No Till Gardening Southern California

By SCMG and Food Gardening Editor Stephanie Wrightson

Singing Frogs Farm 1

After one year, I made it to the top of a Sonoma County community garden wait list. My generously large plot was in an expanded area of the garden where no one had ever gardened – in other words, clay and rock. My husband tried using a pick axe; then, we paid a neighbor's grandson to finish pick axing. Next, I incorporated a truckload of compost into the top 8-10 inches. After that huge effort, I never dug in compost again. Instead, I would arrive mid-day when the early, industrious community gardeners were home, and lazily spread a few bags on top of the soil when I was transitioning between seasons. Now I find that I have nothing about which to feel guilty!

The University of California is promoting conservation agriculture which involves seven principles to conserve natural resources and improve farmers' production:
•   Minimum soil disturbance
•   Preservation of residues that provide permanent soil cover
•   Diverse crop rotations
•   Use of cover crops
•   Integrated pest management
•   Reliance on precision, highly-efficient irrigation
•   Controlled or limited mechanical traffic over agricultural soils

One of the seven principles that is gaining huge popularity in the home food garden is minimum soil disturbance—"no-till" to some. This is nothing new. No-till farming has been practiced for hundreds of years. And master gardeners have long espoused the nurturing of macro- and microorganisms and the preservation of soil structure through minimum soil disturbance. What IS relatively new is the widely-documented research that supports this practice as well as the push from U.S. agricultural universities.

Singing Frogs Farm 2

What are the advantages of minimum soil disturbance besides the reduced physical effort that I was trying to achieve?

•   By applying compost and fertilizers to the top of the soil, we are providing nutrition close to where biological activity and aeration is best.
•   Tilling brings up weed seeds.
•   No-till doesn't disturb earthworms, fungi and other macro- and microorganisms.
•   Undug soil is better able to maintain humus—meaning improved plant nutrition, disease resistance, soil aeration and water holding capability.
•   Undug soil retains (vs. releases) carbon dioxide and, by adding compost, the soil's carbon absorption ability is increased.
•   There is better water retention. Increased levels of soil aggregations allow for higher water infiltration and greater soil water storage capacity. The untilled soil is able to build up a system of pores that move water up, down and sideways resulting in more efficient use of water. Also, there is a reduced likelihood that elements will enter the atmosphere as greenhouse gases or be leached to groundwater.
•   Living roots can be kept in the soil.
•   Plant growth (production) is boosted as the result of healthy soil life, improved irrigation, etc.

There are strong, even passionate, feelings around no-till. To some, tilling the soil is a sin. Many would be aghast to hear that a home gardener rototills their vegetable bed every year. Soil scientists state that tilling only should be done for a useful purpose because frequent stirring or cultivation results in soil structure breakdown.

So, what would a useful purpose be for tilling the soil? Perhaps the following:

•   A one-time tilling of a new bed to break up compacted soil or sticky clay by incorporating large amounts of organic matter.
•   A one-time tilling to remove massive and invasive roots.
•   A one-time tilling for a quick change in soil acidity (i.e., incorporating limestone or sulfur) which is a rare need for most gardeners.
•   A one-time tilling to loosen soil in order to remove thick, large, invasive weeds in a new food garden, and where other organic methods are ineffective.
•   Shallow tilling to make seed beds (soil particles must be small enough so that seeds can germinate easily). Many "no-till" gardeners start seed indoors and transplant seedlings with minimum soil disturbance.

So, where does this leave us? There seems to be a strong case for minimum soil disturbance, but this may not be feasible in every home garden situation as described above. As for me, I'm taking a mea culpa moment for my past tilling indiscretions followed by celebration that, by spreading compost on top of the soil without digging it in, I'm being a good steward of the land by practicing minimum soil disturbance. Now I have time to put my feet up at the end of the day. Ahhhhhhhhhh!