How Much Water to Use to Water Gardens

Plalnts have varying water requirements to fully saturate plant roots.

All plants require water for survival. Plants have different requirements. Some plants need constant moisture, others live in arid environments, subsisting on minimal amounts. Water applied to soil filtrates down through the root zone gradually. Each soil layer is filled to capacity before water works its way down to the next soil layer. The time required varies, dependent on the soil content. Coarse sand drains much faster than fine silt and clay.

Plant Roots Need Water

When determining how much water to apply to your garden, lawn, meadow or container plants, it is important to always supply enough water to reach the bottom of the plant's roots. Quick sprinkling is inadequate. When less water than is required for healthy plant growth is given, the water only permeates the upper soil layer, failing to reach the roots. The area below the moisture level will remain totally arid. Roots may dry out and die.

Evaporation

Flowers require water to reach their full potential.

When the water reaches the roots of the plant, it moves upward through the stem to the leaves, flowers and fruit. Plant leaves contain thousands of microscopic stomates (openings). Water vapor evaporates from the stomates in a process known as transpiration. If not replenished, the constant loss of moisture causes the plant to wilt and fail to grow.

Total Plant Water Requirement

Water trees deeply to saturate the roots.

The water requirement of a plant is the total moisture that evaporates plus the amount evaporated from the soil. Evaporation rates vary dependent on the temperature, length of the day, cloud cover, relative humidity, mulching and the size, number and type of plants living in a given area. For a healthy garden, monitor the needs of your plants closely.

Water Deeply

Water your plants until the root zone is thoroughly saturated, then allow to dry out slightly between watering. Using a garden sprinkler, sandy soil absorbs approximately 1/2 to 3 inches of water per hour, permeating to 12 inches deep into the soil. Clay, loam or silt may only absorb a fraction of that amount in the same time. During dry weather conditions, container plants may require watering several times per day.

References

• Colorado State University Extension: Ground Cover Plants; J.E. Klett, R.A. Cox; January 2009
• Maryland Cooperative Extension: Production of Hybrid Lilies as Cut Flowers
• Agri-Life Extension: Aggie Horticulture; Efficent Use Of Water; Jerry Parsons, et al.
• Washington State University: Gardening In Western Washington; Watering Home Gardens and Landscape Plants; George J. Pinyuh, et al.; June 1996

Resources

• Heritage Perennials: Succeeding With Hardy Ferns