One of the most anticipated rites of spring is dusting off the tiller and heading out to the vegetable garden for a little soil play. It is one of those things you can’t plan for, though. It becomes a waiting game because we can’t do it if the soil is too wet; we don’t want to do it if it is too cold and we only have the time to do it when the weekend rolls around.
Tillage Destroys Soil Structure
Well, what would you say if I told you that you were off the hook when it comes to spring tilling? Tilling is passé; sure, it makes people happy to see a clean, freshly tilled garden, ready to receive seeds and seedlings in anticipation of a bountiful harvest. The truth is too much tilling is bad for the soil. Soil is not just dirt; it is a living organism and the more we disturb it the less alive it becomes.
Tilling the soil allows us to seed or plant the garden more easily; it also allows the developing roots to extend freely through the soil, but this is short-lived. Once rain visits the plot the pulverized soil becomes a smooth crust. Soil scientist, Lois Braun explains, “Both air and water should easily infiltrate these pores for healthy root growth and for a healthy soil microbial life. Tillage pulverizes larger clumps of soil (“aggregates”) into a fine powder which is easily washed by the next rain down into the soil’s pores, clogging them up.” Put this way, it makes a great deal of sense. We all know how important oxygen, moisture and drainage is for plant health so larger aggregate clumps of soil are ideal over finely tilled “powder” that more easily erodes or becomes compacted under foot or during spring rains.
Tillage, Decomposition, and Soil Organisms
The most important part of soil structure is organic matter. Organic matter slowly decomposes (tilling speeds up the decomposition) and as it does it feeds our plants at a rate that matches the plants ability to uptake the nutrients. Not to mention other living organisms that are in the soil that become displaced in tilled soil and may not be able to recover and function at their new depth. From earthworms to beneficial nematodes, an intricate system of life lies beneath the soil’s surface. And we forget about the white thread-like bodies of mycorrhizal fungi just beneath the soil surface that help to fix nitrogen in exchange for carbohydrates they collect from root nodes; in exchange they scavenge absorbable phosphate, making it available to our plants so we don’t have to…unless we are constantly tilling and disrupting the balance of life in the soil!
No-Till Weed Strategy
You should still use your spade, garden fork or cultivator to loosen the soil at planting, but forget tilling for weed control. Instead, try adding organic matter as mulch or newspaper covered in grass-clipping or compost to control weeds. For gardens that have good soil structure, try no-till this year and see what happens.
If you have any questions about soil structure, compost, or tilling, please call Limbwalker at 502-634-0400.