It’s compost week this week (13th to 19th March), and we are aiming to raise awareness of the benefits of home composting. We have been chatting lots with the team at the Vale of Glamorgan’s Project Zero, where they are working on the Council’s response to climate emergency and encouraging others to make positive changes. They are keen to highlight the benefits of home composting too.

Did you know, composting at home for 1 year can save global warming gases equivalent to all the carbon dioxide (CO2) your kettle produces annually or your washing machine in 3 months (recyclenow.com).

Why Compost?

Setting yourself up with home composting is a great thing to do, it:

• Saves waste, recycling your own food and other garden waste into useful organic matter, which feeds your garden and builds soil
• Use it to mulch, helps soil retain moisture and nutrients and reduces weed growth
• Attracts beneficial organisms to the soil, no need for pesticides and fertilisers
• Great way for children to learn that they can make a difference and have a positive effect on the environment and learn about the cycle of life
• No need to depend on external sources for compost, saves money

Making compost

Types of compost for a home garden:
Hot composting – you need a large heap, which you turn often and it gets hot, so creates compost quickly
Cold composting – the most common form, add food and garden waste to dalek plastic bin, or wooden box heap, often made out of pallets. A slow process, taking a year or so to get useable compost
Bokashi – good for under your kitchen sink, uses fermentation to breakdown all food waste, which then needs to be composted down further before using on the garden
Wormery – another space saving way to compost your food waste, produces added bonus of worm tea

Here we uncover some tips for cold composting at home with a dalek bin or wooden box piles.

Once you have decided what type of compost you are going to make and what container you will use, you need to think about where to site it. A cold compost heap in sun will compost more quickly and it will dry out more quickly, so you’ll need to monitor the moisture, but don’t take up prime growing space with your heap. A shady spot will be just fine, just a little slower if you are cold composting. Aim to have your wooden box or dalek bin on the soil, so the worms and other beneficial wildlife can get in.

You may need to go to some efforts to protect your heap from mice and rats, putting a wire base which overlaps the edges and the ground. You may find your warm heap attracts slow worms, this is excellent in lots of ways, but if you do find them, you won’t want to disturb them, so you will have to wait for them to leave before using your compost. If you get a lot of ants in your compost, it’s usually an indicator that it’s too dry, so water it. It should feel like a damp sponge, not too wet, not too dry either. Slugs in compost are your friends, especially the big leopard slugs, they eat the little black slugs that eat your lettuce.

Compost is a process that depends on circulation of air (aerobic), so add some twigs and sticks to the base of your compost. If you are adding grass clippings, make the layers thin so it doesn’t turn into sticky sludge. Grass clipping are excellent activators, they raise the temperature so quicken the process. It’s better to layer your green and brown materials if you can, like making lasagne, for example by adding food waste from the kitchen in a layer around 10cm deep, then add a layer of cardboard.

The more you turn your heap, the quicker it will produce rich earthy compost for you. But if you don’t turn it at all it will still work, it will just take longer, and you need to be more precise with layering your greens and brown to make a good end result. If you have two or three wooden boxes, it’s easy to move from one to the other. With a dalek, it can be a bit messy, but just remove the dalek, fork the compost onto a tarp or flat cardboard, replace the dalek and fork it all back in.

Some people are uncertain about using cardboard because of the glues used in its manufacture. It’s such an available source of browns from the waste stream….you’ll have to make up your own mind, and it will depend on what other browns you have. If you have the funds to buy in browns, choose miscanthus grass rather than straw. It’s hard to find straw that’s been grown without pesticides or other chemicals. Some people swear by adding guinea pig and other animal bedding to there heaps.

You can go around collecting compost materials from your neighbours green bags, but it’s better to talk to them first as you don’t know what the materials might have been sprayed with. Good to get into conversation with your neighbours about why using pesticides and artificial fertilisers is harmful too, you may be able to share some tips with them to help them move to more climate and wildlife friendly gardening practices.

Your compost should not smell, if it does it’s likely it has started to ferment – not enough air means it will turn anaerobic (it’ll smell gross like rotting), and that’s not what you want. If this happens, spread the compost out on a tarp to dry and add it back into the heap with lots of brown materials. You may get flies in your compost, they are eating the rotting fruit and veg, they are harmless, but if there’s a lot you can reduce the numbers by covering exposed fruit and veg with browns.

If you’d like to learn more about composting, this book is an excellent guide.

Here’s a usual visual reference to show you what, and what not to add to your compost. Do make sure that your teabags are plastic free!

Using your compost

Depending on what you have added, sometimes compost can be too acidic, especially if you eat, therefore add a lot of citrus fruits to your food waste. If it is, add ground lime or wood ash. See here for common composting problems and how to solve. Test it by potting some up and sowing a runner or broad bean seed in it. If it grows away happily, your compost is good to go.

You can also do this test with any manure you have managed to source from local stables, to be sure it is free from aminopyralid. If you are collecting manure, it’s worth talking with the stable owners about their practices, the antibiotics they give to horses can appear in the manure if it’s not separated out, and it can interfere with the health of the microbes in your soils. Best practice is to seperate the manure that’s produced in the days after the horses have had the antibiotics, so ask!

Once your compost is ready it should smell earthy and pleasant, but not sweet (if it smells sweet it may be lacking in oxygen, add more browns and leave for longer), but it will likely be full of worms! Here’s more info about smelly compost.

The worms are not the kind that live in your garden soil, and you want to aim to keep them to put them back into your new heap. Do this by laying the compost out in small pyramid piles. The worms are drawn to move away to the bottom of the pile to get out of the light. Leave the piles for a little while. You can then remove the top and sieve it. Sieve either using a mesh grill you have made, a sieve you can buy, or one of those mushroom baskets you see stacked up in the greengrocers. Put the larger material and worms back in your heap.

You can add your sieved compost to large bags to mature before use. Or put down on your garden soil or around plants in pots as a mulch. No need to dig it in, do No Dig, the garden worms will do the job of bringing it down into the soil for you, so you can sit back and have a cuppa instead.

If you want to use it as a potting compost, you’ll need to mix it with coir, garden soil, a bit of sand for drainage, and perlite or vermiculite for a lighter structure. You can also use composted woodchips or leaf mould. If you’re keen to do this, have a Google and see what recipes you can find to suit the materials you have. Leaf mould is easy to make, just gather leaves, add to a wire mesh cylinder or big bag with holes in and leave for a year, it can also be used as an excellent mulch.

Happy Composting!