Strategies for Saving Drought-Plagued Lawns and Gardens

John W. Jett Horticulture Specialist WVU Extension Service Drought and hot, dry weather can have an adverse effect on garden and ornamental plants. When you find yourself in the middle of a drought, there are strategies to save or salvage home gardens and landscapes. Water is lost from plants and gardens in two ways. The first is by the evaporation of water from the soil surface. The evaporation rate increases under hot, dry and/or windy conditions. As the soil surface dries, more water from deep within the soil may be drawn to the soil surface, where it also evaporates. The second way water is removed from soil by plants in a process called transpiration. Most West Virginia lawns consists of cold-season grass species, which usually go dormant during the hot, dry weeks of summer and return to active growth in the fall. These lawns can be kept green and growing with proper watering, but in times of prolonged drought and limited water supplies the best approach is to let them remain dormant. When conditions improve and growth resumes, there are several recommendations that should be followed. Mowing height – Raise the mower deck to the highest setting. This promotes deeper rooting and maintains turf quality. Mowing frequency -- Mow less frequently. Mowing stresses the grass plants by increasing respiration and reducing root growth. Mower blade – Use a sharp blade. This produces a cleaner cut that heals more quickly and loses less water. Fertilization – Avoid nitrogen fertilizer that may stimulate excessive blade growth at the expense of root development. Overseeding – To improve lawn density, overseed in spring with the appropriate species. The best way to protect ornamental plants during periods of drought is by applying mulch. Research has shown that unmulched soil may lose twice as much water to evaporation as mulched soil. Three to 4 inches of good organic mulch such as shredded bark, rotted sawdust or compost will preserve soil moisture, prevent soil compaction, reduce soil temperature, and reduce water-robbing weed populations. When possible, apply water slowly to ornamental plants to achieve deep penetration that encourages deep rooting and drought tolerance. Newly planted trees and shrubs are more sensitive to dry conditions and will need frequent watering from planting time until they are well-rooted. Similar strategies can be used for vegetable and fruit crops. Most vegetables are shallow-rooted and will benefit from any practice that reduces water loss from either soil or plant. Here are some water conservation recommendations Collect roof water from downspouts to use for irrigation. Use drip or trickle – this method wets the soil slowly and deeply. Up to 60% of irrigation water can be saved using drip versus overhead watering. A perforated sprinkler hose placed with the holes down makes a good drip system. Be sure water penetrates soil. Very dry soil often is hard to wet. Add 1 teaspoon household dish detergent as a wetting agent per 5 gallons of water. Irrigate in early morning when humidity is high. There will be less evaporation. Use mulches and/or row cover around and over plants to reduce water loss by evaporation and transpiration. Control weeds. Weeds compete with crops for soil moisture and decrease yields. Most vegetable crops are sensitive to drought three to four weeks before and during harvest. Listed below are periods of plant growth when an adequate supply of water is critical for high-quality vegetable production. If possible, irrigate during these critical periods. Crop Critical Period Asparagus Brush Beans: lima & snap Pollination and pod development Flowering and pod enlargement Broccoli, Cabbage, Cauliflower, and Lettuce Head development Carrots Root enlargement Corn Silking and tasseling, ear development Cucumbers, Eggplant, Peppers, and Melons Flowering and fruit development Potatoes, radishes, and turnips Tuber set and enlargement Tomatoes Early flowering, fruit set, and enlargement If growing conditions improve, there are several vegetables that can be grown as fall crops. Consult the West Virginia University Extension Service Garden Calendar for seeding and planting dates. And remember! All plants are more susceptible to invasion by insects and diseases when under stress. Monitor plants closely for pests and take appropriate control measures.