Climate, Temperature & Worm Composting

Jerry Lambeth Asks:

“How do you keep worms in the winter, I would like to raise some red worms.” And…

Jeff Poole Asks:

“I live in a very hot climate and struggle to keep worms alive during summer. The bin is in the shade and I have covered the bin with carpet which I wet but still lose worms on a hot day.” And…

Amanda Johnston Asks:

“I have had worms for ten years. This was a long hot summer and every one died – first time ever. Any tips to avoid it happening again? I did add more water – to no avail. Plastic got too hot even though under trees.”

All three asked very similar questions here, and so I have grouped them together.

The topic here is temperature. There are two problems and are two extremes that are experienced depending on your geographical location.

Up in Europe or Canada it can get quite cold and the fear is that when it snows, it may freeze the worms to death.

In countries with a more tropical climate, the heat can bake the worms to death. As it is coming to summer, many of you will be interested to know what you can do to prevent worms dying from the heat wave!

So what if you are in the cold?

First of all you will need the right worms. As I had mentioned in the previous questions worms such as Eisenia Foetidas and Dendrobanas are more suited for colder climates (although they are both quite versatile). These are also the more popular choice for composting.

Depending what type of system you have there are different things you can do.

For a home-sized wormery you can simply bring the bin indoors such as the garage and put a large thick cloth or carpet to cover over it and insulate it.

Worms work slower in the winter, and will consume less oxygen so don’t worry too much about not having enough air as long as you open the bin once every 2 days. Make sure the bin doesn’t freeze over then the worms should be fine.

If you have a large worm bed which you can’t move easily there are a few ways you can keep your worms warm.

Piling a thick layer of straw or leaf on top can keep the worms underneath warm. If the area you are in is a relatively constant cold temperature, then instead of worm beds, you can dig a ‘worm trench’. The earth is a good insulator from the surrounding cold, and having your worms underneath ground level can keep your worms warmer year round.

If you experience extreme hot climates, then there are different things you can do too.

For Jeff, it seems you live in an area where hot climate is the norm.

In this case you may have to consider a different breed of worms such as the Eudrilus Eugeniae (AKA African Night crawler) or the Perionyx Excavatus (AKA blue worm), which are more suited for constant warm temperatures.

These can not tolerate the cold but should not be a problem for you.

For Amanda it is a trickier one, because you experienced a one off heat wave.

You both are doing well in re-wetting the beds to prevent them from drying.

Don’t use carpet which will insulate it. Instead use a thin plastic white sheet to cover the beds to deflect any sunlight. There are also many items you can use in a household store which is designed to keep the house cool during summer such as heat reflecting films and aluminum films. These products can also be used the same to keep your beds / wormery cool.

If it is still bad, you will need to perforate holes in the plastic sheets to allow airflow and for the evaporation of water from the beds. This will allow water to bring heat away with it through evaporation instead of having heat trapped in with the worms. The problem with this is of course the constant need of re-watering to keep your bed wet.

If possible do keep them in the shade (indoors even better). If not, and you are getting desperate, you may have to separate some of the worms into buckets and take them indoors temporarily from the scorching sun (it may be a hassle, but better than having dead worms!)

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