Metro-East Living

Why lemons aren’t turning yellow

Q: I have a lemon tree with two huge lemons on it, but they are not turning yellow. What am I doing wrong?

K. F. of Belleville

A: You are not doing anything wrong. Lemons belong to the citrus family and are not like apples, peaches, plums or pears. They are tropical. You just have to be patient with them. They may look more like grapefruits when they are grown indoors.

Citrus fruits form the necessary sugars at the end of development, not slowly building up over time. Be ready to help the plant support the fruit as it develops a large size.

If you are still fertilizing the lemon tree, stop applying the fertilizer now and the lemons will ripen sooner because too much nitrogen can delay the ripening process.

Q: In order to reduce weeds growing in and around my flowering areas, I am considering placing old roofing shingles around flowers and shrubs and putting mulch on top. Would the shingles be harmful to the plants now and in the future? Also, our turnips did not develop and the tops are turning brown. Why did this happen?

V. H. of Belleville

A: The jury is out on the use of roofing shingles as mulch. There has not been a true scientific investigation that examines the complete effects of using shingles as a mulch, its effects on how plants respond and any detrimental effects on plants. Shingles work well as a base for walkways to prevent weeds. But when used around plants, researchers are looking into it. They want to learn if plants can survive near places where piles of old shingles have been abandoned. Weeds seem to adapt very well, but nothing has been studied for wanted plants.

I would not suggest using them around edible plants because we don’t know which plants absorb what chemicals from shingles. I would certainly not recommend tearing the shingles into smaller particles because this would be trouble to try and remove these smaller parts of shingles if the mulching did not work. There will be problems with the heating of soil which may damage roots and injure flowering plants.

An interesting side note is at the end of World War II, there was a trial for war crimes because of an aerial dumping of ground shingles on the soil of German-occupied France. I could not find out how the verdict turned out and what happened to the soil.

Your turnip problems may be caused by planting the seeds too early. They should not be planted before Aug. 15 because the first fall frost happens around Oct. 20. Don’t just plant one variety but several, if possible.

Also, do not plant turnips where cabbage has been grown previously in the year because cabbage maggots will eat the roots. Air temperatures above 80 degrees also will limit the growth and cause browning of the leaves. If the soil dries out too much, you will need to water to help the plant develop.

When the cool evening temperatures begin, the sugar content builds up in the turnips and improves the flavor.

If you notice wilting, dig up some of the turnip plants to inspect for wireworms and clubroot fungus because this could also be a problem. You can check for wireworms by placing a piece of carrot or potato on a barbecue skewer and inserting it underground 2 inches to see if any eating has occurred. Check about two times per week.

Clubroot fungus is found in soil that has been kept too wet. You will find swollen areas on the roots. Forget about raising turnips in ground where the fungus is — spores will last about 20 years in the soil.

Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Editor Maureen Houston, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to mhouston@bnd.com.

Do it now:

Holly cuttings can be started now as well as cuttings of lilac, privet, and mock-orange.

  Comments