March 24, 2009

Spring Vegetable Gardening

Cindy Peacock, Horticulturist, Pinellas County Extension

If you have not planted your spring vegetables yet you still have time. The University of Florida/IFAS Extension Vegetable Gardening Guide for Florida can be accessed at: . In this guide there is a list of the spring vegetables that can be planted at this time.

To make room for your spring vegetable plants you will need to take out those vegetable plants that have stopped producing, that are sick with diseases like powdery mildew, that are loosing leaves, or are cold damaged. Some of your fall plants may still look good and are producing, so keep them in as long as you can. The broccoli will continue to give you small florets until the temperature gets too hot. Greens will slow down the hotter it gets. Tomatoes will continue to produce too, although when the night temperatures stay above 70 degrees, you will have fewer tomatoes. If your tomato plant is not producing, you can start over with a new plant. The small cherry tomatoes are a good choice for warmer temperatures since they will set fruit better in the heat. For more information about Tomatoes in the Florida garden, access the University of Florida/IFAS Extension fact sheet:

Once you clear out those old plants you will have room to add more organic matter such as compost. You can also add more top soil. Be sure to mix it in with the soil.

Choose seeds of those vegetable that you like. Use the spring vegetable list.
Warm season vegetables such as beans, cucumbers, eggplant, southern peas, peppers, okra, summer and crookneck squashes can all still be planted. Carrots and radishes can be planted through March. This is a good time for cantaloupe and watermelon too. But remember, these two plants require a lot of space, so give them plenty of space to spread out. If you put in five seeds of cantaloupe or watermelon you should leave a 6 ft. by 6 ft. space for them to grow.

Be sure not to plant the seeds too deep, usually no deeper in the soil than the size of the seed. Keep them moist until you see them start to sprout, then cut back on the water. Your vegetable garden needs water two to three times a week. If we have rainfall, then you can skip that watering day.
Starter plants that you purchase can also be used. When planting tomatoes, bury the plant up to the first set of leaves.

Here are some things to look for in your garden. As the temperatures fluctuate, vegetables can develop problems due to environmental factors. Powdery mildew, a white powdery film that covers the leaves, is a disease that we tend to see on our vegetables in the spring. To help control this disease, you can use one tablespoon of baking soda and one tablespoon of a paraffinic oil (horticultural oil) per one gallon of water. Mix this well and spray on the leaves every five to seven days. This fungicide was developed at Cornell University.

As the plants get new tender growth you will see an increase of insects. Not all insects are bad. We have insects that help us keep the harmful insects away. It is helpful to know the difference. Look at the University of Florida /IFAS Extension fact sheets of harmful vegetable garden insects: and
Now review the fact sheets of beneficial insects:,, and You will want to look for these beneficial insects any time you see the harmful insects.

Aphids and whiteflies can be a big problem with the tender new growth of your vegetables. These insects are tiny soft bodied insects that suck the juices from the plants. They also excrete a sugary substance that a black sooty mold uses for food. Sometimes you see the mold before you see the insects. These insects can be sprayed with a light horticultural oil. Before you spray look around for those beneficial insects. If you see lady bugs, or lacewings, or their larva, they will eat these insects for you. Check back in a couple of days to see if there are fewer of the aphids and whiteflies. If not, then you can use a horticultural oil, or insecticidal soap.

Wasps are good insects, too. They help to control caterpillars by feeding them to their young. Caterpillars can be a big problem in your vegetable patch. Look for them on cucumber and squash leaves, near the soil around peppers, beans, and eggplant, and those really large green hornworms on your tomato plant.
By picking them off and putting them in a sealed baggie, or in a can of soapy water, you will not have to use pesticides. If you choose not to pick them off, you can use a product containing Bacillus thuringiensis (Bt), such as Thuricide or Dipel. These insecticides will kill the caterpillars, but will not harm pets or humans.

Over-watering can cause problems. Too much water can promote the development of fungal diseases that might cause plants to rot, or become diseased. Once your vegetable garden is established, watering two to three times a week is all that is needed. It is best to water in the early morning.

Tomato leaf curl virus is a disease that we have seen frequently. The new growth is shriveled and the leaf veins are yellow. Whitefly insects spread this virus. Once a vegetable plant has a virus it should be taken out because there is no cure. For more information about this virus go to University of Florida/IFAS Extension fact sheet:

Nematodes are microscopic worms that feed on the roots of vegetable plants (Root Knot, Sting Nematodes). Raised beds and containers that have organic matter (compost) added will help lessen nematode problems. Using clear plastic over the beds to solarize the soil during the summer will help sterilize the soil to keep the population of nematodes down. The University of Florida/IFAS fact sheet for managing nematodes can be accessed at:

There are many other fact sheets available from the University of Florida/IFAS Extension that will help you with your vegetable gardening, see this topic area:

For problems that you need diagnosed, bring your sick leaves, stems, flowers, fruits and insects into the Lawn and Garden Help Desk at the Extension office in Largo and we can identify the problem and suggest treatment.

Vegetable gardening is a learning experience that is worth the work involved. Don’t let the insects and diseases scare you. We have plenty of the good insects to help control pest insects, and using the right cultural practices can control diseases. Just be patient and learn as you go. You will be amazed how good your own grown vegetables will taste.


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