Plants (and people) aren’t the only ones suffering through this epic drought. Our soil has taken a huge hit, too.
“Our soils are scorched,” said Gisele Schoniger of Kellogg Garden Products. “They need replenishment more than fertilizer.”
Early fall is an ideal time to give our soil a much-needed lift. And after this long, dry summer, it could sure use some extra TLC.
As Kellogg’s longtime organic gardening educator, Schoniger teaches gardeners throughout the West how to take better care of their soil. She visited Sacramento recently to talk dirt and microbes with the Sacramento Rose Society.
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Drought has long-lasting side effects besides brown lawns and dead azaleas. The lack of water actually can change soil’s acidity (or pH) level.
“The less water, the higher the pH and the more alkaline your soil becomes,” she said. “The more water, the lower the pH. Organic matter helps stabilize pH and keep it in the right zone, the neutral zone (in the middle of the pH scale). If the pH is too high or too low, plants can’t use all the nutrients (available in the soil). … Organic matter stabilizes the pH and holds it there.”
Organic matter – compost, manure, shredded bark, rice hulls, coconut fiber, peat moss, kelp, bone meal and other natural amendments – do more than keep pH in balance. Start by thinking of your soil as a living organism, not just dirt. Healthy soil teems with millions of microbes that break down that organic material so plants can absorb its nutrients.
“Organic matter is the fuel that makes the whole system work,” she explained.
More organic matter also gives soil the ability to better store water, Schoniger said. “If you do nothing else the rest of this year, put down organic material around your garden.”
In its research, Kellogg found that mulch can be among the biggest water savers in your garden.
“The drought message is getting through (to gardeners),” Schoniger said. “(On average in California), 65 percent of water use goes to landscaping. A 3-inch layer of mulch will reduce water usage by 30 percent. It cuts down on evaporation while helping the soil retain the water it has.”
To make the most of mulch, Schoniger recommends a two-layer approach. First, put down a thin layer of material that’s already composted (such as commerical or homemade compost, well-aged manure, etc.). Then, top with shredded bark or wood chips. Plants and soil get immediate benefit from the bottom layer.
“And the bark will slowly break down and add more organic material,” she said.
Clay soil, such as that found in most of the Sacramento area, particularly benefits from mulch and the addition of organic matter. It comes down to chemistry.
“Clay particles have a negative charge,” Schoniger said. “Clay has a magnetic attraction for nutrients that have a positive charge. The clay soil will hold onto those nutrients that trickle down until plants need it. Sand and silt particles are neutral; they can’t hold onto those nutrients the way clay can.”
Besides adding more mulch, Schoniger also recommended “feeding the soil” in raised beds with compost and other natural amendments. After the summer harvest, vegetable beds can be depleted of nutrients. They need a boost before next spring.
If whiteflies or other bugs were a problem this summer, Schoniger suggested to fight them with worm castings. Sprinkle the castings in a circle around the plant (at the dripline for trees or shrubs), then cover with mulch and let the castings work down into the soil.
Besides being rich in nutrients, worm castings contain a substance that naturally breaks down insect skeletons, she said. But water will bead up on pure castings; they need a little mulch on top to do their garden magic.
“Worm castings are the best value you can get for your garden,” she said. “A whitefly won’t go near a plant that could break its body down.”
Reader Mary Mallory Rogers of Carmichael hasn’t taken out her front lawn – yet – but a volunteer vine has made most of the turf disappear, if only for this summer.
It all started with a little homemade compost, Rogers said.
“We compost all our kitchen waste, and use the compost as mulch,” she said. “Sometimes, seeds sprout from the compost, and we get surprise plants.
“This spring, I had many healthy seedlings coming up where I had planted sunflowers the year before,” Rogers continued. “I wanted that space for tomatoes, so I gently transplanted three 6-inch tall sprouts, that I thought were sunflowers, into a flower bed in the corner of our front lawn.”
But Rogers soon found out the transplants weren’t sunflowers, but a mystery.
“When the plants developed further leaves, they began to look like a squash or melon plant, so I decided to let the plants show me what they wanted to produce,” she said. “They grew and bloomed with lovely yellow squash blossoms through June and July. They grew out across the lawn, all the way past the peach tree, then all the way out to the street. We carefully lift the vines off the sidewalk every day, but we are running out of lawn.”
Finally, the vine revealed its true identity – and a bumper crop.
“In August, we discovered that we were producing butternut squash, a favorite ingredient in some of last winter’s cooking,” Rogers said. “Now, we are giving away squashes to family, friends and neighbors.”
When the squash are ready, Rogers posts a little sign that reads “Free Market,” and invites the neighbors to share in her surprise bounty.
Besides the free squash, there’s another plus, Rogers added. “There is only half as much lawn to mow – a side benefit.”