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How Hot Is Your Compost Pile?

Heat and steam mean the microbes are working

The temperature in the middle of my compost pile ranges from 90 to 120 degrees. I measure using a compost thermometer with a 14-inch stem. The height of the pile has been shrinking rapidly, with the center sinking faster than the edges. Temperature and shrinkage tell me that the microbes are feasting, changing those leaves, weeds and grass clippings into compost.
    Heat is a by-product of composting, as is carbon dioxide and water vapor. Dig into your compost pile on a cold day and you should see steam rising and feel heat. These signs mean that the microbes are digesting the sugars, starches and cellulose and converting them to carbon dioxide. The decomposition of the leaves, grass clippings, weeds, etc., releases nutrients that become part of the compost’s slow-release fertilizer.
    If your compost pile is not shrinking and its temperature is similar to that of the surrounding air, that’s evidence that the pile is not composting. The leaves could be too dry. Or the pile could be inert because you failed to add either soil or active compost to leaves when building it last fall. To get it working, you need to add nitrogen in the form of commercial fertilizer, grass clippings or animal manure to balance the carbon to nitrogen ratio. Active composting requires that sufficient nitrogen, organic or inorganic, be included with the leaves.

Are Your Rose Canes Whipping in the Wind?

If your roses are more than two feet tall, prune the canes back to about 18 inches from the ground. Fall pruning soon after they have finished flowering is best, but it’s still not too late. Off-season pruning prevents the tops of the plants from being whipped by winter winds. This is especially important for grafted roses. Pruning Knockout roses — which are grown from rooted cuttings — back to 18 inches prevents their lower branches from splitting.

Ask Dr. Gouin your questions at [email protected]. All questions will appear in Bay Weekly. Please include your name and address.

    At this time of year, the most effective method of wetting down a compost pile, especially one that is mostly dry leaves, is to dump dirty, greasy dishwater over them. If you did not add compost or soil to the pile when building it, dissolve a cup of high-nitrogen lawn fertilizer in the dishwater before dumping it. A daily dose of dishwater in conjunction with a weekly treatment of fertilizer will kick-start the composting. If you wish to hasten the process, turn the pile thoroughly in early to mid February.