Ask the master gardeners

Q: Someone told me that all this rain we are having is not good for cucumbers. What problems should I look for?

A: Cucumbers are a staple in virtually every well-rounded home vegetable garden. Although cucumbers will grow in any good garden soil in the pH range of 6.0 to 7.0 (typical for most vegetables), they hate wet feet so it’s important to have good drainage.

Native to the tropics, cucumbers need at least 8 hours of sunlight a day and warm, humid conditions to thrive. Plants subjected to temperatures below 60 degrees will grow less robustly and be more susceptible to disease. Because of this, it is important not to plant them too early, ideally three to four weeks after the last frost. In our area, this would mean setting seedlings out around the first two weeks of June.

There are several diseases that are common to cucumbers during damp weather including powdery mildew (leaves covered with a white powder), botrytis (gray mold), downy mildew (yellow or purple spots on leaves, which then die). Powdery mildew especially is brought on by warm, dry days and damp, cold nights: exactly the conditions we frequently see in early to late spring. Delaying planting until June will help avoid these conditions.

To further avoid disease during the growing season, use a mulch that will prevent water from splattering up from the ground during a rain or overhead watering. Consider using a soaker hose to avoid splatter and avoid watering in the evening when moisture is likely to remain on the leaves overnight. If diseased leaves do appear, remove them promptly and dispose of them away from other plants.

Composting diseased leaves can spread the problem for years to come. Avoid spreading spores between diseased and unaffected plants by cleaning contaminated pruning shears, hands and clothing.

Keep in mind that cucumbers, melons, squash and pumpkins all are susceptible to the same set of diseases. Crop rotation can prevent the spread of disease from year to year.

Growing vegetables under ideal conditions ensures the healthiest plants possible, which is the best first line of defense against diseases and pests. By planting at the appropriate time and using sound horticultural practices, many of the problems associated with disease can be eliminated.
Kim Lindner, master gardener, Cornell Cooperative Extension of Westchester