With the stock of nettles, aphids can be combated in an environmentally friendly and biological way. However, the agent is not a silver bullet, so the plants should be checked frequently for an infestation. Nettle stock is not only very effective in the early stages of aphid infestation. It can also be used against annoying weeds that spread 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 small nettle (Urtica urens) widespread. The upper parts of the plant of both types are suitable for making nettle stock, with the smaller type being considered to be the more aggressive. Harvesting is best done on a sunny day in early May just before flowering. Dead nettles (Lamium) belong to a different genus of plants and are therefore unsuitable.
Use of nettle stock
The smell and some active ingredients from the nettle have a protective effect on lice and spider mites. The brew also contains nutrients that strengthen the plants. Nettle stock can also be sprayed onto leaves and flower buds against deficiency symptoms.
- Spray leaves and shoots with the brew against aphids, spider mites and whiteflies
- Root bath when wilting potted plants
- sprayed also works against leaf chlorosis (as fertilizer)
- acts as a bioherbicide against weeds
ingredients
The nettle contains not only formic acid as a defense substance, which the pests tolerate poorly, but also a whole host of other plant substances and nutrients. These are released into the brew and are therefore easily available to the plants. For this
belong:- 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 prepare nettle stock for pest control or weed killing, you need a few things that are normally available in every household with a garden:
- Nettles
- Water (preferably rainwater)
- Bucket and grid for covering
- Rose scissors
- possibly hand blender
- Gardening gloves
- Sieve
Pick nettles
Which gardener does not know this: In the beds, under trees or on the compost, stinging nettles grow en masse in spring. But the unloved plant is not only a nuisance, it can also be wonderfully harvested 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 are, the better
- Half fill the bucket with the nettles
- Chop up the leaves and stems with the rose scissors
Tip: If you harvest nettles in the wild, you should cut each individual plant in the middle of the stem. Because this way the nettle grows back faster.
Prepare the brew
The smaller the leaves of the nettle are cut, the better they can look
decompose and release their active ingredients into the water. Rainwater is best for filling up, but you can also use normal drinking water from the garden hose.- Amount of nettles: about 1 kg
- Amount of water: about 10 l
- Let wither for about 8 hours before pouring water
- Storage location: shady and protected from rain
- Secure the bucket with a grid (so that no animals or leaves fall into it)
In principle, there are two different approaches to stinging 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.
1. Cold water extract
The plant parts of the nettle are placed in cold water (rainwater) for a few hours. Then you sieve off the solid components and you can use the nettle stock immediately.
- Minimum soaking time: 12 hours
- maximum exposure time: 48 hours
- the brew must not yet ferment vigorously
2. Hot water drawer
For a nettle broth, the crushed parts of the plant are placed in water for 24 hours and left to infuse. Then you boil the entire brew (including the leaves) in a large saucepan.
- about 1 kg of fresh nettles per 10 liters of water
- alternatively 150 g dried nettles
- Simmer gently for about 30 minutes
- cooling down
- Sieve off solid components
- dilute
- usable immediately
use
After two days, the nettle stock can be used as a bio-pesticide (against pests) and bio-herbicide (against weeds). The cold water pull-out can be used immediately. Hot water extracts should not be applied directly to the leaves, but should be diluted beforehand.
- Dilution: 1: 5 to 1:10
- Outdoor plants: remove coarse solids, chop up fine residues with the hand blender
- Fill 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 the leaves (including the underside)
- Spray at least once a day
- Repeat the process for at least three days in a row
- if no more aphids can be seen, still spray a few more times
- repeat the procedure after about two weeks (subsequent generation from eggs)
Tip:
Always spray nettle stock on a cloudy day. If you spray the brew on the plants in bright sunshine, you have to expect burns on the leaves.Nettle manure
After a few days - or earlier when the brew is in the sun - the mixture begins to ferment strongly. This can be recognized by the fact that foam forms on the surface of the water and the broth smells unpleasant. At this point, substances have already formed that would cause burns on the leaves and fresh shoots of the plants. However, the fermenting nettle stock does not have to be poured away. Just let it stand a few days longer (about two to three weeks in total) and stir once a day so that a nettle manure forms. 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 approaches and standing times of chopped nettles in water and swear by one or the other variant. The difference between a nettle stock, a broth and a nettle liquid is not that great:
- Even a short exposure to cold water releases ingredients that are effective in combating pests (called nettle brew 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 control aphids and weeds
- spray or water only diluted (at least 1:10) on the plants
Tip: Cold extracts, teas and broths (hot extracts) of the nettle do not smell so strong, which is why they are particularly suitable for indoor 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 stock can be used undiluted after just one or two days. Hot water infusions and nettle manure are equally effective alternatives. Before use, however, they must be diluted at least 1: 5 with water and then sprayed or poured onto the leaves of the plants.