What tips do you have for North Florida Gardeners?
Don't plant too early because the weather is so nice. Get your soil tested now so you can get your gardens fertilized correctly. You will save money and have a great garden if you know what you need to add to your soil. Be sure to follow the publication from the ag center on how to gather your soil for a test. Don't just do it willy-nilly. That won't be accurate.
Plant pisum sativum cultivars now in 9a (inoculate, it's worth it!). Sow brassica and mustard family seeds. If you don't have hairy indigo for a cover crop, send me an email, I have ten acres of plants in seed.
I am assuming this is intended for newcomers, mostly from places up North that have a different climate. With that in mind:
Overview: North Florida is kind of a "between" area. This area has a distinct winter with frosts and freezes every year, so true tropicals can't survive outdoors here. But the winter is too short and mild (and the summers too long, hot, and humid) for many deciduous plants. Nevertheless, there are many beautiful plants that thrive here and many different landscape styles are possible. Subtropical plants and hardy palms can be used to obtain a "tropical" look, or well-adapted deciduous shrubs and trees can be used to provide beautiful fall foliage displays.
Don't trust the big box stores to know what works well in this area. They often sell plants that can't take the heat/humidity or need more chill hours than this area receives. They also have a bad habit of selling citrus without clearly marking how much cold it can survive. (Only the most hardy types of citrus can be grown in-ground in North Florida.) Find a good LOCAL nursery or do your own research before buying plants.
A great place to do research is the University of Florida's Institute of Food and Agricultural Sciences (IFAS) website. It's a treasure trove of information for the home gardener. Recommended plant varieties, planting dates, care information, and troubleshooting information are all provided.
Soil: The "soil" in North Florida is mostly sandy, usually acid, and very low in nutrients and organic matter. It drains very quickly after rains, and the upper layers of the soil can be bone dry only a few days after heavy rainfall. The soil also tends to be infested with root-knot nematodes, which will weaken or kill plants that are not resistant.
It is possible to amend the soil by adding lots of organic matter, but the heat and heavy rainfall will quickly break down and leach out the organic matter. So, amending the soil has to be an ongoing process. For large areas, that can be a considerable effort and expense. Also, amending the soil will not eliminate the nematodes (there is no effective nematode-killer licensed for home gardeners). It is less effort and expense to plant nematode-resistant plants that are adapted to the soil and climate. Plants that require a fertile soil can be used as accents in containers or small beds where it's practical to maintain an organic soil. Nematode-susceptible plants can be grown in containers with no direct contact between the container soil and the ground.
Vegetable Gardening: In North Florida's it's easy to harvest fresh food from the vegetable garden 365 days a year, without the use of a greenhouse or even a cold frame. The only "tricks" are learning how to deal with our poor sandy soil and learning the correct planting times for each vegetable. Generally speaking, vegetables that can tolerate some frost are grown from fall through spring, and vegetables that are frost-tender are grown from March through November.
However, learning the correct planting dates for each vegetable is important. North Florida can have long periods of mild weather in the winter and early spring, then a sudden freeze. It's easy to be fooled into planting tender vegetables too early and then lose everything to a freeze. Also, some of the cool-season vegetables can be grown all through the winter, while others can only be grown in fall or spring. IFAS has a vegetable gardening guide (http://edis.ifas.ufl.edu/vh021) that includes planting times, recommended varieties for each vegetable.
Most vegetables will not provide a good harvest if they are simply planted in the native soil. Fertilizers can provide nutrients, but they don't improve the water-holding capacity of the soil. It is helpful to heavily amend the soil with organic matter and compost, or plant vegetables in containers or raised beds filled with good soil. Mulching is very beneficial for many vegetables. Promptly removing diseased plants and rotating crops (to keep nematodes and diseases from building up in the soil) are critical.
Supplemental irrigation is usually necessary for vegetables, since North Florida tends to have long dry periods in fall through spring. While rains are usually frequent in summer, extended dry spells do occur. Drip irrigation or micro-irrigation are recommended, both to conserve water and to prevent wetting the foliage.
Even with good care, diseases and insects can cause problems, especially in the summer. Prevention is usually easier than curing when it comes to fungal diseases. The IFAS website is a good place to research potential problems and develop a strategy for preventing or managing them.
July and August are difficult months in the vegetable garden. Even experienced Florida gardeners often lose plants (especially cucumbers, tomatoes, and squash) in these months. Don't despair: the growing season is long enough to replant these crops for a fall harvest. (See IFAS for recommended planting dates.) The fall garden is often very productive and enjoyable, with pleasant weather, fewer bugs, and less disease pressure.
Edible Landscaping and Fruits: By planting a selection of fruit trees, bushes and plants, it's possible to harvest fresh fruit every season of the year. Just a few examples of North Florida fruits are strawberries and loquats in early spring, blueberries in late spring, apples, peaches, plums, grapes and blackberries in late spring and early summer, figs, pears, and pomegranates in summer and fall, persimmons in late fall, and citrus for the holiday season!
However, selecting the right varieties of fruits is extremely important. For example, most of the apples, peaches, pears, and plums sold in grocery stores will not thrive here because this area does not get enough winter chill. Low-chill varieties are necessary to be sure to get a crop. Even fruits that don't require winter chill need to be resistant or tolerant to certain diseases. Only the most cold-hardy citrus and subtropical fruits can survive North Florida winters.
Again, the IFAS website or a good LOCAL nursery can help in selecting the right varieties to thrive here. Also check with Just Fruits and Exotics (http://www.justfruitsandexotics.com/index.html) for recommendations, or talk to neighbors with fruit trees. How long they have had their tree(s)? Do they get a consistent crop? How do they care for them?
I am not claiming by any stretch to be an expert - most of what I have learned is from years of killing plants. :-o But I felt that North Florida needed an overview. Feel free to use any of this or none of it.
If a real expert wants to post and tell me I am wrong about something, I am cool with that, too: at least I'll learn something that way.
Here is a link that might be useful: UF IFAS - Florida Garden Information Articles