As we move into the hottest months of the year it is a great time to think about water.
Our fresh water is a limited resource in the summer months, and watering restrictions are important to follow. Beyond saving a valuable resource, there are other reasons why you should not over-water your vegetables. Too much water can increase diseases, root rot and blight. There are tomato aficionados who claim that too much water decreases flavour significantly.
How much water do your vegetables really need? The answer is: it depends. You may have heard the rule, “an inch of water a week.” This works as a good guideline in the spring, but I find that in the heat of summer it is more like two inches (five centimetres) a week.
A rain gauge or plastic container set out in your garden will measure this for you if you can check it before the sun evaporates the
water collected.
I find that the best way to tell if my garden needs water is to stick two fingers into the soil two knuckles deep. If the soil is cool and damp, no watering is needed. If it is bone dry, it is time to water. However, for newly seeded areas, try to keep them moist until they germinate (you can see green sprouts). I like this method because you don’t need to know your soil type or how much it has rained this week, you just use your sense of touch. If you see wilting plants, you have definitely gone too long since watering.
Your soil is a huge determining factor in how much you will need to water your garden. If you have rich loamy soil that you’ve amended with compost for years and built up an amazing collection of organic matter in, you’ll need less water. The organic matter will act as a sponge, staying moister longer than sandy soils. If you haven’t started composting, now is a great time to build up this valuable resource.
Adding mulch to your garden beds (a nice thick layer, 10-15 cm, or four-six inches, of straw or dead leaves) will do wonders for keeping moisture in your soil. Add mulch when your seedlings are tall enough to keep their leaves above the mulch layer, and don’t try direct seeding into mulch – your seeds will just get lost. When you first apply the layer of mulch give it a good soaking, which will help it stay in place and absorb more water in the future. Over time this layer of mulch will break down, and this is a fantastic way to add organic matter to your soil.
While watering your garden you are also “training” your plants’ roots. Do you want to train them to go deep or to spread out just under the soil? When you water every day for a few minutes, the top inch or less of your soil will get wet. This trains your plants to look only in that top layer for water, and send most of their roots into this area. On a hot day this top inch of soil can heat up and can cause stress or burning to the roots, and your plant has little to no ability to search out water if you forget to provide it.
On the other hand, if you water long enough for it to trickle down deeper than two inches below the soil surface, the roots are trained to go deep, and are less susceptible to water and heat stress. I also believe that this method of watering uses less water because more of it is soaked deep into the ground versus evaporating from the soil surface on a daily basis. This method of watering may take 30 minutes to complete, but depending on the weather you may only need to do it once a week.
How we irrigate also influences how much water our gardens require to thrive. Reducing or eliminating evaporation is the key factor here. Sprinklers and overhead watering has the most evaporation, then hand watering with a hose, and drip irrigation has the least. Drip irrigation can save 40-50 per cent more water than a sprinkler! Drip irrigation is more expensive to install and is not very well suited for newly seeded areas; however, it is fantastic for long season crops, like tomatoes or squash, that like consistent watering and are typically planted as seedlings.
The North Shore Neighbourhood House’s Edible Garden Project will be installing water conserving irrigation and hosting hands-on educational opportunities for the community to get involved thanks to generous support from the RBC Foundation, and the City of North Vancouver’s Living City Grant. For more information on how you can get involved, visit ediblegardenproject.com.
Happy gardening!
Emily Jubenvill grew up on the North Shore and is passionate about growing fresh organic food. She’s starting an organic farm, and working for the North Shore Neighbourhood House’s Edible Garden Project. [email protected]
