The Content Of The Article:
- Origins and history
- Mode of action of weed killers
- Weed killer with biological agents
- How to use biological weed killer properly
- Chemical weed killer
- Lawn herbicides
- Calcium citrate against weeds and seeds
- Proper handling of herbicides
- Prohibited applications
- Weed killers should always be the last option
Origins and history
The old Romans were already struggling with weeds, but it was not until about the middle of the 19th century that weed killers replaced the tedious manual labor of hacking and haying. First, iron sulphate or sulfuric acid was released as a herbicide onto the weeds, and in the 1920s also sodium chlorate, long sold as "weed ex". The impact on the environment was secondary, you saw mostly the success.
Since the 1940s, there is the highly effective compound with the name 2,4-D, which is still present in grass weed products and fights exclusively dicotyledonous weeds. To this day, many substances have been added, which are approved as weed killer in the home garden. They first came into the discussion due to the massive use in the Vietnam War, where close relatives of the 2,4-D as "Agent Orange" destroyed entire rainforest areas and massively harmed humans because of dioxin contamination. Thanks to stricter environmental regulations and a heightened awareness, more and more funds are being put to the test today.
Mode of action of weed killers
Most weed killers act as contact herbicides on or over the green leaves. In the case of so-called chemical burns one can almost watch the leaves wither within a short time, leaves that are not wetted remain intact. The result is like a chemical weed that removes all above-ground parts of plants like a hoe. One-year old weeds are usually completely, root weeds, however, drive out after some time again. Since the spray mixture must dry on the sheet and must not be washed off, dry weather accelerates and improves the effect. The active substance remains outside the plant or is at most locally absorbed by the leaf. Blade etchers work at temperatures as low as ten degrees.
Contact herbicides discourage the leaves of weed plants
Systemic agents are absorbed by the plant after wetting of the green leaves, but then transported with the sap flow in all parts of the plant - even in unaffected leaf lots and the root tips. The funds hinder the metabolism and are therefore also called Growth Substance Herbicides. The result is a complete destruction of the plant, whose metabolism is hochgepowert until it dies - it grows to death. The success, however, can only be seen after days. Since the plants have to work actively for the transport of active agents, the agents only work reliably at higher temperatures, and in the case of sultry growth weather the best. The glyphosate under discussion is one of these agents.
So-called soil herbicides combat dormant seeds. The funds have little significance in the garden, but are often part of lawn herbicides, which also act to a small extent on the roots.
Most weed killers do not differentiate between good and evil and indiscriminately go for anything green. These total herbicides should only be used if there is sufficient distance between weeds and crops, if the crop plants can be covered in the bed or sprayed in complete calm. Selective herbicides are rare. The input mentioned 2,4-D, for example, leaves monocotyledonous plants, including the grasses.
Weed killer with biological agents
Even if no herbicide is permitted in organic farming, there are remedies for the home garden with natural or nature-inspired active ingredients such as acetic acid or pelargonic acid. The best known are "Finalsan AF Weed Free Plus" (Neudorff) with the active ingredient mix of pelargonic acid and maleic hydrazide, the "Herbistop AF organic weed killer" from Compo with pelargonic acid and "Celaflor NaturenBio weed free" based on acetic acid.
How to use biological weed killer properly
Chemical weed killer
Whether 2,4-D, MCPA, dicamba or glyphosate: That sounds kind of poisonous and even "Agent Orange" often haunts the back of your mind: The chemical weed killers like Roundup & Co. are the most discredited, but they also work on the best and eliminate weeds with just one application almost completely. Glyphosate is a development of Firm Monsanto and since 1974 as "Roundup" in the trade. It is now distributed by over 40 companies and is also included in other weed killers such as "Vorox Weed Free Direct".
When the green carpet is riddled with weeds, lawn herbicides help. They leave grasses alone and only go on the dicotyledonous weeds. However, this means that even couch grass and millet sprouts are spared. Lawn herbicides are sprayed or poured, with spraying going faster and consuming less resources. The weeds turn brown after a few days and seem to evaporate.
Prerequisite for a good effect are (night) temperatures of over ten degrees.If it is colder, the plants are far too sluggish and do not transport the active ingredients to the root tips. Mow the lawn first, then wait four more days for treatment to close the cuts on the stalks.
Clover in the lawn can be combated with selective herbicides
Tip: High-quality grass mixtures can prevent weeds. They are more expensive, but save trouble and follow-up costs. Brand seed forms a much denser lawn in which weed seeds hardly find any gaps to germinate. The cheap mixes grow well in the first year, maybe in the second. But then their forage grasses show their true face: no dense scar, but gaps. Then the former budget-conscious hobby gardeners start investing a lot of money in care products and equipment, which then only temporarily eliminates the symptoms of weed growth.
Calcium citrate against weeds and seeds
Lime nitrogen is a nitrogen fertilizer that is sold as a "perlka". In addition to the fertilizer effect, it is also a weed killer and even kills weed seeds. The effect is based on cyanamide, which is produced in moist soil. It is not a highly toxic cyanide, although it sounds similar. Cyanamide is corrosive and kills even low weeds, in case of wrong dosage but also the grasses. Cyanamide is converted in the soil first to urea and then to the plant nutrient nitrate.
Lime nitrogen is used to control weed seeds before sowing
The poor dosage option makes lime nitrogen for lawn fertilization and thus unsuitable for controlling the Rasenunkräuter. As a basic fertilizer for seedbeds, however, it is ideal, because the bed then goes after two weeks weed-free into the season. That's how long it takes, for example, to convert cyanamide completely into harmless urea.
Proper handling of herbicides
Weed killers are available as a concentrate for dilution or as ready-to-use agents (AF) that can be poured or sprayed immediately - casting being faster and especially suited for small areas. In contrast, spraying consumes less of the medium. After treatment, it should remain dry for a few hours so that the active ingredients are not washed off again. Never spray with wind, drifting can damage adjacent beds. Residuals in the syringe must be sprayed again on the surface, they must not land in the sink!
Weed killers only fight weeds with sufficient leaf mass. Even if it is difficult, you have to let Giersch & Co. grow until they have enough leaf area. Then you spray this dripping wet. It should be understood that pets do not get a spray. These may only be in the garden when the spray coating has dried. Root weeds often come back, as there are always some non-expelled root pieces, which are therefore spared. After re-treatment two weeks later, the weeds are then defeated.
For spraying lawn herbicides, the lawn must be dry. When deploying, walk backwards so that you do not step on the treated surface and the agent may deposit on your rubber boots elsewhere, where it is undesirable. Clean used syringes immediately after treatment, because even small residues can damage subsequent cultures.
Herbicides applied indoors or in the garden must be approved for this area of application. The large containers for professional horticulture or agriculture sold in the land trade do not have this approval and may not be acquired or used by persons without appropriate evidence of expertise - for example, a vocational training as a gardener or farmer. If, on the other hand, you hire a landscaping company to look after the garden, these products may also be used in the home garden for professional gardening.
Damage to the groundwater is not to be feared due to the rigorous testing in the course of the state-of-the-art approval procedure for plant protection products - but only if the funds are used correctly. It is usually the application error and too generous use in crops, get through the repeatedly herbicides in the sewers and finally land in the sewage treatment plant, where they can not be mined. This is only possible on "biologically active" surfaces, which is why herbicides may only be used on cultivated areas such as beds or lawns.
Weeds on paved areas must not be combated chemically
One is temptingly comfortable, but absolutely forbidden: weed killer on paths and other sealed surfaces. It is essential to observe the instructions for use in terms of dosage and application period. A violation can be fined five times. The risk of being caught may be low, but many communities are now even sending staff to check in the evening. The full legal penalty amounting to 50,000 euros hardly pays one of those caught, but also the realistic penalties of a good 8,000 euros are not worthy of a breach.
Numerous suggestions and recipes for home-made home remedies are also circulating on the Internet, for example from vinegar, salt or other supposedly biological active ingredients. According to the Plant Protection Act, every plant protection product, including a weed killer, must be approved for every area of application. The mixed broths are not. On the one hand, this produces a product that is not even a plant protection product and, on the other hand, a preparation that is not approved for the intended use - a double misdemeanor.
Who really wants organic, pours boiling water from the kettle over the weeds, gives him a heat shock with a flaming device or simply pulls it out of the ground manually.
Weed killers should always be the last option
For many hobby gardeners only weed-free gardens are beautiful and that without work. However, the most thorough and environmentally friendly weed control is and remains handcraft. And why not leave a few weeds beside the compost or in another corner? Insects are happy about the nectar fast food and the garden does not have to look neglected.
Even if the Federal Office of Consumer Protection and Food Safety (BVL) as a regulatory authority thoroughly examines each pesticide and the residual amounts are well below a limit even if handled properly, you would like to have neither glyphosate nor other active ingredients - whatever detours - in the food. But in the end every hobby gardener has to decide for himself if he wants the admittedly comfortable chemistry in the garden or not.