Make nettle decoction against aphids and weeds

With the broth of nettles, aphids can be fought in an environmentally friendly and biological way. However, the remedy is not a silver bullet, so the plants should be checked frequently for infestation. Nettle decoction is not only very effective in the early stages of aphid infestation. It can also be used against annoying weeds that grow between the paving stones, rolled surfaces or on the steps of stairs and are difficult to remove.

Which nettles are suitable?

nettles (utica) belong to the nettle family and are found almost everywhere in the world. We mainly have the Great Nettle (Urtica dioica) and the little nettle (Urtica urens) widespread. The upper plant parts of both species are suitable for preparing nettle stock, with the smaller species being considered the more aggressive. Harvesting is best done on a sunny day in early May, just before flowering. dead nettles

(lamium) belong to a different plant genus and are therefore unsuitable.

Use of nettle decoction

The smell and some active ingredients from the stinging nettle have a repellent effect on lice and spider mites. The brew also contains nutrients that strengthen the plants. Nettle decoction can also be sprayed on leaves and flower buds to counteract deficiency symptoms.

• Spray the leaves and shoots against aphids, spider mites and whiteflies
• Root bath when wilting potted plants
• also works against leaf chlorosis when sprayed on (as a fertilizer)
• acts as a bioherbicide against weeds

ingredients

The stinging nettle not only contains formic acid as a repellent, which the pests do not tolerate well, but also a whole lot of other plant active ingredients and nutrients. These are released into the brew and are therefore readily available for the plants. These include:

• iron
• other minerals
• Flavonoids (antioxidants)
• Carotenoids (antioxidants)
• Vitamins A, C and E
• phosphorus
• potassium and calcium
• Nitrogen
• Silicic acid (strengthens the cell walls and the immune system)
• Amines (in the stinging hairs) promote the green formation of the leaves

Materials needed

If you want to use nettle brew for pest control or weed killing, you need a few things that are usually available in every household with a garden:

• nettles
• water (preferably rainwater)
• Bucket and grid for covering
• Rose Scissors
• possibly blender
• garden gloves
• Sieve

Pick nettles

Which gardener does not know this: In the spring, nettles grow in abundance in the beds, under trees or on the compost. But the unloved plant is not only annoying, it can also be harvested wonderfully to produce a natural and absolutely biological pesticide. The nettles can be pulled out or cut off as painlessly as possible if the gardener is wearing gardening gloves.

• Time: in the spring before flowering
• only use leaves and soft plant parts
• the bigger the leaves, the better
• Half fill the bucket with the nettles
• Chop up the leaves and stems with rose shears

start the brew

The smaller the nettle leaves are cut, the better they can decompose and release their active ingredients into the water. Rainwater is best for topping up, but you can alternatively use normal drinking water from the garden hose.

• Amount of nettles: about 1 kg
• Amount of water: about 10 l
• allow to wilt for about 8 hours before pouring water on
• Storage location: shady and protected from rain
• Secure buckets with a grid (so that no animals or leaves fall in)

In principle, there are two different approaches to the nettle brew. Gardeners have had good experiences with both variants. Which approach you choose is a matter of taste. When it comes to homemade herbal broths, the motto is always that you can and may experiment a little in order to get the best results.

cold water extract

The plant parts of the stinging nettle are placed in cold water (rainwater) for a few hours. Then the solid components are sieved off and the nettle brew can be used immediately.

• minimum soaking time: 12 hours
• maximum exposure time: 48 hours
• the brew must not yet ferment strongly

hot water extract

For a nettle broth, the chopped plant parts are placed in water for 24 hours and left to infuse. Then boil the entire brew (including the leaves) in a large pot.

• about 1 kg of fresh nettles per 10 l of water
• alternatively 150 g dried nettles
• simmer gently for about 30 minutes
• cooling down
• sieve off solids
• dilute
• usable immediately

Application

After two days, the nettle brew can already be used as a biopesticide (against vermin) and bioherbicide (against weeds). The cold water extract can be used immediately. Hot water extracts should not be applied directly to the leaves, but diluted beforehand.

• Dilution: 1:5 to 1:10
• Outdoor plants: remove coarse solids, finely chop fine residues with the immersion blender
• Pour into a watering can with a shower attachment
• Pour directly over the leaves of the plants
• for indoor plants: filter the broth through a sieve or an old kitchen towel
• Pour into a flower spray bottle and spray on the leaves (including the underside).
• Spray at least once a day
• Repeat the process for at least three days in a row
• if there are no longer any aphids, spray a few more times anyway
• repeat the procedure after about two weeks (follow-up generation from eggs)

nettle manure

After a few days – or sooner if the brew is in the sun – the mixture begins to ferment vigorously. This can be recognized by the fact that foam forms on the water surface and the broth smells unpleasant. By this time, substances have already formed that would cause burns on the leaves and fresh shoots of plants. However, the fermenting nettle brew does not have to be poured away. Just let it sit for a few more days (about two to three weeks total) and stir once a day to form a nettle slurry. The fermentation process should be completed before use. This can be seen from the fact that foam no longer forms.

Which approach for which application?

Many instructions use different names for the individual batches and standing times of chopped nettles in water and swear by one or the other variant. The difference between a nettle broth, a broth and nettle manure is not that big:

• even brief preparation in cold water releases ingredients that are effective in combating pests (called nettle decoction or cold water extract)
• subsequent boiling of this mixture is usually referred to as nettle broth (hot water extract or tea)
• boiling large amounts of the nettle-water mixture is usually very cumbersome
• in the case of nettle manure, the mixture has stood in a warm, sunny place for at least two weeks and fermentation is complete
• Nettle manure can also be used to combat aphids and weeds
• only spray or water diluted (at least 1:10) on the plants

Conclusion

Nettle stock is ideal for the biological control of sucking pests and weeds in the garden. There are several ways to make the mixture. Soaked in cold water, the nettle decoction can be used undiluted after just one or two days. Hot water infusions and nettle manure alternatives are just as effective. However, they must be diluted with water at least 1:5 before use, in order to then be sprayed or poured onto the leaves of the plants.

Learn more about plant pests