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Worms in the Compost Bin
There are 2 stages in the composting process – a hot
fast one and a slow cool one. At the top of the bin, the material
rots down at a high temperature and sinks quickly. Beneath this,
compost that could be used for mulching slowly turns into fine,
crumbly material. It is here that worms play a vital part.
Worms naturally live in the soil and break down plant debris so will
be attracted to a compost bin where there is a lot of plant debris.
When a bin sits on the soil, it will quickly fill with worms. You do
not need to add any more worms.
You may find them round the lid of the bin where there is a lot of
condensation and it is moist, but this also suggests the compost at
the top isn’t very hot and it may be too dry, so you’ll probably
want to do something about that. See
How to Compost for more information.
Special Worm Composting.
Worms will turn peelings and kitchen waste into
deluxe compost, so rich it is more of a
fertiliser and invaluable for container grown plants.
Here's how to convert your kitchen scraps into this best of
composts.
The Worms we use:
There are at least 25 different species of earth worms in Scotland.
They break down decaying vegetation like leaves and plant debris and
this adds valuable nutrients to the soil. Many will provide good
drainage by burrowing down 20-25cm into the soil and a few go even
deeper. Some species live mainly on the surface in leaf litter and
decaying vegetation and it is these that we use in our wormeries.
These are also the species you are most likely to find in your
Compostabin, it is an ideal habitat for them.
The species most commonly used for a wormery are
Eisenia foetida (the brandling or tiger worm),
recognisable by its red stripe, and the larger
Dendrobaena venata (the European night crawler).
A Worm's Life
Breeding
Worms are hermaphrodite, having both male and female
reproductive organs. Each worm produces egg capsules, but must first
be fertilised by contact with another worm. Each healthy worm, under
favourable conditions, will produce an egg capsule every 7 to 10
days. Between 2 and 24, usually 4, baby worms will hatch out in 2 or
3 weeks. The new worms will reach breeding age in 2 or 3 months. The
compost worm will then reach its full size after another 3 or 4
months.
Ideal Living Conditions
Worms
need a damp, but not soggy, environment. They thrive in cool
conditions: the optimum temperature is 15°C, though some species,
notably Dendrobaena, can survive in temperatures ranging
from 3°C to 27°C. However, survival is not the same as being content
- worms become dormant at the extremes of their temperature range
and stop feeding. So to keep them eating lots of your compostibles
you need to give them their preferred temperature range - 10°C to
20°C - so site your wormery in a shady place and protect it from
winter frosts.
A thick layer of damp newspaper helps to insulate them from
temperature swings.
Worms
need a steady supply of fruit and vegetable peelings. They
will eat most types of fruit and vegetable waste, but not orange,
lemon or grapefruit skins (these are too acid) and they dislike
onion skins and leek leaves. They are particularly fond of banana
skins and melon rind.
Worms feed on decomposing material, so do not expect them to get
stuck in to the fresh stuff you put in. Having no teeth, gums or
tongue!, they have to suck tiny scraps from the soft edges of their
food. If you cut up the material you put in there will be more edges
to soften more quickly which will allow the worms to start eating
sooner.
Worms like to eat newspaper and cardboard (the glue between the
layers of cardboard is good protein for them), so the thick layer of
damp paper or card that goes on top of their food will be eaten away
and will need replacing.
To aid their digestion worms need egg shells.
Worms break up the food they eat in their gizzard, just like
a hen, so require tiny bits of grit to act as grinding stones.
Adding crushed egg shells to their food provides them with grit and
the calcium in the egg shells help to prevent their environment
becoming too acidic.
Worms need air so make sure the bin
isn't waterlogged. Worms can drown.
the wormery
There are several types of wormery available,
usually costing around £65+. You can also make your own wormery very
cheaply. Choose a shady part of the garden, make a square wooden
box, 45cm x 45cm x 60cm tall. Staple a permeable membrane to the
bottom of the box to allow excess liquid to drain out and stop moles
burrowing in. Make a solid, well-fitting lid for insulation and to
stop your worms being soaked by the rain or eaten by blackbirds.
For
a commercial or home-made bin, worms will need bedding. Place a
layer of damp leafmould, 5cm deep, or soak a coir brick and use it
as their base. Place approximately 1kg of works on the leafmould or
coir and scatter a thin layer of food on top. Place a thick layer of
damp newspaper over the food and leave the worms to it.
After about a week add a small bucket of chopped up kitchen scraps.
As the worm population increases, you can add more scraps. Make sure
there's always a good thick layer of damp paper to keep your wormery
moist and cool. You'll need to keep adding more paper as the worms
consume it.
There is usually a sump at the bottom of commercial wormeries to
collect liquid. Be sure to drain this off from time to time. You can
dilute this 1 part liquid to 5 parts water and use it as a feed for
container grown plants, or simply pour it on a compost heap.
Harvesting the wormcast
After a year there should be a good thick layer of
worm-made compost at the bottom. On a sunny spring day, plce a sheet
of cardboard close to the bin and, using gloves, scoop out the top
layer of semi-decomposed material and put it on the card. Then pile
up the finished compost from the bottom of the wormery on another
sheet of cardboard. The worms will escape from the light so, after
about 10 minutes, you can skim off the top layer of compost knowing
there will be no worms in it. Repeat this process till you've
separated most of the compost from its inhabitants.
Leave your worms a 2-3cm layer of finished compost for their "bed",
put the worms back on top of this and cover them with their food and
an extra thick layer of damp newspaper or soaked cardboard.
USING THE WORMCAST
A wonderful addition to potting mixes. See
DIY Potting Mixes. As
wormcast is much stronger than general compost, use half the
quantity recommended in the recipes covered in that page. An added
advantage is that wormcast contains no weed seeds.
Wormast can be used as a mulch but this material is very precious so
target it with care. Container grown plants often need a pick-me-up
in early to mid-summer, so sprinkle some wormcast on the surface of
the pot and watch your plants respond.
Tomatoes are particularly appreciative of wormcast.
Any problems with your wormery Contact us
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