Water Conservation in the Vegetable Garden

Proper watering is an important part of maintaining a productive and healthy vegetable garden. In this week’s “Ask a Master Gardener”, Barb Danielewski reviews the “how to” of watering your garden and of water conservation.

To plan a drought resistant garden that will thrive despite inconsistent rainfall and that requires little additional watering, start with healthy soil, deep root systems, and passive rainwater harvest. 

Building Healthy Soil

Healthy soil is rich in microorganisms – a web of bacteria, fungi, nematodes and insects, all interacting and enriching the soil with nutrients.  In addition to these living components, soil also contains minerals, water and air. Water and air are constantly exchanged through spaces in the soil. To avoid compacted soils with little air space, reduce foot traffic in the garden, marking paths where you plan to walk. The earth can be aerated by gently using a shovel or pitchfork to loosen the soil. Tilling or double digging is not needed. 

Image Credit: Gardenerspath.com

Adding organic matter to your garden throughout the growing season will build and maintain healthy soil and will help retain water. It acts as a sponge, first soaking up water and then slowly releasing it. Barb suggests building “pockets” of organic material around your trees and plants.

Mulching is a great way to retain moisture, reducing evaporation at the soil surface. Various materials can be used – grass clippings, shredded brown leaves or wood chips will all do the trick. Do not place mulch directly against tree trunks. Inorganic stone mulches are also useful in some situations, reducing weeds and increasing heat. 

Support Deep Root Systems

The development of deep root systems reduces the need to water frequently. When the surface of the soil is dry, plants find the moisture they need at lower levels.  This is accomplished by watering deeply about once a week (depending on rainfall) since shallow, inadequate watering causes roots to seek water at the surface instead of penetrating deep into the earth.

Image Credit: Gardeningblog.net

Water Conservation

Do you use a rain barrel? Many Kingston gardeners have embraced the use of a rain barrel (or two), which brings a number of benefits to the garden and to our community. As opposed to treated municipal water supplies, rain water is freely available, contains no added chemicals and is always at ambient temperature, reducing the shock of cold water to tender plants.

Image Credit: Utilities Kingston

Rain Gardens

You could also consider building a low maintenance rain garden. This type of garden directs water runoff from roofs, downspouts and driveways to a prepared bed, usually on sloped area. It temporarily holds and filters runoff. Barb suggests digging a bowl shaped pit, 12-18 inches deep and filling it with a soil blend of 30% organic matter, 50% sand and 20% top soil. The garden should be 3 metres or more from building foundations.  Utilities Kingston has great resources on native plants suitable for a rain garden.

Watering Tips and Tricks

  • Direct water to the roots of the plant, not the leaves, to reduce risk of disease
  • Utilize a drip irrigation system
  • Weeds compete with vegetable plants for water (and nutrients), so keep up with weeding 
  • Water early in the morning, 1-2 times per week (depending on rainfall) 
  • Water after a light rain to ensure a deep soaking 

When Does My Garden Need Water?

Each type of plant has different watering needs, so become familiar with the requirements of the crops you grow. Then, observe your garden. Are the plant leaves wilted? Are leaf tips brown and dry? Is the soil surface cracked and hard? Try checking the soil with a moisture meter, or dig down to see if there is moist soil below the surface that can be formed into a ball.

In Barb’s garden she watches what the plants are telling her and lets the rain do most of the work!


Utilities Kingston Water Conservation Garden

Note that rain barrels, usually available at cost from Utilities Kingston, are sold out for 2021