Hot and dry: Managing with limited water
July 12, 2013
When temperatures soared into the hundreds last week, I decided to give my vegetable garden a good soak ahead of schedule.
It had been three days since the last deep irrigation, and would be another full day of heat before the next scheduled deep watering.
Water is precious. When I turned on the system, there was none. Soon I learned that PG&E "routine maintenance" stopped the flow of irrigation water in the Sonntag canal and others in the region.
Many farmers and gardeners in the Chicago Park and Peardale areas were affected.
My highest priority was to keep irrigated the approximately 1,500 cuttings done by my propagation students in June. They would not be misted. Roughly half were in a "cold frame" where midday temperatures on a hot day may soar to above 120 degrees when there is no water for cooling.
These had some protection from 40-percent shade cloth.
All the propagated cuttings survived with no damage by running a hose from the well some distance away.
The cuttings in the hottest exposure were assisted by the roots that had already developed in only three weeks.
The more recent class work was still on the picnic tables where class had been held, covered with 60-percent shade cloth.
The vegetable garden is too far away and too large to be saved by well water. For a few very hot days, it did without.
Deep mulches of decomposing wheat straw and 30-percent shade cloth over the plants were in place.
When water was available again, it had been more than five full days of heat with no irrigation. Fortunately, there were no young seedlings (I would have carried water!).
All the summer vegetables looked great! Even the sweet peas were still in full bloom, although stems were shorter.
Tomatoes did not even wilt in the heat of the day without irrigation for five days.
I credit the 6-inch deep straw mulch. The plants are thriving in my fertile soil, and this year the growth is far ahead of past years. Just a lucky spring for me, with no frost in May.
The first tomatoes were ripe June 28, the 36-year anniversary of my first garden on Sonntag Hill. I picked Costuluto Genovese (an Italian heirloom), Early Girl, Sweet Million and Black Cherry.
I focus on water efficiency in my landscape choices. One of my favorite summer-blooming small trees is the chaste tree (Vitex agnus-castus), native to the Mediterranean region into central Asia.
If you are in the Cedar Ridge area, stop by the post office soon, where a specimen of this July bloomer is now covered with blue flowers.
This particular tree appears to have a history of winter damage.
Since the day of dedication of the new post office (the fourth) was in November 1989, my guess would be that a young Vitex was pushed over by the heavy snows in February 1990.
No one thought to straighten it in its youth, so it grows leaning to the east, hardly apparent when it is in full bloom.
Large clusters of blue flowers open in early July and continue into August.
Two white-flowering cultivars of Vitex include Alba and Silver Spire. Even as blooms fade, the attractive gray-green leaves hold their beauty through the summer heat.
In winter the gray bark and seed heads add a seasonal dimension to the landscape.
A deer-resistant tree (sometimes grown as a shrub) for full sun and small spaces, the chaste tree needs very little summer irrigation, although it will tolerate water once a week if the drainage is good.
Winter drainage is just as important, which makes this a good choice for sunny slopes.
In foothill areas, with our cold winters, Vitex grows to about 15 feet in height and spread. In warmer climates of California, the mature height and spread is greater, to 25 feet.
This is a wonderful water-efficient insectary plant. As I watched the honeybees and native bees forage in the Vitex blooms in Cedar Ridge last week, my attention was captivated. Concerns about the lack of water in my vegetable garden were no longer immediate.
Join me July 20 for the Colfax Garden Tour, six special private gardens from lower Colfax to Applegate. Tickets are available at Hills Flat Nursery, Prospector's Nursery and Weiss Brothers' Nursery.
Carolyn Singer has gardened organically in Nevada County since 1977. She is the author of the award-winning "The Seasoned Gardener, 5 decades of sustainable and practical garden wisdom," and two volumes of "Deer in My Garden" (deer-resistant plants), available locally. For more information, visit http://www.carolynsingergardens.com.