1. Don't plant cool weather crops in the spring.
There are many early spring crops that just don't have a long enough growing period before the hot weather sets in if they are planted in the fall. My suggestion is to put out cool weather plants such as broccoli, cauliflower, carrots, cabbage, brussel sprouts, lettuce, etc. into the vegetable garden in September so that they can mature and be harvested in early winter (December- January). There is just no way that you will be able to keep these plants from bolting of wilting before harvesting in June if you garden in the deep south. Besides, now that you can plant all of these vegetables in the fall, think of all of the garden space that frees up in the spring!
Most garden books will tell you to plant new fruit trees or perennial fruit, vegetable, and herb plants in the spring so that they can be well established before their first cold winter. In the deep south we have a bigger threat to new plants- the summer heat! Plant citrus trees, blackberry and blueberry bushes, asparagus, rosemary, etc. in the fall so that they have all winter to establish before the blistering summer comes.
Many plants will be marked as needing full sun, but full sun really means 8 hours of sunlight. Even your full sun plants will find it difficult to hold their leaves up if you have them in direct summer sun for 12 hours. Move plants into areas where they will get part shade if you live in a hot climate, and plants requiring part shade can easily get away with almost full shade. Most leafy greens will thank you for the shady spot in the garden and will be slower to bolt. Also, cool season herbs can be treated as perennials if given shade in the summer.
4. Get creative with watering solutions.
Plants in hot climates need more to drink. Thankfully in Louisiana we also have a tropical climate with a lot of rain and humidity. Humid climate areas should water their plants in the morning so that the water evaporates off of the leaves and keeps diseases from spreading as easily. Hot and dry climates, on the other hand, should be watered in the evening so that less of the water evaporates during the sunlight throughout the day. Watering can be kept to a minimum if you use drip irrigation systems connected to rain barrels (or the cheaper version, 2 liter bottles flipped upside down in the dirt with a small hole in the top). Whatever the method, make sure your plants stay well hydrated to make it through the heat wave.
5. Plan your winter break in July and August.
In the same way that many climates are too cold to plant in the most extreme part of the season, the same is true with heat in the south. Some plants thrive in the long, hot summer days, such as eggplant, peppers, okra, and some tomatoes, but most plants just can't handle the heat. Some plants, such as beans, will actually become infertile past 90 degrees F and no longer produce fruit. My lowest garden production isn't in January of February, but in July and August. Plan to take a break during these months and plan for you fall garden, starting seeds inside in the same way that gardeners up north would do in the winter. Besides, if it's too hot for the plants, it's too hot for me...
6. Start your spring garden seeds super early!
While other areas are waiting for their soil to be "workable", ours plants haven't even stopped growing. I have found that the perfect time to start my new seeds indoors is new year's day. This sounds crazy early for most places, but in the deep south, tomatoes, peppers, eggplant, and more can be started in January, followed by watermelon, cantaloupe, and others in February. One year I was able to start all of my seeds outside in January with no problems, but you will get much better germination results if you start your plants indoors under lights for the first 6 weeks or so.
7. Direct sow more plants than usual.
Plants will grow stronger, healthier, and more hardy if they are direct seeded than if they are started indoors. Many places with short growing seasons don't have the luxury of direct seeding, though. However, since the soil temperature is what determines success in germination, there are a lot plants that will start just fine and develop better when direct seeded in southern vegetable gardens. Some of these plants include peas, beans, cucumbers, squash, zucchini, lettuce, kale, mustard greens, collards, and many more. Do a few tests starting some seeds indoors and then direct seeding more seed at the same time that you put your transplants into the ground. You will be surprised how fast the new seeds catch up to and even surpass your pre-started plants.
8. Plant long season crops in the fall.
There are many crops that will take up to 6 months or more to fully develop. Some of these include garlic, onions, and potatoes. These will have a much longer period to develop before the heat takes them out if they are planted in the fall instead of the traditional spring timeline. Don't worry, they will overwinter just fine! Besides, it leaves more room in your spring garden for other plants!
There are many plants that are considered annuals in many areas that will act as perennials in the deep south. Some of these include green onions, collards, kale, and many varieties of herbs such as oregano, sage, and parsley. Other plants, while not perennials in the sense that you plant them once and they grow forevermore, will still grow year round. Some plants that you can plant at almost any time of year (except the extreme summer) include lettuce, carrots, arugula, mustard, beets, turnips, radishes, spinach, and many types of beans. I am continually surprised when I have some extra seeds and an open spot in the garden and decide to give it a shot even though it doesn't match the seed packet timing at all, and it turns out to be a wonderful harvest! You won't know unless you try :)
10. Be prepared for bugs.
The longer the growing season is and the more mild the winters, the more things survive- "things" being both plants and their pests. Bugs will abound in the southern garden, and the farther into the growing season you are, the worse it gets. This is another reason why you should plant as many of your vegetables as possible in September for a fall garden as the cooler weather will cut down on the pests. Each garden pest brings its own set of challenges, but a southern gardener must be determined and vigilant to stay on top of the many bugs that will come to visit.
We have such a long growing season in the south that many vegetables can be planted twice if you plan it right. You can start any of the following in both spring and fall: tomatoes, cauliflower, broccoli, beans, summer squash, zucchini, kale, lettuce, carrots, beets, turnips, radishes, arugula, cabbage, and much more. I wouldn't recommend planting everything twice, as they will really complicate your crop rotation plans and limit your space. However, if there is a certain vegetable that you just love (for me, bush beans!), then go ahead- plant it twice!