For newer gardeners, cool, gray maritime summers can tempt a person to skimp on watering. Surely it’s about to rain, right? Unfortunately, summer rain is often drizzle, enough to dampen the dust but rarely enough to satisfy the needs of our plants. Remember, although Washington is no longer in a state of extreme drought, we’ve been in drought for several years and still are, despite the rainy spring.
As a rule, unless your garden has enjoyed at least an inch of free rainwater every week, both edible and ornamental plants in active growth really DO need to be watered. One good way to reduce water use is to layer beds and borders with compost and a loose, airy topdressing such as medium-grind wood chips (NOT bark). Too ugly? By early summer, you shouldn’t be able to see the ground between plants so the chips will barely show, if at all. That combination helps soil retain moisture and reduces evaporation loss on warm and/or windy days.
Several readers asked about rain barrels and wondered if they could be used for drinking water in an emergency. Well, yes and no: Rainwater held in barrels that capture water off the roof of a building can be used freely on lawns and ornamental borders. But, water can leach chemicals from roofing materials, from shingles to treated shakes. These can include asphalt, tar and glue, petroleum by-products, glass particles, lead and more. Metal roofs can shed zinc, copper and aluminum as well. Some of those chemicals can react with water, especially acidic rain, and bind the funky substances so they stay in your water barrel. Ick, right?
All rooftops also accumulate bird and animal droppings, pollen, dust and dirt, slime molds and other unsavory things, all of which will affect the quality and cleanliness of the rainwater. While the water stands around for a few months, pathogens often develop, as they would in any bucket over time. All that said, stored water from a rain barrel that’s equipped with a good charcoal filter can be used on edibles as well as ornamentals (but change the filter every year).
Midsummer is a good time to empty all water storage containers, which should be done annually. As mentioned, you can use the unfiltered water on ornamental garden beds and lawns or for washing the car, etc. Empty each barrel completely, then rinse it out with a mild bleach solution (or scrub until clean if it’s slimy). If you just want to use a rain barrel for garden irrigation, any clean container with a filter and a fitted cover will do. If you’re looking to store potential drinking water, it’s best to use containers designed for that use, preferably the kind with a hose attachment at the bottom (this makes garden watering easy). If you envision needing a lot of water during a prolonged emergency, consider more complex filtration systems such as the Lifestraw Community water purifier, which removes most particulate matter.
Before using any new water barrel, rinse it out with bleach water as above, making sure any plastic bits are flushed out. To keep stored water potable for up to a year, add 4-1/2 teaspoons of bleach per 55 gallons of water. Store the barrels in a shaded place where they won’t heat up in summer weather. If the hose attachment is near the very bottom of the barrel, set the barrel on blocks to make it easier to get the hose on and off (trust me on this one). Onward, right?
Contact Ann Lovejoy at 413 Madrona Way NE, Bainbridge Island, WA 98110 or visit Ann’s blog at http://www.loghouseplants.com/blogs/greengardening/ and leave a question/comment.