Determining Plant Watering Priorities

Plants facing adverse conditions of extreme heat and wind has been the story over much of Wisconsin recently. Depending on where you live, rainfall may or may not have been adequate for yard and garden plantings. With significant summer weather left to go, it is important to prioritize which plantings to water as needs arise.

For example, many developing vegetable crops will be in critical growth stages related to drought stress in the coming weeks. Adequate water is needed to fill out ears of sweet corn and pods of beans and to ensure proper development of fruits such as tomatoes and peppers. When plants go under drought stress, harvest yield and quality suffer. All gardens that have been mulched, both vegetable and ornamental, thrive longer without rainfall or irrigation than if the soil surface is bare. Try to water early in the day, and if possible avoid getting foliage wet, especially on crops like tomatoes, to reduce disease potential.

Landscape flower beds, gardens, and groundcover plantings vary in water needs according to species, along with growing and site conditions. Make notes of high stress planting beds that may need replacement with more heat and drought tolerant species in the future. Regardless of the types of plants in them, hanging baskets and container plants are always top priority on watering lists, as they are subject to drying out extremely rapidly in heat and wind.

  Priority for trees and shrubs starts with newly established plants. Water the entire root zone area. Be careful, however, not to overwater, especially on clay soils, as roots sitting in excessively wet soil for prolonged periods can die even in dry weather. Check below the soil surface to adequately determine soil moisture levels. Established trees and shrubs also benefit from watering, especially if conditions become extremely dry, as important roots for nutrient and water uptake are shallow.

Browning lawns may be a very visible sign of heat and drought stress yet can tolerate adverse summer conditions quite well. Cool-season grasses will go dormant and resume active growth when conditions improve. If prolonged extremely dry conditions develop, applying 1/4 to ½ inch of water every 2 to 4 weeks will not make lawns green again, but should be enough to maintain crowns and roots so lawns survive and resume growing later. 

Hopefully, timely rains will fall throughout the balance of summer to avoid drought stress on plants. Even if your location in the state has been getting plenty of rain, it pays to evaluate all yard and garden plantings and develop watering priority plans to ensure plants make it through summer heat in good condition.