According to archaeologists, gardeners have been piling mulches on top of their soil for at least 2,000 years now. Why?
Well, mulch insulates the garden against the results of temperature extremes. In our North Texas case, that would be mostly dehydration from summer heat or drought.
Mulch’s job description includes the following tasks: (1) slows water evaporation from the soil; (2) provides air conditioning for soil organisms and plant roots; (3) smothers weeds; and, (4) organic mulches decompose and– over the long-term– contribute to soil tilth and fertility.
In short, mulch improves gardens, keeps the water bill somewhere near reasonable, recycles all kinds of garbage, plus conserves water in reservoirs and aquifers against future droughts.
Mulches come in two varieties: inorganic stuff like plastics, shredded rubber and rocks; and, organic materials like plant matter and manures.
Both variations on the theme will decompose, but don’t hold your breath waiting for rubberized mulch to disappear in this lifetime.
The array of organic mulches is dazzling and you can custom mix them by the bag or the truckload, depending on the source.
New gardeners wrestle with the question of how much mulch.
Extension Agents and Square Foot Garden aficionados suggest three- to four-inches of mulch around plants, leaving one-inch of space around the stems, to allow water to seep into the ground at source of the roots.
Water conservationists will tell you to pile two- to four-inches of compost between the soil surface and the mulch. Now there’s one powerful idea.
Sufficient mulch blocks light and darkness prevents a lot of weed emergence. If that doesn’t make you giddy about less weeding, over time mulching can double your vegetable and fruit production; and, you can plant more in smaller spaces. Ah, the secret of Square-Foot gardening!
Mid-growing season soil cultivation is unnecessary if you are serious about compost and mulch.
Organic mulches are dead and often digested plant matter. They compact and decompose during the growing season, so plan to replenish as the soil level visibly decreases. Remember, the magic depth is four-inches.
If you have clay soil, mulch is the gift that keeps on giving.
About mid-November till in the leftovers– and next spring–, your soil will be better than it was this past spring.
The rule of thumb is don’t till well-mulched soil, but if your HOA restricts lawn spaces to Bermuda grass, the stolons will invade the garden from down below then peek out to say “Remember me?”
I spread out uprooted invaders to shrivel and die in the sun, then used the straw corpses to mulch.
Garden soil improves with every layer of mulch, because the insulation helps feed, clothe and house the diverse community of microbes and macrobes that break down minerals plants take in at the roots.