So far we have discussed the need for a new calendar for growing vegetables, answered the question if reclaimed water was safe to use in the vegetable garden, how to grow seeds into transplants, why you should grow your own vegetables, and where you should put your garden. Now we should discuss our Central Florida soil, especially if you plan to grow your vegetables in the ground.
Growing vegetables in sandy soils has a great number of limiting factors that must be overcome, including nutrient deficiencies, acidity (pH), poor physical attributes, and low water storage. Soil is defined by its particle size, typically having low clay content, and being dominated by coarse sandy particles. This coarse sandy texture affects the ability of the soil to hold water and nutrients. In terms of water holding capacity, sandy soils of Florida have larger pores than soils with small pores, making it more difficult to hold soil water and nutrients against gravity. But if you can grow weeds, you can grow vegetables.
The relative proportion of sand, silt and clay particles determines the soil texture. It is the soil structure that determines how easy or how difficult it is for soil to hold water and nutrients in the root zone. Organic matter will do this for us if we get enough of it into the soil. Organic matter is a low analysis source of nutrients that supports soil microbial life and adds structure to the sandy soil to improve the soil’s ability to hold water and nutrients in the root zone longer than with sandy soil alone.
There are other reasons why organic matter is important to your soil and they include: the ability to maintain stable soil pH (acidity), a low analysis source of nutrients (but not a substitute for fertilizer), coats soil particles to build structure (to reduce runoff of water and nutrients), provide a food source for soil microorganisms, and bind harmful pollutants so they do not get out of the soil.
“The amount of organic matter in soil is the result of two processes: the addition of organic materials (roots, surface residue, compost, etc.), and the loss through decomposition. Soil organic matter is continuously produced and broken down by living soil microorganisms, insects, and worms as they consume it for food. Microbial activity and decomposition rates of organic matter are enhanced in warm, wet conditions, which are common in Florida.” (source: https://edis.ifas.ufl.edu/pdffiles/MG/MG45400.pdf)
Organic matter includes compost (should not contain any recognizable bits of organic matter including whole leaves, straw, sticks or large chunks), animal manures (from plant eaters and should be composted for at least six months) and yard/plant waste, kitchen waste. Regular additions are needed to maintain an adequate amount of organic matter in our garden soil. Simply add a 3” layer over the garden area and till or turn under into the top 6” of soil. Do this often, at the beginning of the gardening season with a “warm season” garden in early-August, at the beginning of the “cool season” in late-October and at the beginning of the “warm season” garden in March. You could also add organic matter in the middle of summer if you really wanted something to do in the garden.
This is one of those times where you almost can’t get enough of a good thing.