No-Till Food Gardening
By SCMG and Food Gardening Editor Stephanie Wrightson
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.
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!