Garden heroes: Horsetail and nettles are true plant saviours

An ailing plant is more susceptible to pests, just as we are more prone to disease when our immune system is weakened. There's no need to resort to pesticides, however, as plenty of natural remedies effectively boost plant health and prevent infestations.

"No matter what problem you have in the garden, you don't need pesticides," says Corinna Hölzel, an expert on pesticides with the German Federation for the Environment and Nature Conservation (BUND). She recommends to boost plant health using liquid manure, which you can make yourself from nettles or horsetail, for example.

Put the shoots in a large container filled with water. "Place it in a sunny spot and wait for a few days," says Hölzel. Using a watering can, pour the slurry on the plants so that it reaches the roots. The manure "strengthens your plants and makes them resistant to diseases and insects."

Liquid manure can be effective against:

\- Whiteflies and vegetable flies that suck the plant sap from cabbage, beans, cucumbers and tomatoes. Some fly larvae eat the roots of onions and carrots. Nettle manure strengthens and protects them.

\- The Potato beetle can destroy potato plants, tomatoes or eggplants and peppers. Use nettle manure.

\- Spider mites suck sap from cucumbers, pumpkins, beans, strawberries, berry bushes, fruit trees and ornamental plants. Strengthen them with liquid manure made from nettles, for example.

\- Powdery mildew: The fungal disease attacks vines, fruit, cucumbers, pumpkins, cabbage and ornamental plants. Use horsetail or garlic tea and nettle liquid manure.

\- Curl disease on peach and apricot trees: To control it, spray horsetail and nettle mixtures on the leaves.

Milk for combatting fungi and viruses

Your refrigerator is probably full of eco-friendly plant remedies, BUND says. Simply dilute fresh milk with water in a ratio of approximately 1:9 to fight mildew on cucumbers, pumpkins, cabbage and many fruit and ornamental plants. Spray the concoction on the leaves every two to three days and remove infested foliage straight away.

Skimmed milk sprayed on the leaves can prevent mosaic virus on cucumbers, pumpkins, courgettes, melons, tomatoes, peppers and beans.