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Watering New Plantings

New garden that has been watered prior to being mulched.

New plantings need water!

The roots of newly planted trees and shrubs must be kept steadily moist, but not soggy, as the developing roots establish in new soil. At planting, water thoroughly to soak the roots and to settle the new soil around the root mass.

The amount of supplemental water needed each week during the first season after planting depends on rainfall, temperature, wind, and soil conditions. If less than 1” of rain has fallen in 5 ‐7 days, the plants must be watered or they may not survive.

One of the most critical times for supplementing rainfall is in the fall months. Maintain weekly watering , as needed, until the ground freezes.

How Much Water?

In general, ten gallons of water applied twice a week will wet a 20” – 24” root ball and provide the equivalent of 1” of rainfall.

Measure the amount of water you apply by filling a container of known volume with water running slowly from a hose with no nozzle. For instance, if it takes 5 minutes for the water to fill a 2‐gallon watering can, you know that it will take 25 minutes to apply 10 gallons of water with the hose.

Run the water at a consistent rate each time. Set a kitchen timer to tell you when stop!

Keep the root mass moist. It will dry out more quickly than the surrounding back‐filled soil. Monitor the soil moisture to a depth of 12”by probing gently with a spade. Test for moisture with your fingers.

Water Wisdom

  • Water slowly, avoid runoff. 
  • Make sure water penetrates deeply to establish healthy roots. 
  • Avoid frequent, light sprinkling. 
  • Measure rate of flow from your hose, or use a can or bucket of known volume. 
  • Account for rainfall and weather conditions. 
  • Sandy, dry soils need more water. 
  • Check soil moisture by physical inspection. 
  • Too much water can kill plants; soil should never be soggy. Roots need air as well as water. 

Flower + Vegetable Gardens

Water flower and vegetable transplants with 1½ quarts of water and larger perennials with 3 quarts of water at planting. Use less water if the soil is heavy and/or poorly drained. Garden plants also require 1” of rain, or supplemental water every 5 – 7 days.


Keep newly seeded grass areas consistently moist until an even stand of seedling growth has established. Avoid water run‐off. A thin layer of straw over the planting will help shade emerging seedlings and retain moisture. Decrease the amount of water gradually to encourage deeper rooting. Thereafter, 1” of rain or supplemental water each week is optimal.

Mulch conserves water

Mulch new perennials, shrubs, trees at planting time to conserve moisture, and to suppress grass and weeds. This encourages fine root development and healthy growth.

Weather promises to become more erratic as climate changes. Expect heavier rain events and more frequent prolonged hot, dry spells. Water with care.