Cucumber plants are a vining vegetable commonly grown by home gardeners in pots and in garden beds. Cucumber leaves can curl for a variety of reasons. In some cases, the curling leaves are not an indication of poor health or of poor growing conditions. However, in other cases, curling leaves are one of the earliest signs of stress on the cucumber plant. Look for other indicators to properly diagnose the reason for the curling leaves.
After a cucumber harvest, the leaves of the cucumber plant will curl temporarily. This is a natural reaction on the part of the plant, as it is a defense mechanism. When the leaves of the cucumber plant curl, it is conserving energy and nutrients from leaf production and sustenance towards producing more fruit to replace the harvested cucumber. After one or two days, the leaves of the cucumber plant will uncurl. When harvesting cucumbers, snip off the cucumber from the plant using a pair of garden scissors to reduce the amount of stress and trauma for the plant.
Cucumbers are a vining vegetable, and may sometimes need to be trained or pruned in order for optimal growing conditions. Cucumbers can be trained to trellises or other support systems, and are sometimes pruned so that they do not become too unwieldy. Pruned cucumber plants will have temporarily curled leaves as a way of conserving energy and as a reaction to the shock of being pruned. Over pruning or pruning too frequently damages a cucumber plant. Prune only when necessary, and no more than once every two weeks.
Poor Soil Nutrition
Poor soil nutrition can cause the leaves of the cucumber plant to curl as an indication it is under stress. Check the soil nutrition levels of your garden by using a soil test kit. The kit can be purchased at a garden supply center. Add manure and compost to your garden soil before planting cucumber plants to ensure healthy soil for your cucumbers before they begin setting fruit.
Under watering cucumber plants will cause the leaves of the plant to curl, wilt and turn yellow. Test the soil moisture levels by feeling the soil one inch below the surface. If the soil is dry, dusty or hard to the touch, then your cucumber plant is being under watered. Water your cucumber plant daily, giving it more water on days that are predicted to be especially warm. Mulch your cucumber plants to help maintain an even level of soil moisture.