It has been plenty warm this summer. Today’s column has tips to keep plants hydrated while at the same time being mindful of the water bill. Plants need strategic watering strategies during days when temperatures soar over 100 degrees Fahrenheit.
• Water early in the day. When watering, consider the plants and the soil. Water lost from plants is transpiration and water lost from soil is evaporation, together called evapotranspiration. Avoid watering in the heat of the day as evapotranspiration increases as temperatures increase and sunlight is high.
• Apply water directly to soil using a drip system or water hose rather than sprinkling the foliage. There are two disadvantages to watering with a sprinkler: water hits the foliage and if it persists into the evening, will exacerbate diseases; secondly, as water sails through the air water droplets evaporate, which lessens the amount roots receive.
• Check plants early in the day. Plants in the hot afternoon sun will often be wilted. Wilted leaves are normal and not a cause for concern unless leaves wilt early in the day. Plant tissues are hydrated as roots absorb water during the night hours. Wilting leaves in the afternoon means that water lost by transpiration has exceeded the rate of water movement from soil into the roots and into plant tissues. With sufficient water in the soil leaf moisture will rehydrate and recover by the next day.
• The general rule in watering is one inch per week, but the amount of water a plant needs varies with the size of the plant, larger plants need more water than smaller plants; dark green leaves heat up faster than lighter colored leaves and will require more water; large leaves have more surface area for losing water and will need more water than smaller leaves and leaves that are deeply lobed; plants grown in full sun experience high evapotranspiration and need more water than plants grown in the shade. Application of water varies with delivery system: drip systems deliver frequent, small amounts; if no drip system, apply heavier amounts several times a week.
• Look at your soil. Water is quickly drained in sandy soils and the other extreme is with clay soils that are difficult to hydrate. Organic matter helps with both soils. Organic matter increases water retention in sandy soils and loosens the soil particles in clay soils, facilitating water movement.
Ellen Peffley Harp, a retired professor of horticulture at Texas Tech University, writes about gardening for several Texas newspapers.
