Compost composition

compost corner

Compost corner

Today, in between the rain showers, I dug out some compost to add to the flower beds. I found quite a decent amount of composted material at the bottom of the bin, but to be honest it is more slimy than crumbly.

I’ve done some research, and discovered I’m being too green!

‘Greens’ and ‘browns’

Ideally, compost should be a 50:50 balance between green and brown materials. The ‘greens’ are quick to rot and provide nitrogen and moisture, while the ‘browns’, which are slower to rot, provide carbon and fibre, and help air pockets to form.

To date, the bulk of my compost has comprised fruit and vegetable peelings/skins, used tea bags and grass mowings, so I need to change the balance a little. Of the ‘brown’ items in the lists below, I compost egg shells, used kitchen towels and a few leaves. From now on I’ll be adding egg boxes and other cardboard along with the contents of my vacuum cleaner (ew!), and next time my husband gets his hair clippers out, well …

Greens

  • Animal manure with straw
  • Coffee grounds
  • Comfrey leaves
  • Cut flowers
  • Fruit peel, cores and pulp
  • Grass mowings and hay
  • Old bedding and vegetable plants
  • Raw vegetable peelings/waste
  • Soft prunings, hedge clippings and plant debris
  • Tea leaves and bags
  • Urine
  • Weeds (see text)

Browns

  • Autumn leaves
  • Cotton wool and wool
  • Egg shells
  • Egg boxes and plain cardboard
  • Evergreen prunings
  • Hair
  • Natural corks
  • Paper bags
  • Straw
  • Sweetcorn cobs
  • Used kitchen paper
  • Vacuum cleaner contents
  • Wood ash

Composting weeds

I spend so much time pulling weeds out of the garden that the last thing I want to do is reintroduce weed seeds back into the soil. So it has been a bit of a revelation to find out that it’s okay to compost weeds, provided you follow a few simple rules. Before composting, make sure annual weeds:

  • haven’t yet reached the seed-bearing stage – so to be extra sure, I plan to add them to the compost before they have flowered
  • are not the type that propagate by runners.

Perennial weeds are a bit trickier. The roots of ground elder, couch grass, nettles, creeping buttercup, dandelion and docks can survive for a long, long time and will keep growing in the compost. If you’ve got the space then you should keep them in darkness for 2 years before adding to the compost, but for most of us it’s probably better to play it safe and only add the leaves of these plants –  not the roots!

You can make extra sure that you don’t spread weeds in your garden by practising ‘hot composting’, i.e. turning the pile regularly and ensuring it really heats up. One website that I visited suggested using a compost thermometer: a hot compost pile of 60–65 degrees C (140–150F) for several days, or 49 degrees C (120F) for a longer period, will kill any weed seeds. But, to be frank …  life is too short to be checking the temperature of my compost heap!

Failure is not an option

The good news is, you cannot fail with composting, because whatever you do …  it happens. Whatever composition and consistency you end up with, the addition of organic matter to your soil will benefit your plants. Compost improves soil structure and aeration. Importantly, for my garden, it loosens clay soil, and if you have sandier soil, the addition of compost will increase its water-holding capacity.

Ultimately, plants grown in compost-rich soil will be healthier and stronger, and will fruit and flower more. Oh, and you never know, there may be other benefits … it might make me vacuum more often!!

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