Sunday, 16 September 2018

White worms in the compost

I had a question from Terese, in the small hours of this morning: she asked about small white worms which had found their way, uninvited, into her compost heap.

The questions were, are they baby brandlings, and will they do the compost any harm.

Firstly, no - they are not baby brandlings. Brandlings are red from the word go, they start off as tiny red things and then become larger red things.

The small skinny white worms are Pot worm, or potworms, proper name Enchytraeidae. I have no idea how that is pronounced - I'd go for Enky-try-eye-day, I think. They are a group of worms who like things really, really wet, and with a very low pH, ie an acidic environment.

A good compost heap will have a more-or-less neutral pH, and will be good and moist but not soggy. So you can see that if the potworms move in, the brandlings have probably already moved out.

The good news, and the answer to the second question, is that the potworms do the same job as the brandlings - they will scoff the organic matter, then poo it out, thus creating compost. The “bad” news, if you can call it that, is that the compost they produce is going to be rather more acidic than neutral, which might not suit your plants.

Although, as you are apparently adding a lot of low-pH material to your compost, your garden is probably quite a low-pH one anyway!

So if your compost contains lots of tiny white, semi-translucent worms, you now know that they are potworms, and it's an indication that your compost heap is a bit too wet, and a bit too low in pH.

If you want the brandlings back, it's quite simple - you need to change the conditions of your compost heap, by drying it out a little, and raising the pH.

To dry out the compost, you can add dry, crunchy material such as flower stems, dried-out strimmed long grass, or shredded paper, stirring them well in: and you can cover the heap from rain and dew for a few days, taking the cover off when the sun is out.

Then, to raise the pH, the standard remedies include adding wood ash and stirring it well in - which will also help with the soggyness problem, by aerating the material - or finely crushed eggshells.

The final suggestion - and this is not my own, this one comes from the internet, so no guarantees! - is to soak a slice of break in milk and plop it down on top of the heap. After a few days, it will apparently be colonised by the potworms, and you can then remove it and either dispose of it, or bury it in the garden somewhere. This will drastically reduce their population so, along with changing the conditions of the heap, this should break their cycle of dominance.

So now you know! Red worms, white worms, all worms are good, and they also act as an indicator to tell us something about the composition of our compost.


  1. Only red worms here, but I will be watching out for those white ones - and using the compost on my blueberry bushes if they appear! Funnily enough I am wrestling with a plan to transfer "excess" brandling worms from home to the school compost bins. I figure it would give the bins a kick start. I might give that bread and milk technique a go. So far I have noticed that the one thing they are most attracted to is strips of coia (from a discarded doormat). Once populated these can be lifted out and put in a bucket for transport. Of course I keep burying the strips with each addition of kitchen/garden waste so a tub of bread and milk which can be lifted out might be a better idea.

  2. Sounds like a plan, Mel! I have no idea if the bread-and-milk idea works for brandlings, but it's worth a try.

    And even though brandlings do miraculously appear in new compost pens, yes, I have in the past taken a double handful of compost and worms from an old heap in order to get a new one off to a flying start.

    You don't need to do anything fancy, though: just move aside the top layer of your heap, until you can see an area with lots of brandlings in it, then scoop out a dollop of it in a bucket, or a bag with no holes. They breed like magic!

  3. Thank you Rachel!! :) My plants don't actually thrive in an acidic environment - I haven't placed any compost on them yet! This was really helpful!

    I add to my compost fruit peels and vegetable waste, with the only browns being cardboard and dried leaves. If I continue to add more of these browns is it possible for the pH to increase back to neutral levels?

    I'm a bit hesitant to try the bread and milk idea though - I was told never to add any!

    Thank you so much!


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