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Hot weather and your worm bin

Posted 5/24/2016

Compost worms and castings

Compost worms and castings

As summer approaches, we are preparing for the times of amazing heat in the Mojave Desert. We may complain about it, but this smallest and driest North American desert is our home. We have the means to survive temperature extremes, such as fresh water and air conditioning. Desert gardeners even make sure that their plants get shade and extra irrigation, when necessary.

It is also a time to protect the worms in our compost bins. If you have not yet discovered the great work that compost worms do, you should explore it. Their demands are small, and the rewards are large. Their castings are a fabulous source of plant nutrition.

Heat is good for them, up to a point. Compost worms thrive, eating their own weight daily when temperatures are somewhere between cool and warm, around 60°F to 90°F. As long as they remain moist, these “red wigglers” are as happy as worms can be. Worms breathe through their skin; if it becomes dry, they will die. Fortunately, if conditions are not too severe, eggs may survive and grow when the bin is rehydrated.

These are not night crawlers or bait worms. Compost worms (Eisenia foetida) do not live in soil; instead, they flourish in decaying organic matter. They need the rich waste that we otherwise discard. In order to remain healthy, they should be living in a container that has access to air. A tote box with ΒΌ” holes drilled into the sides makes a perfectly acceptable worm bin.

Because they are quick to decompose it, I use compost worms to digest household food waste, and a standard compost bin for garden debris like leaves and pruned branches. This keeps pest problems down. Another way to limit pests is to freeze food waste before placing it in the bin. Freezing kills most insect eggs that could be present, and since water expands when it freezes, it begins the breakdown process before the worms start eating. Of course, it is a good idea to thaw the “feedstock” so as not to shock them.

From fall through spring, worm bins can remain outdoors, although this may be risky. Those winter nights when temperatures drop into the 30s can kill them, so they do need protection. In general, a protected place like a garage is a better place to store them through most of the year. Summer, however, is a much greater threat, and even the heat in a garage can be excessive.

The contents of a worm bin can become well above 100°F, and do not necessarily cool as quickly as the air outside. This means that the worms have little chance of escaping a fatal situation. Many of our homes have a second bathroom, often with a bathtub or shower stall. Are you using it? This can be an ideal spot for a bin through the summer. Unless they are very understanding, however, you probably want to take the bin out of the shower if you are expecting overnight guests.

Email or call Angela O’Callaghan, Social Horticulture Specialist for University of Nevada Cooperative Extension, at 702-257-5581.

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