Worms: Friends or Foe?

James Kimmingsin Wildlife & Ecology

Struggling with worms? Here is what we found that people are using. Although they're not the worst thing to find on golf courses, worm casts can ruin the aesthetics of a well-manicured green. However, there are also some benefits to worms.

In the UK, there are three species of worms that cause casts:

  • Common Worms (lumbricus terrestris)
  • Black-Headed Worms (aporrectodea longa)
  • Grey Worms (aporrectodea calignosa)

Unsurprisingly the Common Worm is the species most frequently found in the UK. This is the one which is more than likely to be causing those casts.

Worm casts are a lot more common at this time of the year (September-October). Worms will pop their heads up through the wet surface to eat, breathe, and reproduce. This is when the worm cast is left behind.

Something that goes hand in hand with worm casts is weeds. Weeds like the empty space. When worms expel the soil, they leave a gap between grass seeds. This gap is ideal for weeds.

Despite many in the industry finding worm casts a pain. There are actually quite a lot of benefits to having our wriggly friends around:

  • Worms help to increase soil aeration and therefore improve the soil structure. As worms eat the soil, they create little pockets of air. This improves the soil structure as it aids the movement of water, oxygen, carbon dioxide and nutrients underground.
  • Helpfully, worms eat lawn thatch as well as soil. They also consume dead roots and leftover grass clippings. All these things help with grass health.
  • Worm casts are incredibly nutrient-rich. This is because the digestive enzymes that are released through excretion concentrate the nutrients.

Having said those points. I can imagine that many of you reading this would still want to try and nullify worms as much as possible. Greenkeepers do not have the freedom to let their greens grow in order to mask the worm casts, so I have found some other methods which you might be able to use in order to deter the worms.

Get rid of the thatch- That's right, thatch is a vital source of food for worms. Therefore through the reduction of thatch, the worms will not be as attracted to the greens.

It could be chemistry- There are several worm suppressant products on the market. These products contain certain nutrients that worms absolutely hate. So it deters them from sticking around. Of course, the key is to deter and not kill off the worms. As mentioned, they do have valuable uses.

Reduce the water- Quite a tricky one for greenkeepers in the UK. The wet ground makes worms come up to the surface. They love the wet weather conditions.

Top dressing is key- Using a top dressing with a high concentration of sand will diminish the lawn's moisture and make the ground less appealing to worms - so it's a potential route to consider.

So worms- friends or foe? In conclusion, I suppose neither would be the answer here. They have beneficial effects on soil structure, and organic matter recycling and provide food sources for many species. However, they cause an eye sore and another job for turf care specialists all over the UK. I think this one goes down to a case by case situation.

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Wildlife & ecology