety of nutrients.

How to hole compost?

I have an old plastic sweet tub that I keep next to the sink that I just sling stuff in. Something with a lid keeps smells in and flies out (mostly fruit flies as house flies are attracted to meat). Every few weeks I’ll give it a good wash (in the dishwasher usually – cause I’m lazy) just to keep the smells and mould at bay. I don’t use composting bags (bags that go into compost that break down) as they require energy to process the materials, to make and to deliver… and they’re not free. Also the smell in my tub isn’t bad as it’s all vegetable and fruit matter and stays on the counter top a maximum of a week. I do use composting bags for the council collected food waste. That smell just makes me want to go shower. If composting bags help you to compost, then better to compost and use a bag than not composting at all.

When it’s full I’ll either bury it in the garden or put it in the compost bin. Despite saying that hole composting is the best, I mention a compost bin because I’m afraid it isn’t always appropriate to use hole composting.

Dig a hole. I just use a trowel. For a large sweet tub, I dig a hole that’s about 40cm wide and about 20cm deep. The deeper you bury, the less likely something will be attracted to it and dig it up. We have cats and foxes around us, and they don’t care for the type of stuff I bury.

Chuck the contents of the tub in. Give it a mix with the soil underneath it (and maybe an extra chop with the trowel) to introduce lots of microorganisms to it.

Cover it with the remaining soil.

Where to hole compost?

My memory isn’t as good as it used to be so when I hole compost, I start at one end of the garden, bury my kitchen waste and then mark the next spot to dig with a trowel.

I move hole by hole round the garden and when I get to the end in about 2 months or so, I’ll go back to where I first started. Things will have had time to turn into lovely compost, especially as the worms and microorganisms in the soil will have helped out. The worms will burrow through the soil and compost and aerate it. The microorganisms need air to do their thing and albeit slowly the worms tunnelling through will help spread out the compost with its nutrients through the soil around it.

If you have any perennial plants growing, then you want to bury away from the roots. By digging you can damage the roots. You also don’t want to put a large amount of uncomposted material too close to a young plant. During the breakdown process the plant that is growing and the microorganisms doing the breaking down compete for resources. Therefore, it can be worse for the plant in the short term.

When to hole compost?

This is something that I prefer to do in the winter months. This is when I have the most access to the soil as many of the plants have died back.

If you grow annuals, then you should wait till all the plants have been harvested and then fill your growing space with lots of buried pockets of potential goodness. Start doing it as soon as you have harvested and carry on till around early February. Then the material has time to break down before planting begins in spring. 

This is why as well as hole composting, I do have a compost bin (see ‘Bin composting‘ for details). I can’t always access the soil to dig a hole, so during this time it goes into a compost bin.

A variation on hole composting

Every now and then I reclaim a bit of the lawn and make another vegetable bed or find myself a pallet that I recycle into a raised bed (see ‘Pallet planter’). I have 2 ways to fill the beds that don’t involve buying compost:

  1. Cover the bed with a couple of sheets of cardboard. Then every time I have a sweet tub full of waste or have garden waste, I lift the edge of the cardboard, chuck the waste in and then let the cardboard fall back down. The cardboard keeps animals from digging in there. Occasionally I shred a cardboard box and add that in and sometimes when I have a spare moment, I’ll give it a mix with a garden fork. Because you’re not digging a hole once a week it’s even lazier and quicker.
  2. When I haven’t had access to the soil in the summer months, I collect the kitchen and garden waste in a compost bin and then just pour all that in, in one go.  

When the bed is as full of compostables as I’d like, I give it all a good mix and cover it with a 5cm layer of old compost. This will usually be the ‘spent’ compost from pots that have had annual fruit and vegetables growing in it and it would be low on nutrients. I then leave it for around 2 months for the worms and other organisms to move up into it out of the soil and for the microorganisms to break it down. The smaller everything is chopped up before it goes in the more it would have decomposed. Bits of wood don’t decompose quickly.

Anyway, hole composting is great when you don’t have the space for a compost bin, or just want an easy way to add nutrients back into the soil.

You can really see the results of the composting. January 2019 I made this pallet planter. The bottom of it had sheets of turf that I had removed from the lawn. That introduced lots of microorganisms and worms. The middle was all garden and kitchen waste, then it was topped with soil from spent pots:

Please please please do give it a go – even if you dig just one hole! It’s better in the garden than landfill or being collected for processing. It’s a free, natural way to fertilise your garden. It’s good for the environment and it’s good for your plants.