A hundred grams of chopped leaves steeping in a litre of rainwater, or a kilo of them bubbling in a barrel for a week: infusions, decoctions and fermented teas turn nettle, comfrey, horsetail and garlic into fertiliser and treatment. Watch the fermentation, which ends when the bubbles stop, and the whole garden’s feeding costs almost nothing.
Some plants will help others to grow, fend off diseases or repel insects and pests. Famous in organic farmer circles, their active ingredients can be extracted in various manners. They are all easy to produce, organic and affordable.
The same plants can be turned into very different products depending on how you extract them. This table sums up the four routes described below, with the quantities given in the article.
| Preparation | How it is made | Quantities | Best known for |
|---|---|---|---|
| Infusion | Steep the plant in boiling water, filter, then dilute with water and spray | 100 g of plants per 1 litre of rainwater, left to steep a full day | Repellent: garlic against aphids, snails and carrot fly; chamomile against cabbage moth |
| Decoction | Macerate 24 hours in cold water, boil 20 minutes, filter and spray directly | 100 g of fresh plants or 20 g of dried plant per 1 litre of water | Fungicide and insecticide with garlic; absinthe against slugs, aphids and ants |
| Fermented tea (maceration) | Chopped plants left to ferment, stirred often, until the bubbles stop | 1 kg of chopped plants in 10 litres of water, 5 to 10 days | Fertiliser and treatment: nettle for nitrogen, comfrey for young plants, horsetail as a fungicide |
| Garlic planted as a companion | Plant the cloves at the foot of the tree, no preparation needed | — | Its sulfur helps avoid fungal diseases, notably peach leaf curl |
| Coffee grounds | Used grounds worked into the soil, or sprinkled over an anthill | — | Nitrogen-rich feed for indoor pots, and a way to move ants on |
All of them are easy to produce, organic and cost next to nothing.
As its name shows, this method is simply to let a plant infuse in boiling water. After a given time, it is filtered and then cut with water for spraying on plants.
An infusion prepared from garlic cloves can thus be used to prepare a repellent against aphids, snails, and the carrot fly…
Chamomile both fortifies plants and repels insects (against cabbage moth and aphids, just like absinthe).
A decoction prepared from garlic is a fungicide and an insecticide, absinthe helps fight against slugs, aphids, ants…
After having macerated the plant for 24 hours in cold water, boil the mixture for 20 minutes, filter it and then spray it directly.
Maceration is one step to prepare fermented tea to spray on leaves or to add in water during the regular watering to stimulate the growth of the plant.
With high levels of nitrogen, fermented stinging nettle tea is a famous fertilizer. It also helps fight against downy mildew, tomato blight, powdery mildew and aphids.
Fermented horsetail tea has the same effect as a fungicide. With high levels of potassium, calcium and phosphorus, fermented comfrey tea makes for the ideal fertilizer for young plants (especially vulnerable seedlings), roses and fruit vegetables.
Garlic contains sulfur which is key to avoiding fungal diseases. Plant it at the foot of peach trees against leaf curl.
Coffee grounds are nitrogen-heavy fertilizer material as well, with plenty of minerals. It is very easy to use it to enrich the soil in your indoor pot arrangements and plants. You can also sprinkle it over an anthill to make its inhabitants flee to other lands.
Laure Hamann
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