Calcium cyanamide: Use in the garden and against moss/weeds

Year after year, the earth should deliver a diligent yield: crunchy vegetables, delicious strawberries, thick potato tubers and everything else that the gardener grows. Or just plenty of green blades of grass for the perfect lawn. Without unwanted herbs such as dandelions, daisies and co. And without moss anyway. Is it easy and, above all, close to nature? Calcium cyanamide is said to be a long-established magic potion.

What is calcium cyanamide anyway?

Calcium cyanamide has been produced industrially for more than 100 years. Our parents and grandparents used it for their vegetable gardens and lawns. It is still commercially available today, often under the name "Perlka". This name derives from its grain size. It used to be mainly in powder form, but nowadays it is offered in pressed form as granules for safety reasons. In a chemical process, the calcium carbide produced from coal and limestone binds the nitrogen that is abundantly present in the air. Calcium cyanamide consists of about half lime, one fifth calcium cyanamide (CaCN2) and some nitrate.

How do its active ingredients reach the plants?

The nitrogen in the calcium cyanamide is initially not immediately available to the plants. Only in the soil is this compound converted into substances available for plants by microorganisms in interaction with water. This happens gradually and takes some time. In the first step, slaked lime and the toxic and water-soluble substance cyanamide are produced. It is precisely this cyanamide that develops the herbicidal effect, which is why the calcium cyanamide is particularly popular with hobby gardeners. About two weeks later, the microorganisms have converted the toxic cyanamide into completely harmless urea and ultimately nitrate. Nitrate can be taken up by the plants through the roots together with water and used as a nutrient. No toxic residues remain in the soil.

What is calcium cyanamide good for in the garden?

Thanks to its components, calcium cyanamide can have a variety of effects in the garden, on the bed or on the lawn:

• as a long-term fertilizer for nitrogen, it brings rapid growth
• as a fungicide against various fungal diseases
• as a herbicide against weeds and moss
• as an insecticide against numerous pests and against snails
• for lime supply
• as a compost accelerator for rapid and thorough decomposition
• as a soil improver through lime enrichment
• as a companion to green manures after harvest

Calcium cyanamide as fertilizer

This mineral fertilizer supplies the soil with nitrogen and lime. Nitrogen is a nutrient that boosts growth and ensures a good yield regularly and reliably. The lime, on the other hand, counteracts the acidification of the soil and at the same time improves the soil structure. Microorganisms do not like acidic soil, but as residents of garden beds they are indispensable. They are the ones who, through their transformation processes, ensure a fine, crumbly, loose and nutrient-rich soil.

Long-term effects of calcium cyanamide

After the application of calcium cyanamide, the nitrate content is immediately available to the plants. The microorganisms need time to completely process the remaining calcium cyanamide for the plants, from cyanamide to ammonium and this in turn to nitrate. As long as the ammonium has not yet been converted into nitrate, it remains in the soil. It is hardly affected by leaching. The long transformation time is not a disadvantage, it is much more ideal for the plants. You don't need the nutrients all at once, but distributed more or less evenly over the entire vegetation period.

To ensure that the long-term effect of calcium cyanamide lasts even longer, dicyandiamide (DCD) is added to the calcium cyanamide. DCD is a by-product of the production of cyanamide and is referred to as a so-called nitrification inhibitor. It slows down the conversion process from ammonium to nitrate and thus contributes to the long-term effect of calcium cyanamide. The speed of degradation is also influenced by temperature and soil moisture.

Lawn care and moss control

The lawn can also be fertilized with calcium cyanamide. It strengthens the turf and leads to a denser lawn. Another positive effect is the destruction of unwanted moss. This displaces the grasses and spreads more and more if nothing is done about it. He especially loves it when the lawn is in the shade and is often damp. However, applying calcium cyanamide to lawns is a bit tricky and therefore requires gardening experience or the desired effect will not be achieved. On the contrary, the lawn noticeably suffers from incorrect care.

• strictly adhere to the recommended dosage
• Distribute the granules evenly over the entire surface
• the grass must not be too wet during spreading
• Do not use calcium cyanamide on freshly seeded lawns

If you love your lawn, it is better to stick to these rules, otherwise the lawn owner will quickly risk a burnt lawn due to overdosing. If the stalks are too wet, many nitrogen granules stick to them and also lead to unwanted burns. And young grass plants are still too sensitive to calcium cyanamide. Although the lawn is recovering from the burns, it is no longer pretty to look at for a few weeks.

How does calcium cyanamide work against snails?

In some years, slugs are a huge nuisance in many gardens. Mild weather, hardly any natural enemies and frequent watering favors their spread. You can see them crawling around everywhere, devouring the leaves of plants in no time. They are so voracious that often only the root remains of a head of lettuce. Countless control methods are then used, but not all are promising or take effect far too slowly. More and more snails hatch from the many eggs that have been laid.

Calcium cyanamide works twice, against crawling snails and their eggs. So no more snail replenishment can hatch.

• 30 grams of calcium cyanamide per square meter are sufficient
• treat usual “snail spots” with particular care
• such as compost heaps, scrub and hedges
• repeat the application after a few weeks

Wireworms and tipula larvae can also be combated in this way.

Calcium cyanamide against fungal diseases

Clubroot is an extremely stubborn fungal disease that tends to affect cabbage plants. Unfortunately, it can hardly be combated effectively. Calcium cyanamide counteracts this by fighting the fungal spores in the soil. They are prevented from germinating, which means that the infestation is quickly contained. Apple scab spores are also successfully combated in this way.

Calcium cyanamide against weeds

The herbicidal effect of the calcium cyanamide unfolds right at the beginning of the application. The first substance that is formed during the conversion is the toxic cyanamide. It sinks a few centimeters into the ground and destroys all shallow-rooted plants. These are mostly unwanted herbs. The garden remains mostly free of weeds, the annoying and exhausting weeding is almost superfluous. Other plants are no longer crowded out or prevented from growing.

What calcium cyanamide is doing in compost.

A compost heap is handy. Any greens that don't end up on the plate end up in the compost heap. In return, after a while it gives us back the finest, nutrient-rich soil. Unfortunately, the rotting can last a whole year or even longer. If, on the other hand, calcium cyanamide is repeatedly sprinkled over the garden waste, this process accelerates enormously. The high lime content and the special form of nitrogen promote rotting bacteria. The compost heated up in this way is no longer suitable as a breeding ground for snails, maggots, pathogens and weed seeds. As a result, the garden waste turns into humus without flies and accompanying stench.

When is the optimal time for calcium cyanamide?

The granules can be spread and worked into the garden in the warm season from March to September.

• in good time before sowing or planting
• in spring two weeks before sowing
• in summer one week is enough
• sprinkle in the morning or evening
• keep the soil moist
• do not enter the bed during this time
• Keep pets away
• only after 1-2 weeks is the toxic period over
• in cold weather wait a few days longer before sowing
• Can also be used after cultivation for "soil cleaning"
• suitable for topping up the nitrogen supply
• do not use during plant growth
• then certainly not by inexperienced gardeners

The right dosage

The correct dosage must be based on the needs of the crops being grown. Strongly consuming plants need the most of it, about 30 to 90 grams of calcium cyanamide per square meter of cultivation area. Cucumbers and potatoes about 30 to 50 grams. Existing lawns are well supplied with about 20 grams per square meter. About 150 grams of calcium cyanamide is sprinkled into a composting facility about one square meter in size. After the new layer of compost has reached a height of 30 cm, calcium cyanamide can be added again. These values ​​are only guidelines. Be sure to observe the information on the sales packaging. If the dosage is not clear, it is better to ask your specialist dealer.

The calcium cyanamide should be spread as evenly as possible. Throw upwards from the wrist to all sides. This allows the granules to fly apart better and disperse evenly.

Attention: Observe precautionary measures!

Although calcium cyanamide is no longer offered as a fine powder that can be dispersed in the air and easily inhaled, it is not entirely safe to use. In the case of negligent and incorrect use, the toxic cyanamide in particular poses a danger to people and pets. If this substance comes into contact with moist skin or mucous membranes, it is harmful and causes chemical burns.

• Wear rubber or latex gloves when sprinkling
• must never come into view
• Keep children and pets away
• Keep calcium cyanamide out of reach and according to regulations
• Always read and follow the instructions on the package before use

Calcium cyanamide and potted plants

Anyone who treats their garden plants with calcium cyanamide could also come up with the idea of ​​using it to make their potted plants happy. Although this idea is obvious, it is not recommended. In such a small space, it can quickly happen that the roots take up too much cyanamide before it can be converted further. The result is yellowed and dried leaves.

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