Plants Need Water Every Day

by Elmer Krehbiel, Master Gardener
July 9, 2004

In Central Texas, soil usually requires extra water after the weather becomes hot, dry, and windy.

Gardeners should understand the water requirements and the root systems of their plants. A good rule is to apply enough water in the morning for moisture to soak deeper than the roots of  plants.

After a new crop has been seeded or transplanted, a major responsibility for the gardener is to keep the soil moist. Water is the major component of plants, and it is required every day and night. The amount of water needed varies according to plant variety, the size root systems, the stage of plant maturity, and conditions including mulch and soil type, wind, humidity, and temperature.

Irrigation Methods

Drip irrigation is a highly efficient means of watering. With a drip irrigation, a soaker hose is placed on the surface on the surface or buried one foot deep. You can also use a root-watering rod or a  perforated jug or can buried between plants.

The traditional method of irrigation is a furrow between the rows of plants or around plants.

A less less desirable irrigation method is a sprinkler system that wets the plants, which usually makes them susceptible to leaf diseases.

If water is insufficient, leaves will slowly become yellow-tan, wilt, die, and fall off.

Many plants require about 25 percent water and 25 percent air in the soil. Since water replaces air in the soil, too much water in the soil may cause plant leaves will become brown from the tip, wilt, and die suddenly.

Water & Lawns

If you cannot insert a screwdriver into the soil, water with a soaker hose for 30 minutes, then move the hose. The next day, you should be able to push down the screwdriver 12 inches. This method helps grass develop deeper roots. If rainfall is inadequate and you have to resort to a sprinkler system, water applied slowly once a week will be better for grass than shallower applications three times a week. If rainfall is sufficient, turn off your sprinkler system until it is needed. Too much water causes shallow roots, weak plants, and more susceptible to some diseases.

Watering Trees

Trees have anchor roots near the trunk and feeder roots from half the distance to the drip-line, then much farther beyond it. Water should be applied around the feeder roots, not next to the trunk.

Water & Shrubs

The best landscape shrubs require less water and usually do not have serious disease or insect problems.

Deciduous shrub varieties are:

  • Possumhaw Holly
  • Albeseens Pomegranate
  • Chico Pomegranate
  • Nana Pomegranate
  • Pleniflora Pomegranate
  • Wonderful Pomegranate
  • Flowering Quince
  • Anthony Waterer Spiraea
  • Bridal Wreath Spiraea

Evergreen shrub varieties are:

  • Dwarf Abelia
  • Compacta Abelia
  • Edward Goucher Abelia
  • Wintergreen Barberry
  • Fruitlandi Elaeagnus
  • Berries Jubilee Holly
  • Blue Princess Holly
  • Dwarf Burford Holly
  • Burford Holly
  • Carissa Holly
  • China Girl Holly
  • Chinese Rotunda Holly
  • Chinese Horned Holly
  • Dazzler Holly
  • Fosters Holly
  • Mary Nell Holly
  • Nasa Holly
  • Needlepoint Holly
  • Savannah Holly
  • Nellie R. Stevens Holly
  • Dwarf Yaupon Holly
  • Weeping Yaupon Holly
  • Yaupon Holly, Southern Wax Myrtle
  • Nana Nandina
  • Harbor Nandina
  • San Gabriel Nandina
  • Moonbay Nandina
  • Gulfstream Nandina
  • Compacta Nandina
  • Heavenly Bamboo Nandina
  • Indian Princess Photinia
  • Chinese Photinia
  • Frasers Photinia

Water & Flowers

Flowers with low water requirements are:

  • African daisy
  • Apache plume
  • Artemisia
  • Babys Breath
  • Blackfoot daisy
  • Blanket flower
  • Brodiaea
  • Butterfly weed
  • Cockscomb
  • Dusty miller
  • Echeveria
  • False indigo
  • Gaura
  • Globe amaranth
  • Globe mallow
  • Hummingbird mint
  • Jerusalem sage
  • Lantana
  • Lavender
  • Mount Atlas daisy
  • Mullein, Orange justicia
  • Prickly poppy
  • Russian sage
  • Stonecrop
  • Sundrops
  • Thrift
  • Valerian
  • Verbena
  • Wine cups
  • Yarrow

Watering Vegetables

Fro vegetables, the critical periods of water needs are at the stages of germination, pollination, and fruit development. Most vegetable plants require about one inch of water per week. Plants in raised beds need more water than plants in a ground level garden, and those in containers will require the most. Again, rainwater is best for them, but you should compensate for a lack of precipitation by watering vegetables when necessary. Deep mulch will help retain moisture.

The vegetables with small, shallow roots are:

  • broccoli
  • Brussels sprouts
  • cabbage
  • cauliflower, celery
  • Chinese cabbage
  • corn, endive
  • garlic
  • leek
  • lettuce
  • onion
  • parsley
  • potato
  • spinach
  • strawberry

The vegetables with medium size and moderately deep roots are:

  • bush bean
  • pole bean
  • beet
  • carrot
  • chard
  • cucumber
  • eggplant
  • muskmelon
  • mustard, pea
  • pepper
  • rutabaga
  • summer squash
  • turnip

The vegetables with large-deep root system are:

  • artichoke
  • asparagus
  • lima bean
  • parsnip
  • pumpkin
  • winter squash
  • sweet potato
  • tomato
  • watermelon

Dr. Elmer Krehbiel is the former President of Keep Brazos Beautiful. See his column in The Eagle.