By Master Gardener Lesley Arrandale
This seems like a simple question, but it’s an important one, because soil — rather than “dirt” — can be considered the basis of all life. Whether it is the sands of the sea shore and deserts, or the thick alluvial muds of grand rivers like the Mississippi, soils harbor and support millions of tiny organisms or microbes — animal, vegetable, and fungal. They form a community of creatures that we are oblivious to, but which are vital to soil fertility and its ability to support the plant life on which we depend.
We have come a long way since the advent of industrial farming, but it’s a relatively recent development. Once considered to be the scientific answer to feeding increasing numbers of people, which it certainly does, some growers are opting to use organic farming methods, aiming specifically at protecting and building up soil fertility without the use of synthetic fertilizers derived from petroleum: http://edis.ifas.ufl.edu/pdffiles/AG/AG24600.pdf. It is worth looking at our own practices to see if we can be kinder to our soil and nourish those unseen microbes.
As summer progresses, grass seems to grow ever quicker and taller, and needs mowing at least once a week. By cutting off no more than one-third of its height, we can leave the grass trimmings on the lawn and in the heat and rain they will quickly decompose, returning nitrogen and other elements to the soil. Leaves drop throughout the year, but not so much in summer and, with the exception of southern magnolia leaves, they can be shredded while mowing with no need for raking.
For flower beds and vegetable gardens, return as much weedy debris to the soil as is practical by tucking it under the mulch and it will compost in place. If you have of a lot of yard trimmings, a well-constructed compost pile will rot down in summer in just a few months. Dispose of weed seeds and any weeds that will regrow from small pieces of stem or root, like dollar weed and Florida betony.
Practitioners of “no till” farming are well aware of the benefits of undisturbed soils: they leave crop roots and debris in place after harvest and use a modified planting system for subsequent crops (https://tinyurl.com/ydfy3mlx). The soil structure remains relatively intact and nutrients are recycled directly back into the field. In our gardens we can cut off and compost the top growth of annuals and leave the roots in the ground, adding mulch to keep beds tidy. With minimal soil disturbance the beneficial web of fungal mycelium — the underground part of fungi — is left undisturbed to continue doing its job, which includes processing nutrients and making them available to growing plants. Beans and other legumes are among the plants that have symbiotic relationships with particular species of mycelia, and adding a commercially available bean inoculant to the soil at planting time is an effective way to boost productivity.
In the home garden, another way to boost organic matter is to grow a cover crop, like clover or field peas, which is turned back into the soil when still immature before sowing the next food crop (https://tinyurl.com/y8v73rxv).
Ultimately our gardens will benefit if we take care of our soil. Incorporating organic matter will keep up fertility, encourage an airy soil structure that will absorb irrigation, slow the leaching of nutrients from sandy soils, and enable plant roots to grow wide and deep. In addition, minimize soil disturbance and the natural fungal processes and microbes at work in the soil will thrive and our gardens will benefit. Your fall garden could be spectacular!