Worm farm

Farming worms

Garden Life
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Tips from Sarah the Gardener

The key to a good garden is to keep renewing the nutrients season after season, to replace what has been used by the plants and removed as crops. Ordinarily in a natural environment the produce either falls to the ground uneaten and rots where it lays, returning the nutrients used in its creation to the soil at the foot of the plant. Or some creature will eat it and then return it as manure nearby. Eventually the plant itself dies and it becomes a closed cycle of growing and dying and where the nutrients remain indefinitely.

However, in the human-created environment of the garden we often take more than we give. We harvest the crops, clear away the dead and dying plants to put on the compost pile and rake up the autumn leaves as they can look a little messy and can be a hazard on paths when wet. We like to keep our gardens looking nice and tidy. But this continued taking needs to be redressed to maintain balance within the soil so the garden continues to thrive.

This can be done in many ways – bringing in compost, well-rotted manure and fertilisers from the store and following the directions, applied to the soil will re-enrich it for a new growing season. Or even to make your own compost and there are so many different ways of going about this, there is a method and technique suitable for everyone and their budgets, from a simple pile of garden waste and kitchen scraps in the far corner of the garden, to a more complex process of hot composting with the correct ratio of brown and green materials. There are affordable compost bins made of four sides and a lid or at the other end of the scale there are tumblers and other devices that can speed up the composting process.

Leave it to the experts

Or you could leave the job to thousands of little creatures who do an incredible job of creating black gold for your garden. Worm farming is a really rewarding way to add nutrients back to the garden. Unlike composting, you are intentionally utilising the services of living creatures and therefore there is a responsibility to ensure you keep them alive and well so they can do their work in prime health and give you the best quality worm tea which makes a fabulous liquid feed for your plants, and worm castings that are great as a soil conditioner to improve the soil in many ways including improving the structure and adding nutrients in a form plants can access easily.

To start with you need to make sure you get the right kind of worms as the worms you find lurking in your soil are different from those who enjoy living in your compost. The worms in the garden prefer to live in the soil and eat the soil, releasing the nutrients within it in an available form for plants, creating tunnels as they do which improves the soil structure and aeration. Compost worms on the other hand live above the soil in a habitat of moist, composting materials and need to eat loads of organic material, which makes them perfect for keeping in a worm farm.

The compost worms you need are called Tiger worms (Eisenia fetida) and are short and red with yellow stripes. You can buy them from your garden centre in a box of 1000 for a reasonable price or find a friend with a healthy farm who is willing to share.

Worm Farm

The farm

They also need a good home where they can live and work. The general design for a worm farm is a multi-layered waterproof structure. It is a good idea to avoid farms in the colour black as on a hot summers day this can overheat the farm and harm the worms or set it up in a shady spot. It also needs good airflow, and a lid is a great idea to stop excessive rain from drowning them. It does need to remain damp in there, so it may need a light spray with water regularly to keep the worms happy.

Top Layer

The top layer of the farm is where the worms eat all the lovely organic materials you add to the farm. The worms can be rather hungry and can eat half their weigh in food each day. Feed them an equal mix of greens and browns. Greens being high nitrogen vegetable scraps, teabags, coffee grounds, lawn clippings, weeds and green leaves, and the browns being carbon rich shredded paper, cardboard, eggshells, dry leaves, sawdust, tissue and even the contents of the vacuum cleaner!

Avoid giving them fats and oils, citrus, onions and garlic, meat and dairy products, bread, pasta and other processed foods. If you chop the food into small pieces or run it through your blender then the worms will be able to eat it faster. They should eat the most of what you give them in about 24 hours so don’t over feed and start slowly with a new farm. As the population grows they will be able to eat more.

Middle Layer

The middle layer of the farm is where they will live when they’re not eating. This bedding layer needs to be free draining and filled with materials like coir, shredded paper, straw, compost, dried leaves. It needs to be a moist environment to keep the worms happy.

Bottom Layer

The lower level is where you can harvest the by-products of the farm and the reason for having it. This is normally a barrier where the liquid can drain through, but not the worms. The liquid tea is easily collected through a tap at the bottom of the farm. It makes a rich plant fertiliser and should be diluted to the colour of a cup of tea – generally around 1 part to 10 with water.

Castings take longer to accumulate, and you should be able to harvest a useful amount every couple of months, depending on the size of your farm. You will be able to tell when to do this, when the bedding material is no longer recognisable from what you started with. Collection can be a little tricky as you need to separate out as many worms as possible. It could be as simple as pushing aside the top layer of bedding and harvesting what is below. Or you can set up a new bedding layer above the old one if you have a tray system or put new bedding on one side of the farm and feed them on that side. They will soon migrate to the new area, leaving the old area free to harvest.

The worms are light sensitive, so you can empty the spent bedding into a mound in a sunny spot and slowly remove the outer layers of the mound as the worms seek the dark centre. Eventually you’ll have a small pile of worms and bedding to pop back in the farm. Worm castings can be used directly on the garden and your garden will love it.