Extension News

Ask the ISU Extension Garden Experts: Fish, Lichens and Compost

Note to media editors: Got gardening questions? Call the Hortline at (515) 294-3108, Monday-Friday from 10 a.m. to noon and 1 to 4:30 p.m., or e-mail us at hortline@iastate.edu. For more gardening information, visit us at Yard and Garden Online, http://www.yardandgarden.extension.iastate.edu

10/15/2009

How do I overwinter the fish in my water garden?

In the Midwest, you will need to install an air pump or heater (which can be expensive to operate), leave the fish in the pond, or remove the fish. If the fish are left in a pond without a pump or heater, the water must be at least four feet deep so the pond will not completely freeze to the bottom and kill the fish. If you use an air pump or heater, check it occasionally to make sure it is functioning properly. If the pond is shallow, bring the fish indoors before winter and keep them in a tank suited to the size and number of fish. These tanks are often placed in unheated garages. Remember that if you have a large pond, with lots of fish, you will need a large aquarium to maintain them during the winter.

There are gray-green patches on the trunk of my tree. What are they? Are they harming the tree?

The gray-green patches are probably lichens. Lichens are unusual organisms. They consist of two unrelated organisms, an alga and a fungus. These two components exist together and behave as a single organism. The agla provides food via photosynthesis. The fungus obtains water and minerals for itself and the alga.

Lichens are common on trees because the bark provides a suitable place to gather sunlight and grow. They grow especially well on dead branches because they receive more sunlight. In addition to growing on the trunks and branches of trees, lichens can be found on exposed soil surfaces, rocks, wooden fence posts, shingles, gravestones, stone walls and other sunny surfaces. Lichens may be flat, leafy, or branched and hair-like. The lichens on trees are often gray-green. Other species may be orange, yellow, slate blue or black.

Lichens are fascinating, unique organisms. They do not harm trees.

Will a compost pile produce objectionable odors?

A properly prepared and maintained compost pile will generate little, if any, objectionable odors. Unpleasant odors may arise if the compost pile contains excessive amounts of wet plant materials (such as fruit or grass clippings), is kept too wet or is not turned on a regular basis. When constructing the compost pile, mix wet plant materials with dry plant debris. Keep the compost pile moist, but not wet. The composting material should feel damp like a wrung-out sponge. Turn the compost pile at least once or twice a month. Odors are emitted by poorly prepared or maintained compost piles.

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Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Del Marks, Extension Communications and External Relations, (515) 294-9807, delmarks@iastate.edu