The annual garden is in and I’ve now moved into maintenance mode. In addition to daily greens and herbs from the garden, I’m now harvesting peas, my rhubarb is still going, I just picked the last of my garlic scapes, and the strawberries are coming on! Cherries, gooseberries, raspberries and currants are ripening in my food forest and the rest of the veggie garden is chugging away. It’s always such a nice feeling to get out of the scramble of planting season and into the routine of regular maintenance.
Among other tasks, regular maintenance means watering. Because we’re moving out of our wetter months and into crispy and dry July, I though this would be a good opportunity to talk a little bit about water conservation strategies and watering in the garden.
Water is a precious resource and if you’re a gardener in the Rocky Mountain West, you understand that more than most. The first and easiest step is always water conservation.
For those who have participated in my workshops this season, you may have heard me talk about the City of Bozeman’s Water Conservation Initiative. As Bozeman grows, the city has identified water conservation as the single largest source of water for Bozeman’s future. Even if you don’t live in Bozeman, there is a Planting & Outdoor Watering Guide which gives you great suggestions in terms of drought tolerant perennial plants for both sun and shade. Many of these plants are edible, medicinal, attract beneficial insects and create wildlife habitat. What’s more is that you can get rebates from the city if you buy these plants or install rain sensors or drip irrigation systems. So with a little planning and design, you can install an ecological garden for free or with very little investment!
Of course, not everything we would like to grow as gardeners, especially when it comes to fresh fruits and vegetables, is drought tolerant. In spite of this, there are still a variety of ways to keep water use to a minimum while maximizing our yields.
To be water-wise in your garden, watering by hand if you have a small garden or installing a drip irrigation system will allow for the most conservative use of water. Remember to water less frequently and more deeply, preferably in the morning, rather than daily for short periods of time. If you water your garden daily, the plant roots stay at the surface. If you water less frequently, the plant roots will grow down, searching for water, creating a more robust root system and a healthier plant. Even in mid-July, I am never watering more than once every two to three days. How long you water depends on whether you have a drip irrigation system or an overhead watering system and if you have mulched your plants (see below). I often do the finger test to check soil moisture if I'm unsure. A finger test means that you stick your index finger in the soil, up to the knuckle. If the soil feels moist, then there is no need to water.
Build your soil
As gardeners, we are already aware that a healthy soil rich in organic matter and living microorganisms is the foundation of our gardens. As you know, I’m a strong proponent of compost and indeed, adding compost to our garden soil year after year serves to increase its water holding capacity. According to Washington State University Extension, a 5% increase in organic material quadruples the soil’s water holding capacity.
Soils that are rich in organic matter have a sponge-like quality, allowing them to absorb and retain more moisture over a longer period of time. Improving your soil structure through the addition of organic matter means that the rain that already falls on your site in May and June, for example, is infiltrating the soil rather than running erosively off the surface. With our clay soils, we want to be especially conscious of building up a crumbly structure so that our soil can properly absorb water rather than becoming a hard pan by the middle of July.
Mulch your plants
Applying a 4 to 6-inch layer of mulch (either straw or leaves) between your plants will complement your soil-building efforts and cut down on your watering. Mulch keeps the soil and the plant roots cool during the summer months while maintaining a more consistent soil moisture. This translates into less frequent watering and less water stress on the plants. It also has the added bonus of smothering weeds. As the straw and leaves breakdown, they will also contribute organic matter to the soil.
Planting your plants densely, using hexagonal spacing, allows them to form their own living mulch. Similar to straw or leaf mulch, the plants themselves will shade the soil, increasing soil moisture retention and decreasing weed growth.
If you want to go even further in terms of water conservation, observe and assess your site in terms of your water capture options. In the field of permaculture, there is a design principle when it comes to water – identify as many ways to slow, spread, sink and store water on your site. Although there is always the garden hose attached to your well or city water, to truly create a more resilient and drought-proof site, building redundancy in your system in terms of water supply is a smart design move. For example, can you capture water off of your roof and run it into rain barrels, a pond, a rain garden or a swale? Are there options to reuse water in your system?
Setting up some of these water capture systems will decrease your use and dependence on city water, while at the same time help to build a more resilient growing site.
What other water conservation strategies do you use in your garden? Please share them in the comments below!