I was asked this question; My compost heap is overrun by ants – can I use the compost to earth up potatoes and for other uses?
The simple answer is yes, compost infested with ants is fine for earthing up potatoes and other outdoor uses.
Ants Nest in the Compost Heap
Ants will often build their nests in a cool compost heap. It’s fairly ideal for them, warm and easy to tunnel in. Lots of other insects about for them to eat as well. Hot compost heaps where the temperature goes up to 60ºC or higher will kill any ants.
It can be a bit daunting when you disturb a large nest of ants in the compost heap and thousands of them mill about but it’s not really a problem.
Ants in the Garden
Ants can be a problem in the garden, although not a major problem. They don’t directly eat our crops and it’s arguable they actually benefit gardeners by eating pests.
Where ants are a problem is that the black ants often farm aphids, protecting them from predators. The ants benefit from the honeydew that the aphids produce so they encourage them. The damage to the plants is done by the aphids sucking the sap but the ants make it worse.
The Ant Colony
In the ant colony there will be basically worker ants and a queen. The queen lays the eggs and produces pheromones which are the chemical signals that co-ordinate and bind the colony together. The workers do everything else.
Once you dig up the compost heap and spread it around, the worker ants will be disorganised and the eggs will die for lack of attention. Although the worker ants can live for 2 or 3 years, the chances are that they’ll all be gone in a matter of days, picked off by predators as they go wandering off in search of home and instructions.
The queen ant typically lives for 10 years but without her worker ants to feed and support her she’s unlikely to last more than a day or two. So you needn’t worry that you are establishing a new ant colony.
Red Ants in the Compost Heap
So, don’t worry about the ants in the compost heap unless they are red ants in which case you need to be cautious handling the compost.
Red ants bite or sting and this can be a real problem. A hot summer’s day and I was dressed in shorts. Kneeling to weed a raised bed I didn’t notice the ants swarming up my legs and into my shorts. Luckily I had shed to run into or I could have been arrested for indecent exposure!
Note: this article refers to ants in the UK. Readers outside the UK should be aware their ants may be more aggressive like fire-ants in the USA.