Compost Thermometers – Quick Tips on Using Compost Thermometers

Compost thermometers. What are the advantages to using a compost thermometer and how do you use one?

When a compost pile is the most active, the interior of the compost pile will heat up significantly. If you’ve had a good compost pile running before, it’s not uncommon on a crisp fall day to lift the top layer of a pile up and see steam rise from the pile from the gray decomposing mass of the active part of the pile. The internal temperature of an active pile can reach 110 to 140 degrees F after a few days, and this is when the pile is most active and productive.

But if the pile has too much green matter it can get even hotter, but this will cause it to leach nutrients, and often start to smell. So it’s good to keep your pile it this sweet spot of activity, and you will reap finished compost much faster. With a compost thermometer you can gauge whether you’ve gotten a good mix of materials to get the pile started, and also when it’s cooled off you know it’s time to turn the pile to get more fresh material into the center of the pile to get it to heat back up again.

Compost Thermometer $24.95 Store: Gardener’s Supply Company Compost Thermometer – TRI-101-CT $39.99 Store: Hayneedle

If you are looking for a compost thermometer here’s a couple of things to keep in mind.

Length – Depends on the size of your compost pile or bin, but you want to be able to reach the middle of the pile. Size’s range from 12 to 30 inches on most compost thermometers, a good size for the typical home garden would be a 20 inch model.

Speed – How fast can you get a reading? Some older models use a bimetalic sensor which can take a couple of minutes to give a stable reading. Electronic meters give a much faster reading.

Temperature range – Get one that will do up to around 200 degrees F.