Is your soil as soft as concrete? Does water run off the surface instead of percolating down?
Ideal soil contains 25% air and should be so soft and fluffy a hand can easily penetrate the surface.
When soil feels hard or compacted many beginning gardeners will reach for a hand tool thinking the soil needs to be cultivated or turned to loosen it up. But soil disturbance is what caused the compaction in the first place. Doing more of the same will make the situation worse.
The best fix for damaged soil is to follow the examples provided by natural systems. Forests and prairies support lush plant life without anyone ever needing to turn the soil.
Protect soil from heavy rain and irrigation
When I lived on the west coast the rain was a constant gentle drip; in Austin heavy rains pound unprotected soil into something resembling pottery. In the absence of rain, people routinely irrigate with hoses which can be just as punishing.
In natural systems twigs, leaves and other debris act like a protective blanket to slow water movement. We can replicate that situation by maintaining a thick layer of mulch on the soils in our garden plots.
Any mulch will do. Shredded leaves, grass clippings, straw, hay, wood chips. compost … use whatever is handy. In the summer, light coloured mulches are best as they reflect sunlight.
Early in July, we will be receiving some mulch from Keep Austin Beautiful. Please help yourself.
Mulch protects vulnerable underground helpers
If protected by mulch, worms — both earthworms and red wigglers — will do all the work necessary to keep soil loose and fertile.
Earthworms create long lasting tunnels deep below the surface. Red wigglers churn the area close to the surface where most vegetable plant roots are located. Their castings (worm poops) make ideal fertilizer as they contain nitrogen and other nutrients essential for plant growth. Give both these critters some time and with a little help from their bacteria friends, they will take care of all your cultivating and fertilizing jobs.
They are delicate living creatures though and have certain requirements. They need to stay moist and suffer when temperatures are extreme. Since red wigglers live so close to the surface, they are particularly vulnerable. A soft blanket of mulch will keep soil cool in the summer and warm in winter. Dry carbon rich mulches such as wood chips are sufficient for earthworms. Red wigglers need extra care. They thrive in soil routinely topped with green materials such as fresh shredded comfrey leaves and spent coffee grounds.
Without a cover soil temperatures can rise above the ambient air temperature. With a cover they can be significantly cooler — cool enough to support life even during the hottest months. And cool enough to stay moist without irrigation.
If you are taking a break from gardening due to extreme weather or vacation
please don’t abandon your garden soil. Let it rest under a protective blanket of mulch. The material should be at least 3 inches in depth. Or, plant a thick cover crop requiring little to no irrigation. The plant roots will shelter and sustain underground helpers. Leaves will shelter the soil from damaging heat and water. Some good summer choices are Sudan grass and sesame. Good winter cover crops for our area include winter wheat, vetch and clover.
Never ever cultivate wet clay-based soils. Wait until they are moist or better yet dry.
If you must aerate poke holes instead of tilling the entire surface.
Never add sand to clay soil.
Avoid stepping onto a garden surface. Use pathways or stepping stones instead.