Wednesday, April 30, 2014
Springtime… season of the mud and the muck!
Our parents and grandparents often proclaimed the old adage, “April showers bring May flowers.” Were they serious?!!? It’s the end of April, and my garden offers precious few mini daffodils to enjoy, but plenty of mud and muck!
As winter releases its hold on our gardens, we may be tempted to walk in them, but our soil structure will suffer! Each footprint we put into the soil diminishes soil pores below, which encase wisps of oxygen for our plants’ root systems. As my foot presses the soil down, compaction occurs—the enemy of healthy, desirable plants. In my Landscape Maintenance class, I learned the ONLY plants that don’t mind compacted soil are WEEDS! Dandelions and other broadleaf weeds can thrive in compacted soil—but desirable plants, trees and shrubs WANT and NEED adequate air pockets amidst their roots in order to extract their oxygen, water and nutrient requirements from the soil.
Soil structure is more fragile than some gardeners realize. A well-intentioned gardener handling a roto-tiller can easily overdo the tilling process, creating tiny “peds” or particles of soil that are too fine and easily form a crust of compacted soil after a pounding rain. Further, precious few oxygen pockets can exist in soil that is over tilled. Instead, a tiller should be used only to break up the surface, creating desirable “soil aggregates.” These aggregates form soils that are less susceptible to erosion. Bacteria plays a critical role in forming soil aggregates, since bacteria produce organic compounds called polysaccharides; these are more stable and resist decomposition long enough to hold soil particles together, forming soil aggregates. Most herbaceous plants can thrive in nutrient rich soils which also provide a structure comprised of soil aggregates of various sizes.
Enjoy springtime in your garden, but try NOT to walk in the mud and the muck!
(Sources: numerous soils classes along with four decades of backyard gardening. University of Western Australia website summarized details regarding aggregates, pores and bacteria’s role in forming soil aggregates) http://www.soilhealth.see.uwa.edu.au/processes/aggregation
M. Lynn Schmid, Certified Master Gardener