GIY: How to Make Compost

Have you attempted to make compost before or wondered where to start?  In this article Michael Kelly from GIY Ireland explains how to make compost:

The other evening I was going through some notes from a course on soil fertility I attended a few years back with Jim Cronin on his smallholding in Bridgetown, Co Clare.  Jim is a rare breed – a wise sage who wears his considerable wisdom lightly.   The two greatest materials for returning fertility to soil, he says, are seaweed and homemade compost.

Both rank a “10” on his scale of fertility. Farmyard manure composted for one year ranks an “8” while fresh manure (oddly) only ranks a “7”. On the other hand a very old farmyard manure heap with nettles growing on it only ranks about a “1”, because all the nutrients have leached away.

So how to make compost properly?

#1. Treat your Heap with Respect

Treat your heap not as place where you can happily dump all manner of stuff from the kitchen and garden, but with love and respect! It’s like making a loaf of bread – make sure you have the right mix of ingredients. With compost you have to have a 50/50 mix of green and brown material and you have to build up the layers carefully.

The brown layer can consist of straw, hay, wood ash, cardboard, twigs, leaf mould, soil or garden “sweepings”. The green layer should contain seaweed, farmyard manure (hens, pigs, ducks, cows etc), grass, hedge clippings and kitchen waste (veg only).

#2. Try an Open Heap

Jim is a fan of completely open heaps – that is, you basically pick a corner of your garden and start a heap on bare soil which you dig roughly before you start (which encourages earth worms to come up through the heap). There are no “walls” but the basic measurements of it should be about 4ft wide and deep. Start with a brown layer such as straw or twigs of at least 10 inches.

#3. Turn the Heap Regularly

Turn your heap over with a fork monthly to aerate it.

#4. Cover Your Heap


Cover it with cardboard or old carpet to keep the worst of the weather off it. Carry on adding alternate layers of 10 inches or so of brown and green. When you get to about 6ft high its time to move on to a new heap and let that one to rot down. How long this takes depends on what’s in it – could be 4-6 months but you will know when it’s ready by the fact that you have a nice crumbly compost with few or no traces of straw in it – in other words that everything has rotted down.

The overall goal is that you are self-sufficient in the material that you need to fertilise your soil – or as Jim puts it – you “close the gate on fertility”. He estimates that you will get approx 20-30 wheelbarrows of compost from each heap you make. That sounds a lot, but each spring you will need a wheelbarrow of compost for each square yard of veggie bed.

Things to Do in the Garden in February

To Do

  • Turn over the soil only if the weather is dry – if the soil sticks to your boots it’s too early for digging!  Keep off the soil to prevent soil compaction – use timber planks to stand on for access.
  • If you have not already done so order/buy your seeds, spuds and onion sets.
  • “Chit” or sprout seed potatoes – put them in a container (e.g. used egg carton or empty seed tray) and leave them in a bright warm place.
  • Check the pH of your soil – you can buy a soil pH testing kit in any garden centre.  Lime your soil now if required (to reduce acidity in very acid soils), particularly important in your brassica bed.


Finally, we can sow some seeds.

  • On a sunny windowsill indoors, in a heated greenhouse or on a heating mat: sow celery, globe artichokes, celeriac, leeks, onions, lettuce, tomatoes, peas, aubergines, peppers/chilli-peppers.
  • In polytunnel or greenhouse: beetroot, Brussels sprouts, summer and autumn cabbage, carrots, leeks, lettuce, radish.
  • Outside: Weather permitting you can try planting out broadbeans, spinach, kohlrabi, onion and shallot sets, Jerusalem artichokes, parsnip and early pea varieties.


Winter cabbage and cauliflowers, Brussels sprouts, spinach, kale and leeks.

Tip of the Month – Rejuvenate perpetual spinach

Perpetual spinach plants may be looking a little tired at this time of the year but with the milder weather should also be showing signs of new growth, particularly at the centre of the plant. Cut the larger outer leaves with a sharp knife at the bottom of the stem so that the plant can concentrate on this new growth.

Michael Kelly is a freelance journalist, author and founder of GIY Ireland.

GIY aims to create a healthier and more sustainable world by inspiring and empowering people to grow their own food. There are 100 GIY groups around Ireland and 12,000 GIYers involved.  For more tips, information and support visit

Have you made compost before?  How did you get on?  Tell us in the comments below.

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