I’VE HEARD it bandied about that we garden in a Mediterranean climate. Really? When we don’t even have sufficient heat and sun to ripen tomatoes most summers? What we do share with Mediterranean countries is a long, droughty period in late summer. Which means that from July through mid-September, our gardens are desperate for supplemental water. For environmental and financial reasons, we need effective, efficient watering strategies.
Water is the lifeblood of plants, vital for circulation, transpiration and photosynthesis. Trees give off hundreds of gallons of water daily. Even a tomato plant loses gallons of water weekly. So, providing H2O is vital to its growth and health.
Making sure plants get sufficient water starts long before you set a sprinkler or select an irrigation system. Soil preparation is key. Water runs uselessly off bare, unimproved or severely compacted soil, which unfortunately describes most urban soils. The cure? Layer on compost so it sinks into the soil and improves its texture and absorption. A topping of organic mulch after planting keeps soil from drying out so quickly.
While it makes good sense to water vegetables and fruit (most crops need an inch of supplemental water per week during the growing season), can you justify keeping your lawn green or growing water guzzlers such as roses and hydrangeas? Grouping plants with similar water needs cuts down on the area needing irrigation and on the guilt of loving thirsty plants.
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It’s a common misconception that native plants and drought-tolerant plants, such as rosemary, sedum and lavender, get by just fine without extra water. Not true in the first couple of years, when every plant needs regular watering until well-established. After that, tough flora need less watering, but all plants need help during drought.
When and how to water? I asked Washington State University Extension urban horticulturist Linda Chalker-Scott. “In general, I tell people to look at new leaves and stems to see when plants need water,” she explains. It’s always best to water before a plant wilts.
I’ve always believed it best to water deeply and less often to encourage a plant to plunge its roots deep into the soil. But experts tell me that in challenged urban soils, plant roots stay nearer the surface, so require more frequent, shallower watering. Also, when soil gets really dried out, the water doesn’t wet the soil but runs straight through. So more frequent watering it is.
Chalker-Scott says irrigation specialists recommend drip emitters because they deliver water right to the roots where it’s needed. No water hits the leaves, which can cause and spread disease. Leaky hoses are endlessly adjustable, inexpensive and effective. A drip system in pots lets you go on vacation and return home to living rather than dead plants. Just ditch the flip-flop sprinkler, which wets foliage while losing so much water to evaporation.
Has anyone tried the new interactive technology that uses the cloud and Wi-Fi to monitor when a garden needs water? Somehow I don’t think a gardener invented these systems. Just think how many sensors are needed to keep track of all the different plants! It seems an act of alienation to check on your plants via a device. How about going outdoors on a warm night and delivering, in person, a cool drink to a tired plant?
Valerie Easton is a Seattle freelance writer. Check out her blog at www.valeaston.com.