THE ORGANIC ‘NO-TILL’ METHOD

As an organic gardener, rototilling is one of the most damaging practices we can bestow on our garden soils.  Soil turning is so ingrained in the psyche of the home gardener and large-scale farmer, that we tend to overlook the importance and necessity of soil organisms as natures rototillers.  Jethro Tull (1674-1741) was the inventor of the horse drawn plow, and thought that tilling and pulverizing soil particles made nutrients more available to plant roots, and loosened the soil for better root growth.   Tull wrote extensively on the subject of tilling (plowing), and his writings caught the attention of farmers like George Washington and Thomas Jefferson, who encouraged their fellow Americans to break up the soils.  The end result is that most home gardeners and farmers still till their soils annually, even though tilling has been proven damaging to soils.

One teaspoon of healthy soil contains up to 9 billion living macro and microorganisms.  These organisms are nature’s rototillers.  Soil organisms such as earthworms; create vertical and horizontal tunnels throughout the soil matrix as they search for food.  These tunnels help to loosen soil structure, and provide better drainage and air space throughout the soil, which help plant roots grow rapidly.  Beneficial fungi such as mycorrhizal fungi, attach themselves to plant roots and extend out into the soil up to 900 times farther than the roots of plants can by themselves.  These mycorrhizal fungi actively search for water and nutrients depending on the plants particular needs.  Beneficial fungi help to protect plant roots from disease, drought, malnutrition, soil compaction and pest insects.  Another helpful group of microorganisms are bacteria, which help make nutrients readily available for plant root uptake.  Bacteria are stratified in the soil at three levels according to specific temperatures that each group thrives at.  Psychophilic bacteria work best at temperatures less than 40 degrees F.  Mesophilic bacteria work best at 40 to 100 degrees F, while Thermophilic bacteria function best at 100-180 degrees F.  All of the above mentioned groups of soil organisms, with the help of nematodes and protozoa, decompose plant and animal waste, converting organic debris into plant food.  Additionally, soil organism’s help to reduce soil erosion and compaction. Microbes accomplish this by not only creating tunnels through the soil, but also by exuding sticky substances (polysaccharides and other exudates) that hold soil particles together.  

Tilling and plowing not only destroys soil structure, but also displaces soil organisms into areas of the soil where they cannot survive.  Tilling soils completely chops up and destroys the network of beneficial fungi that are helping to pull nutrients and water into plant roots, as well as providing plant roots with a last line of defense from pest insects and disease. Worm tunnels and pores between soil particles are torn apart by tilling, ultimately reducing air and water movement throughout the soil matrix.  Sure, the soil is fluffy after rototilling, but the first time water hits the disturbed soil, it begins to compact.  Soil compaction through rain and irrigation continues to reduce air and water space until plant roots can no longer penetrate deep into soil to access nutrients and water.  Tilling also promotes excessive soil erosion, because all those exudates (microbe glues) that were holding soil particles together are pulverized.  Excessive weed growth is another repercussion of inverting soils. Tillers expose dormant weed seed from deep within the soil profile, exposing the seed to light, air and moisture, all of which are conducive to weed seed germination. Lastly, rototilling overly oxygenates the soil, which can accelerates organic matter break down in the soil, eventually reducing total soil organic matter, an essential component to all healthy soils.

An alternative to tilling soils is to grow ‘living mulches’ or cover crops, sown in the autumn, across all areas to be planted with vegetables and annual row crops during spring.  Living mulches such as red, white and sweet clover, annual rye, hairy vetch and alfalfa help to lock soil in place, preventing soil erosion on otherwise barren soils.  Living mulches also help to loosen clay soils as their roots penetrate deep into hardpan clay, promoting healthier vegetable root growth.  Many living mulches help to fix atmospheric nitrogen in their roots, providing vegetables with a ready source of nitrogen in the spring and summer when they need it most.  Living mulches also help to choke out weedy invaders by shading and smothering them before they have a chance to take root.   As cover crops begin to die, they provide an excellent source of biomass for microorganisms to use as food, which in turn, helps to create better nutrient availability for vegetable roots.  Simply remove a small area of the living mulch in order to make room for spring vegetable plantings, while leaving the remaining living mulch in place.

Compost is an excellent amendment for organic ‘No Till’ vegetable beds because the organic matter in compost helps to replace the nutrients that are taken up annually by crops and soil microbes.  Rather than tilling, simply apply six inches of compost to all beds that are to be planted.  Compost can be applied in the spring or fall, as long as the compost has been allowed to decompose for one to two years prior to use.  Compost will encourage soil ‘tilling’organisms that will loosen soil structure, reduce soil erosion and make nutrients more available for plant root uptake.  Once beds have been composted, apply a layer of organic mulch a top the newly composted bed areas.  Mulch choices such as wheat straw, partially composted wood chips and leaves as well as pine straw, work well to discourage weed growth, reduce soil erosion and compaction and prevent excessive water loss through evaporation.  For added weed prevention and moisture loss reduction, one can apply 8-10 layers of newspaper directly on top of compost prior to mulching.  Be sure to overlap newspaper edges 6”-8” (like a shingled roof) so as to prevent weeds from slipping through the gaps between newspaper edges.  Once bed areas are covered in newspaper, apply enough mulch to thoroughly cover all exposed newspaper.

Organic gardening is a system that works with the natural processes of our soil, air and water.  Fortunately for us, nature is a check and balance system that helps to minimize a plethora of disease, pest insect, weeds and soil disturbances that would otherwise impede plant growth.  We should not try to perfect an already perfect system by tilling and applying manmade chemicals to our soils, as this only reduces the effectiveness of the natural processes.  Every time we apply a chemical fertilizer or pesticide to our soils, we disrupt the ecological balance, and create soils that are dependent on humans, not soil life, to sustain them.  Let us work with the natural processes, and we will be rewarded with less work, healthier harvests and more time to enjoy our gardens!  At Marvin’s Organic Gardens, we promote safe and organic alternatives for home gardeners and farmers, no matter what the problem is at hand.  For every pest, weed, disease and soil issue, there is always a natural approach.   We would be more than glad to help you Go Organic, It’s Only Natural!  For questions, please contact Wes Duren at wes@marvinsorganicgardens.com or call us at 513-932-3319.