Vegetable garden practices for summer
Published: Saturday, July 6, 2013 at 6:01 a.m.
Last Modified: Wednesday, July 3, 2013 at 12:07 p.m.
The climate and weather of North Central Florida dictate a period of dormancy in the summer vegetable garden.
With the exception of peppers, okra and sweet potatoes, the combination of rain, hot temperatures and high humidity are simply too much for most vegetable crops. Even with this hiatus from production, there still are some activities gardeners can participate in during the summer. By now, plants from the spring vegetable garden should have been removed, and in some gardens, with a lack of attention, most likely the weeds have taken over. For vegetable gardeners, summer is a time to take off from the rigors of watering, weeding and scouting for insect and disease pests. If you used mulch in your spring garden, it probably will continue to provide some level of weed control, but there may be better alternatives, and if no action has yet been taken, early July is the perfect time to begin.
Typically in mid-June, production decreases and pressure from insects and disease builds. This is the time to “bite the bullet” and remove plants that are still producing. Generally, by June 15, the productive life of the plant has been used up, and in the interest of curbing the buildup of insect and nematode populations for future years, relocation of the plant to the compost pile is the prudent course of action. Having worked all spring in the garden and with the onset of increasingly hot weather, the temptation at the end of the season is to turn off the water and let the garden go. Anyone who has done this knows electing this option means a lot of hard work come fall when the time comes to install cool-season vegetables.
A better option is to remove plants from the garden, till the garden and solarize for the summer. Solarization is a recommended practice to temporarily reduce the buildup of nematode populations. Nematodes are microscopic roundworms, several types of which are present in Florida soils. The root knot nematode is one of the most damaging for vegetables and ornamental plants, while the sting nematode is generally a greater problem for turfgrass. The root knot nematode enters the plant root tissue and feeds causing galls, root swelling, stunted growth, wilting and sometimes death of the plant. On fleshy roots and underground tubers, cracking, splitting and pimply bumps may result. Nematodes build up gradually over time and are promoted by replanting the same vegetables in the same place year after year.
There are some cultural practices one might employ in reducing nematodes, including application of organic soil amendments (leaves, grass, animal manure, etc.), crop rotation and solarization. It is this practice of soil solarization, using heat to reduce nematode populations, one should employ in the garden during the summer months. The process is simple, yet effective. First, remove all vegetative matter from the garden, then plow, rototill or spade the soil. Dampen the plowed area, then cover with clear plastic (4 mil works well). Do not use black plastic as it is important for sunlight to penetrate to the soil. The objective is to reach temperatures above 130 degrees under the plastic, which will effectively reduce nematode populations. Plan for the plastic to remain for six weeks, preferably the warmest six weeks of summer (early July through mid-August).
There are other benefits to the practice of soil solarization. Soil pests such as wilt fungi, and some insects as well as weeds, are killed by prolonged exposure to these high temperatures. Further, the appearance of the garden in summer is enhanced, weeds are controlled (and therefore won't have the chance to produce seed for next year), and when fall arrives you'll have a nice surface to begin preparation of the fall vegetable garden.
As with all things, prudence has its price. The cost of plastic has risen in recent years, so one will need to weigh carefully the price of soil solarization. If removed after a six-week period, the plastic should still be good for a second year. Plastic breaks down in sunlight, so leaving it longer than six weeks will likely curb the opportunity to use it in a subsequent year. In consideration of the benefits, particularly increased yields, the price of solarization is still a good choice for most gardeners.
David Holmes is Marion County extension director. Contact him at firstname.lastname@example.org.