Archaeologists say gardeners have been mulching for at least 2,000 years. Mulch is how we insulate the garden against the results of extreme temperatures.
Southern Denton County gardeners mulch because (1) it slows water evaporation from the soil, (2) it provides natural air conditioning for soil organisms and plant roots, (3) weeds don’t like it, and (4) organic mulches decompose and contribute to soil till-ability (Middle English “tilth”) and fertility. In short, mulch improves suburban gardens, keeps the summer water bill under control, recycles all kinds of garbage, and conserves reservoir water against future droughts.
Mulch comes in two varieties: inorganic (plastics, shredded rubber, rocks) and organic (plant matter, manures). Both varieties decompose, but the question is will you or your inorganic mulch decompose first? Mother Nature produces a huge array of organic mulches you can custom mix or buy in bags or truckloads.
New gardeners ask, “How much organic mulch do I need?” Extension Agents and Square Foot Garden experts suggest 3-4” of mulch around the plants, leaving about 1” of space around their stems. Sufficient mulch eliminates light, and that prevents most weed emergence. If that good news doesn’t make you giddy, mulch can double your vegetable production, and you can plant intensively — more stuff in a smaller space– part of the Square Foot Garden’s secret. Cultivating the soil under a serious layer of mulch is unnecessary during Texas’ two growing seasons.
Organic mulches, which are dead and often ABC (Already Been Chewed) plant matter, compact and decompose so gardeners must replenish mulch throughout the growing seasons to maintain that desirable 4” depth. Mulch is the gift that keeps on giving to local clay soils because when the autumn growing season ends about mid-November local gardeners can till the soil and leftover mulch together for better soil than when we started out last spring. I know the rule of thumb is we don’t till well-mulched soil. Now hear this, neighborhoods like Lantana restrict lawns to Bermuda grass, the most invasive stuff on the suburban part of the planet. Annual tilling lets you uproot stray Bermuda grass. I spread the invaders out to shrivel and die in the sun then use the corpses to mulch my strawberries.
Garden soil improves with age because the decomposing amendments and mulch feed, clothe, and house the diverse community of subterranean organisms upon which plants thrive.