If you are like most gardeners this season, some things went really well, and some were disappointing.
Often when plants fail to thrive or veggies aren’t as productive as you hoped, soil conditions can be the cause. This fall, you can improve the soil both in your vegetable garden and in the flowerbeds where you plant annual flowers.
Adding more fertilizer as plants grow will not improve your soil. In fact too much fertilizer can cause your plants to falter. Plants grow well when there is sufficient water, sunlight and a soil that promotes healthy root growth.
Healthy soil has about 10-percent organic material mixed into it. This gives worms food. A healthy worm population makes tunnels in the soil for roots and water to follow in. The more worms, the more places for roots to expand rapidly. Healthy soil has about a dozen worms per square foot!
The organic material, especially when broken down as worm castings in the tunnels, provides nutrients for the plants. Soil with organic material worked in also has more water-holding capacity so you need not water as often since the water will not just run through the sandy soil. If you soil is heavy clay, the organic material will loosen up the soil so that water doesn’t just puddle but flows thorough the soil more effectively. In addition, roots can move through loosened clay more easily.
So how do you increase your soil’s fertility? You add organic matter in several different ways while the garden space is fallow.
First you can incorporate the compost you made this year into the soil with a shovel and rake. Dig it in down to about 8 inches. Rototilling breaks up the soil’s essential structure and kills worms, so digging is far better for the garden.
Your compost is not finished? Gather up leaves from all your neighbors or watch when the parks department is gathering leaves and ask to take home some bags of leaves. Any leaves will work except for black walnut. English walnut leaves and pine needles are fine to use. Dump the leaves on the lawn and grind them up with the lawn mower, and then dig them into the garden where they will break down this winter thanks to freezing and thawing, worms and microorganisms.
Our winters have become milder in the last 10 years, and our earliest frost has come later and later in the fall. These changes make ideal conditions for growing a cover crop such as annual rye grass or fava beans.
My friend and fellow WSU Master Gardener Emilie Fogle is an experienced cover crop grower. Her favorite cover crops are Australian pea for its nitrogen-fixing benefits and buckwheat. Any cover crop grows until the soil gets too cold. Then it becomes “green manure” when early in the spring, before it grows enough to go to seed, you dig and turn the plants into the soil. The plants’ leaves, stems and roots provide organic material as a soil amendment.
Emilie reminded me that you never want the cover crop to flower and go to seed because it will become a persistent weed. If the plants grow too rapidly before you are ready to dig them into the garden plot, mow them down, or put the family goat on the plot.
The cover crop that has been dug into the soil breaks down during the early spring, so that by the beginning of May when it is time to plant your garden, the soil has been nourished. Garden centers and farm supply stores sell seed that can be used for cover crops.
Next year, you really will notice a difference in the soil. It is easier to work and plants grow more rapidly — or at least they seem to because you will find yourself out in the garden more often cheering the plants on.
A WSU Master Gardeners of Chelan County column appears weekly in the At Home section. Bonnie Orr is one of three columnists featured.