Green Manure and Compost Activators

Grow Your Own Compost – Green Manure

If you get keen on composting, and want to import as little extra material as possible, grow some plants specially for your compost pile. Or include living compost in areas of your garden.


Living compost

Living compost — or green manure — is a crop that is grown specifically to be chopped down and turned into the soil. Legumes, members of the pea and bean family, are particular favourites because of their ability to collect nitrogen in their root nodules, so when they are returned to the soil they add high levels of vital nitrogen. Some grasses are also useful because they have spreading and penetrative root systems that help improve the structure of the soil.


Cut and compost

growing Comfrey for green manure Sunflowers make excellent bulk for a compost heap, particularly worth growing if you have quantities of grass mowings to compost as the sunflowers add valuable bulk, aerate the heap and are extremely high in fibre to balance protein-rich grass mowings.

Marigolds (Tagetes minuta) are also worth growing for compost. While they grow they act as effective pest deterrents — particularly for soil pests such as eelworm — and also prevent weed growth because of the enzymes they produce. When you pull them for compost you add valuable bulk to your heap.

Comfrey is in a class of its own. Its strong roots can dig as deep as 2m to gather vital minerals which are made available to other plants when comfrey leaves are composted. It gets compost going, is an important source of potassium for organic gardeners, and grows so quickly you can crop the leaves every six weeks or so. And sturdy perennial plants last many years.


Compost Activators

A compost activator kickstarts or speeds up the process of composting. It is a material that encourages biological activity in the heap. Activators such as young nettle plants increase the nitrogen and micro-nutrient content of the heap, providing extra food for micro-organisms.

Others such as humus-rich garden soil introduce organisms that break down raw organic matter.

When you are starting a new compost heap its a good idea to add an activator fairly near the bottom of the pile, then add more at regular intervals. Some people swear by a layer of compost from a recently finished heap, or a layer of good topsoil. Thin (5cm-10cm) layers of nitrogen-rich grass mowings are popular, or strawy muck from a poultry house.


Manure is a rich source of plant nutrients and bacteria, but always partially dry it first as very wet muck will slow down the initial composting process rather than getting it moving. Human urine is an excellent activator because it contains plenty of nitrogen and loses potency less quickly than most animal manures. If there’s a baby in the house empty the potty on the heap regularly, and young boys rarely need encouragement to pee straight onto the heap.

Comfrey and seaweed are dynamic accumulators, which means they collect and store vast amounts of nutrients, and they decompose swiftly to activate your compost. Horsetail also helps speed composting activity—either chop it up (don’t add the roots) or leave the hollow stalks to rot slowly, so adding aeration to your heap.

10. December 2010 by admin
Categories: Compost Making, Soil Cultivation | Tags: , , | Comments Off on Green Manure and Compost Activators


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