This year, California, and Sonoma County in particular, is arid land. The US Drought Monitor here classifies drought as “exceptional”, the most severe of all drought categories.
This means that each of us should do everything possible to conserve water, especially in the garden and the landscape. After describing how you can conserve water while growing edible crops, we’ll cover ways to manage irrigation this summer for existing ornamentals and landscaping.
Three principles are important for conserving water in gardens and landscapes. First, give the plants only the water they need to survive until the fall rainy season returns. Second, as much as possible, water the roots of each plant directly instead of wasting water on large sections of soil. And third, collect and use domestic water to water the plants in pots that would normally go down the drain.
Start with the vegetable garden
About 50 years ago an African farmer – whose name seems to have been lost to modern search engines – lived in a dry part of this continent and invented a super efficient way to use very little water to make grow healthy crops.
His method was simple and has been recreated in arid lands around the world. This involves opening a trench in easy-to-work garden soil about a meter wide and just as deep. Do it as long as you want, but 15 feet is a typical size. If it’s beyond your ability to dig, hire workers or someone with a backhoe.
Fill the bottom of the trench with about a foot of organic material like weeds, grass, kitchen scraps, farm animal manure, or whatever will rot. Cover it with a few inches of soil. Wet it to promote rot.
Now mix good compost with 50-50 vermiculite and add a foot of it to the trench. Wet it thoroughly. Vermiculite is an absorbent material that retains water. Spongy compost also retains water and provides nutrients. Add a few inches of garden soil on top. Fill the trench with the compost-vermiculite mixture to a few inches from the ground level, water it well, and cover the top with a mulch of grass clippings, dried leaves or peat moss to prevent evaporation.
This trench will hold water all summer, with perhaps watering in August, if necessary, to carry it into the fall. You can plant summer crops like tomatoes, eggplant, okra, peppers and beans and fall crops like peas and lettuce. Bring culinary herbs among the cultures. It might not be as big as your regular vegetable garden, but it will require a lot less water.
For potted plants on your patio or in your home or landscaping, use gray water from your sinks by fitting each bathroom sink with a plastic tub. When you wash your hands, brush your teeth, or shave, you can add this water to your potted plants. Rather than letting the bath or shower water run down the drain, close the drain and when you’re done, use that water for potted plants.
Regular soap will not harm plants. Consider diverting water from your washing machine (as long as you’re not using bleach) into 5 gallon buckets with sturdy handles. Better to water the plants with it than to let it run down the drain. Water from the tub and washing machine can be poured over the root zones of ornamental shrubs to keep them alive this summer.
If this starts to seem like a lot of work, it really isn’t. It just means making water conservation part of your daily schedule. It will also reduce your water bills.
Bury the pots
If you have overhead sprinklers providing water to your landscape, consider switching to drip irrigation which delivers water directly to the roots of an individual plant. Drip irrigation systems, where one inch plastic pipes are fed from one inch main water lines, will keep your shrubs alive with an absolute minimum of water.
In the vegetable garden, use soaker hoses arranged so that their loops are spaced 18 inches apart to keep the beds moist without overwatering. These are perforated to let the water flow slowly. Mulch applied to the pipes also helps conserve water.
If you have groups of shrubs like roses, find a place to bury an olla among them. Ollas are porous clay pots that you bury in the ground among groups of woody plants, then fill with water. The water slowly seeps through the clay, where the plant roots will find it and wrap around the pot to keep in contact with the moisture. Ollas has really reduced water consumption.
“They’ve grown in popularity,” said Nina Gerety, who has worn them for years at her Potter Green & Co. store in Cornerstone Sonoma.
She currently wears items handmade by Napa potter Debra Manfree.
“Olla is an ancient form of irrigation used in all arid regions of the world. They were used by Native Americans and in Egypt, ”she said. Ollas uses about 40% less water even than a conventional drip system.