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Water loss can cause leaf browning

Mary Small, Special to The Rocky

Published April 13, 2007 at midnight

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Question: The leaves of my Oregon grape holly are brown around the edges. Is this some kind of disease?

Answer: The problem sounds like winter injury. During the winter months, evergreens continue to transpire or lose moisture to the surrounding environment.

Warm temperatures, sunlight and wind can all increase the amount of transpiration. Plants must replace the moisture lost through this process to stay healthy.

If the soil is frozen that will be impossible. If water loss is rapid, the plant cannot physically keep up with it. If plant roots are functioning poorly or are damaged as a result of soil compaction, excessive or insufficient water or excavation activities, they will not be able to keep up with the loss, either. The result is the brown leaf edges that you describe.

New growth should cover the damaged areas and plants will look more attractive later in the season.

Q: What makes lettuce bitter?

A: Any factor that stresses the plants can result in bitter-tasting leaves. With lettuce, it is usually excessive heat or insufficient water. Crowded plants and advancing age could also make lettuce taste bitter.

Q: Carrots seem to have difficulty sprouting in my garden. Do you have any suggestions to improve this?

A: Carrot seedlings are weak and have a hard time penetrating crusty soils. After planting, cover the row with a piece of burlap or a board. These help keep the soil from crusting over, resulting in better sprouting. Check the seeded area regularly.

Once the plants sprout, remove the covering. Instead of a covering, some gardeners plant radishes in the same row with the carrots, as those seedlings are better able to break the surface crust. Radishes grow quickly, and when harvested, make room for the developing carrots.

Mary Small is a Colorado State University Cooperative Extension agent in Jefferson County. www.planttalk.org