Are grubs harmful in flower pots? Fight them with a simple trick

As if it wasn't enough that the larvae can be found every now and then in the garden bed, to make matters worse, they sometimes also appear in pots or flower boxes. Are grubs harmful in flower pots? Should they be removed immediately or do the plants not mind temporarily sharing their habitat with the intruders?

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In principle: They can stay in the ground, but they don't have to. However, you should also be sure that it is really a type of larvae that will not harm the roots.

Foto: Karel Bock/ Shutterstock

The larvae of various beetles are called grubs. Some of them feed exclusively on plant remains and waste in the soil, as long as these are available. Others also snack on the plant roots, which in the long term leads to the death of the plant.

So grubs in the flower box or pot are only a thorn in the side if they are the latter. These include the larvae of:

  • cockchafer
  • June beetle
  • Garden leaf beetle, theespecially lawnsaffected
  • Curlew beetle
Photo: MakroBetz/Shutterstock

But thick, white grubs in the flower pot can alsobe of beneficial organisms. This includes:

  • Rhinoceros beetle
  • Rosenkäfer

The only way to find out whether grubs in flower pots are harmful is to check what your pest is. This can usually be recognized by the way the respective larva moves, as these differ between the individual species.

A notice:So that the useful larvae do not attack the roots sooner or later due to starvation, it is worth working dead plant parts into the soil from time to time and feeding the grubs, so to speak.

How to get rid of beetle larvae

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If it is a harmful species or you just want to get rid of it, you can use just one remedy to combat grubs in the flower pot. In general, combating them in containers is much easier than in the field.

The “means” we mean are your own hands (preferably protected with gloves because you have an aversion to the fat larvae). Since all the invaders are in a limited area, it won't be difficult to get to them all. This would be a little more difficult in the bed, which is why nematodes are often used.

Fighting grubs in the pot - it's that easy

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All you have to do is collect the beetle larvae. Since you've probably already noticed the grubs when you were about to plant a new plant, this is even easier because you don't even have to take the plant out. However, if you only became aware of it at a later point in time.

  • Remove the plant from the pot.
  • Shake off the soil from the root ball (and probably one or two larvae).
  • Go through all the potting soil and collect the larvae. A sieve could also be helpful.
  • If the soil and plant are free of grubs, you can (re)plant them.

Tip for large potted plants

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If the grubs are in a very large container (e.g. a palm tree) and you don't want to go through the hard work of removing the plant, you can also use nematodes to destroy the grubs in the flower pot. You can find out how to use these correctlyread here.

Or how about a (harmless) trap?

  • Fill a bucket with horse manure or compost.
  • Dig it into the garden soil anywhere.
  • Place the affected plant and its pot next to it.
  • Leave the bucket where it is until fall.
  • Since the horse manure/compost is tastier than the boring potting soil, the beetle larvae will quickly migrate there.

Prevent grubs in flower pots

You can take preventative measures to prevent an infestation from occurring in the first place. How can you stop the beetles from laying their eggs in the tubs and boxes?

Plant protection in this regard begins in April, when these insects are in the egg-laying phase.

  • Make the earth's surface less attractive. If it's nice and loose and fluffy, that's of course ideal for laying eggs. Instead, a layer of gravel will prevent them from doing so.
  • If you don't want to distribute and remove stones every time, you can simply use fleece.
  • The smell of certain plants also has a deterrent effect on the beetles, especially if they can act in the form of a concentrated decoction. This doesn't harm the plants at all. Especially thoseJauche from Rainfernhas proven to be very effective.