Compost Tea for Bonsais

Compost is plant and animal-based organic matter decayed organically by bio-degradation. Compost tea is generally made by adding water to compost in a ratio of 4:1: to 10:1, and allowing the water to leach through the compost. The collected liquid, compost tea, is an effective and potent organic liquid manure.

However, making compost is a long process that takes few months. Here is a recipe for a type of compost tea, which can be made much faster. This compost tea is particularly suitable for bonsais and bonsai growers.

Pruning branches and leaves of bonsai plants is a regular activity in bonsai growing. As the bonsai soil is rich in nutrients, a lot of weeds come up around the plant and grow vigourously. Removing these weeds from the pots is also a regular (and rather boring) activity. Small amount of nutrient-rich soil also come off with roots of the weeds, while pulling them out.

Using these and any other green matter – leaves of plants or weeds pulled from the home garden – we can make compost tea, by allowing these to decay in water. A combination of leaves, grasses and soft & hard weeds will result in a good mix of nutrients in the final liquid. It may be beneficial to add leaves of tall trees also, if possible, as their roots run deep and tend to pull up multiple minerals from the earth.

200 litres is a good amount to make at one time. Fill two thirds of a 200 litres (plastic) drum with water, and put the green matter into the drum. Keep dumping the greens almost till brim of the drum, while they are still green and fresh. Be generous in adding the leaves and soil that are collected when you clean the floor of your bonsai garden. The soil that has leached to the floor contains nutrients that were fed to the plants and is also a rich source of beneficial micro-organisms. Stir occasionally. After a while, the liquid begins to froth and bubble and smells strongly agricultural. The more it bubbles, the better it is: shows the presence of more micro-organisms. A little longer and it settles down. In warm weather, the liquid manure (compost tea) would be ready in about two weeks.

DO NOT PUT KITCHEN WASTE INTO IT. Vegetable peels and tea leaf waste are, of course, good sources of Nitrogen, and skins of fruits such as plantain contain good amount of Potassium. A practical method would be to dry these in the sun and feed to the plant. Or else decay them in water separately, as the resulting liquid could become quite smelly.

A better idea is to use an additional 200 litres drum. One drum is used to dump the green matter, as previously described. As the compost tea gets formed, the top liquid is transferred to the second drum. Continue to dump the green matter into the first drum. The compost tea in the second drum can be given to the plants.

I do not know the botany and chemistry of it, but do know that compost tea is an excellent fertiliser for bonsai plants. It works! It keeps the plants healthy. Ample quantities of the tea can be given to the bonsai plants every day. It may be diluted for use with water. One part tea to two parts water is a good ratio. Dilute until it is the colour of light (drinking) tea. I have given the compost tea without diluting even to mame bonsais, and have not noticed any ill effect so far.

When the first drum is about half full with organic residue, which takes 6 months to 1 year depending on how much you put into it, empty the drum and spread the contents on the ground. Dry it in the sun. Remove the solid residues – the matter that has not got composted yet – and throw into a compost pile, as described below. The leftover is black gold literally: excellent compost which can go back into the pots. This indeed is a full circle feedback mechanism.

I go one step further. I have built a small compost pile on the ground nearby. When the leaves in the first drum decay, which takes one to two weeks (some leaves take longer), branches, leaf stems and other matter that do not decay fast are left. I pull out these from the drum and put in the compost pile, along with other organic matter. The pile keeps building up for 6 months or so. Allow some more time, after which I break up the compost pile, thus a total reuse of all organic wastes from the bonsai garden!

During traditional compost making, temperature of compost piles rise high enough to kill harmful pathogens, weeds, fly larvae etc. This does not happen here, which is a drawback in this type of compost making. If you are skeptical about this, avoid adding weeds, add only leaves and other cuttings.

Try not to touch the liquid compost tea with bare hands, rather use rubber gloves. It can be strong smelling and difficult to scrub off.

Tip: In case you happen to touch the liquid and the fowl smell does not go off even after washing with soap, try washing with tooth paste (after washing with soap).