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Grubs are larvae of beetles that, depending on the species, persist in the lawn and can cause damage there. While some prefer dead root parts as food, there are specific species that use lawn roots as a food source. As a rule, they do not leave voluntarily, but stay for years if they are not fought. Calcium cyanamide is often mentioned among hobby gardeners, but does it really help against grubs?

grubs in the lawn

Only certain species belong to the grubs, which like to attack lawn roots for a long time:

  • Cockchafer (Melolontha)

May beetles like to lay their eggs in the lawn. Once the larvae have developed from this, they feed mainly on juicy grass roots from about the second year of life and cause damage for a total of around two more years.

  • Curlew Beetle (Amphimallon solstitiale)

Adult fallow beetles, also known as June beetles, appear on the lawn especially on warm June/July evenings. However, at two years, the generation period is shorter than that of May beetles.

  • Garden leaf beetle (Phyllopertha horticola)

The garden beetle is also often referred to as the June beetle. From May to the end of June they fly over lawns and lay between 30 and 40 eggs in the ground, from which the first grubs hatch after about three weeks. Their generation time is one year.

damage in the lawn

Anyone who does not see/recognize grubs or the adult beetles can identify an infestation of certain types of damage in lawns and derive a need to combat them. The typical damage caused by a severe grub infestation looks like this:

  • Completely eaten grass
  • Loosely attached blades of grass that can be almost completely pulled out with your hands
  • Brown spotting
  • Large-scale dying of the lawn

Calcium cyanamide to combat

Experienced hobby gardeners and lovers of healthy, lush green and healthy lawns swear by calcium cyanamide.

In fact, for many years it has proven to be an effective control agent against grubs on lawns. It is made up as follows:

  • Around 50 percent lime
  • One fifth calcium cyanamide (CaCN2)
  • Rest is nitrate
  • effect

Calcium cyanamide is particularly important for the effect. It has a herbicidal effect, which is actually used against various weeds such as moss. But it is also poisonous for grubs, so that they die reliably after fertilization with calcium cyanamide. Other positive side effects are:

  • Curbs the spread of pathogens
  • Prevents root rot
  • Suitable for controlling other pests in/under lawns
  • Drives away snails
  • Has a sterilizing effect
  • Promotes the formation of humus and the uptake of nutrients by the lawn

NOTICE: Lime increases soil pH, which is conducive to healthy growth when it's too low, but can be detrimental when it rises above 6.5. Accordingly, it should not be given often and ideally only after a pH value measurement.


When dealing with calcium cyanamide to control grubs, some safety precautions must be observed and an ideal dosage selected. In addition, correct application helps to achieve maximum effectiveness against the pests.

protective measures

  • Only work with rubber gloves
  • Avoid contact with mucous membranes (especially eyes)
  • Keep children and pets away from treated lawns for at least two weeks or choose an alternative home remedy (it must have rained heavily or been blasted at least once)

apply calcium cyanamide

  • Ideal: mix with some compost (the warmth encourages it to penetrate into the soil)
  • Soil should be moist
  • Dosage: around 20 to 25 grams per square meter (a tablespoon corresponds to around 20 grams)
  • Apply to entire lawn, including healthy looking areas, to reach all grubs
  • Distribute with the hand forward and slightly diagonally
  • Pay attention to even distribution

TIP: If no compost is mixed, a fertilizer spreader can also be used. This allows the amount to be applied more evenly and many garden owners find it more convenient.


Prevention is the best measure to ensure that grubs do not reappear in the long term after successfully fighting grubs. Here's what lawn owners can do to prevent a new pest infestation:

  • No night lighting of the lawn - light attracts the beetles and promotes egg laying
  • Surround the lawn with deeply dug curbs to prevent beetles from burrowing through the soil under the lawn
  • Work in a close-meshed root protection grid or wire inserts when preparing the soil for the lawn
  • Remove weeds quickly so that they do not provide an additional source of food
  • Regular scarifying/manual loosening of the soil deprives Engerlingen of its livelihood/optimal living conditions

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