Texas AgriLife Extension Service
Texas A&M University, College Station, Texas

July-August 2008

Fall Gardening in Texas

Celery - a heavy feeder
Celery - a heavy feeder

Soil Preparation and Fertilization

If you made a mistake by not properly preparing your garden soil last spring, now is the time to correct it. This should be done before establishing the fall garden, because soil problems encountered during the spring growing season can be expected in the fall also.

Adding liberal amounts of organic matter to all types of garden soils is a highly recommended practice. Hay, compost, rotten grass clippings, or leaves, applied to the garden surface 2 to 3 inches deep and tilled or worked into the soil, greatly improve sands or clays.

Heavy clay soils, which are sticky when wet and hard as a brick when dry, are much easier to cultivate if a washed, coarse sand is added. Washing sand removes calcium carbonate, which makes alkaline soils even more alkaline. Add 3 inches of sand to the garden surface if the soil is to be tilled to a 10-inch depth.

Gypsum (calcium sulfate) added to a ‘sticky’ soil makes it more workable. Gypsum is a neutral product which does not increase or decrease the soil’s alkalinity. Not only is it a good soil conditioner, but it also furnishes certain amounts of calcium, which may prevent such minor element disorders as blossom-end rot of tomatoes and cabbage leaf-tip burn.

Never add lime or wood ashes to alkaline soils. Use iron sulfate or a chelated iron product in the soil to prevent plant yellowing (iron chlorosis) caused by lack of iron. Adding fertilizer to the fall crop is necessary because spring fertilizer has washed out of the soil or been used for plant growth. Use a slow-release fertilizer at a rate of 3 pounds per 100 square feet. If manures are used, 20 to 50 pounds per 100 square feet should be adequate. Incorporate fresh manure into the soil several weeks before planting.

Thoroughly pulverize soils at least 10 inches deep. Mix the above ingredients into the garden, and add nematicide if necessary. A properly prepared soil insures a successful fall flower and vegetable garden rather than a disappointing failure.

Additional amounts of fertilizer are needed later in the season to insure optimum plant growth and production. Add 1-1/2 ounces (3 tablespoons) of ammonium sulfate per 10 feet of row to cucumbers, cantaloupes, eggplants, okra, peas and beans, peppers, squash, and tomatoes after the first fruits are set, after the first harvest, and every 3 to 4 weeks thereafter.

Broccoli, cabbage, cauliflower, collards, kale, lettuce, mustard, spinach, and turnip greens require 1-1/2 to 2 ounces (4 tablespoons) of ammonium sulfate per 10 feet of row 2 weeks after transplanting or 4 weeks after sowing seed. Flowering annuals require 2 ounces (4 tablespoons) of ammonium sulfate every 4 to 8 weeks for the life of the plants. Sandy soils need more frequent fertilization than heavy clay soils. Crops such as beets, carrots, potatoes, radishes, turnips, and watermelons usually do not need additional fertilization. Excessive amounts of nitrogen reduce yields, or lower quality, or both.

Use Drip Irrigation

One of the best ways to water a garden is by using a drip irrigation system. Drip irrigation is the controlled application of water at a very low flow over a prolonged period. It differs from conventional watering systems in that the soil is not supersaturated with water. When the rate of drip irrigation is adjusted correctly, there are no puddles of water, and no run-off. If puddling occurs, decrease the irrigation rate.

Many types of drip systems are available. Some use small water-releasing mechanisms called emitters, which drip a certain volume of water when a specific water pressure is supplied. Many of these systems are prepackaged, and allow little versatility or adaptation to the various sizes and shapes of gardens. Other systems currently available in garden centers can be adapted easily to almost any garden size and situation.

The most common has small holes pre-punched in plastic tubing at 12-inch intervals which allow the water to come out in small amounts. The tubes are placed along the plant rows so that root zones are moistened by the dripping water. To insure adequate moisture when the garden is planted, apply at least 2 inches of water to the planting zone before seeding or transplanting. This is referred to by farmers as pre-irrigation. Be sure rows are well firmed at the time of pre-irrigation so the water moves laterally in the soil as well as downward. Sprinkling the entire garden may be necessary to settle the soil enough for the drip irrigation water to move horizontally, and not go straight down the rows. This is needed especially in sandy gardens.

Once the drip irrigation system is in place and operating, how long it should be used for optimum plant growth varies with the plants grown and the season of the year, but a general recommendation is to operate the system 3 hours a day on alternating days, such as Monday, Wednesday, and Friday. When rainfall is adequate, it is not necessary to water for several days. [This article on fall gardening appeared in Texas EARTH-KIND Landscape and Gardening Guidelines, published by the Texas Cooperative Extension, 1998.]

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