Monday, April 13, 2015

To Till or Not to Till, That is the Question

There are many reasons why gardeners till their soil before planting; historically the reasons for tilling are to remove weeds, loosen and aerate the soil, and incorporate organic matter such as compost or manure into lower soil layers. Others gardeners till their gardens out of habit, because they love fluffy soil in the spring; they saw their parents or grandparents tilling their gardens so they do the same.

Good soil is the foundation of every garden. In each tablespoon of healthy garden soil there are scores of living microorganisms. These microscopic creatures all serve a valuable purpose. They acquire nutrients from the soil, passing them along to plants in exchange for carbohydrates, suppress disease and break down soil organic matter to help build fertility. This delicate, complex structure of life beneath the soil’s surface is fragile and it is important that we disturb it as little as possible. Leaving soil unturned means the fragile soil web in the soil remains intact and can function at its prime. 

With ‘no-till’ gardening, once the bed is established the surface is never disturbed. (I have to admit, I personally like to till newly formed beds and planting spaces but I only do this once and then never again.  When planting in raised beds or pots, I of course do not till.)

When no-till techniques are in place, existing weeds aren't turned under as they are with tilling; instead, they’re smothered with mulch. By adding material in layers, the underlying soil remains spongy, making it easier for young roots and newly planted seedlings to work through the soil, this is similar to the way soil is formed in nature. Tilling brings viable weed seeds to the surface and enables them to germinate, the mulches no-till gardeners use bury the seeds deeper where they remain dormant.

No-till methods also offer increased protection from soil erosion and can cut down on irrigation needs because of the heavy use of mulches.  While gardener may want to ‘dig in’ soil amendments, digging moves surface organic material deeper, where there is less oxygen to support the decomposition of this material. Amendments such as compost, manure, peat, lime and fertilizer are ‘top dressed’, i.e. added to the top of the bed where they will be pulled into the subsoil by watering and the activity of subsoil organisms.

Over time, the mulch layers you keep adding will help loosen up the clay soil.  When you are ready to plant in the spring, push aside the mulch layer where you want to put your seeds or starts.

Good luck and happy gardening!


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