Zucchini in Zone 10B — Florida

Zucchini brings incredible productivity to your Florida garden, delivering pounds of tender, versatile squash from just a few plants. In our 360-day growing season, you can enjoy multiple plantings throughout the year, with peak production during our cooler months when the intense summer heat won't stress these tender plants. The mild Florida winters let you grow zucchini when gardeners up north are dreaming of fresh vegetables.

Our extreme humidity and fungal disease pressure can challenge zucchini, but timing your plantings right makes all the difference. Plant during our "reversed" growing season - fall through spring - and you'll avoid the worst of summer's brutal heat while taking advantage of those perfect 70-80°F days that zucchini loves.

Starting zucchini seeds indoors isn't really necessary in Florida, but it can give you a head start on the season if you're eager for that first harvest. Start seeds late December through mid-January, about 3 weeks before you plan to transplant outside. Use seed trays with good drainage and keep them in a warm spot - your house temperature is perfect.

Bottom water your seed trays to prevent fungal issues that love our humid air. Once seedlings emerge, they'll need bright light from a sunny window or grow lights. Remember, our spring comes early compared to most of the country, so don't start too far ahead or you'll have leggy plants waiting around.

Since zucchini grows so fast once planted, most Florida gardeners skip the indoor start and direct sow instead. Only bother with indoor starting if you want to squeeze every possible day out of your growing season or if you're succession planting every few weeks.

If you started seeds indoors, transplant your zucchini outside from mid-January through early March, once nighttime temperatures consistently stay above 50°F. Even in Florida, our winter nights can dip surprisingly low, and zucchini is completely frost-tender - one cold snap will kill young plants.

Harden off your seedlings gradually over a week before transplanting. Start with just an hour or two outside in filtered sun, then increase exposure daily. Our Florida sun is intense even in winter, and indoor-grown plants need time to adjust. Space transplants 36-48 inches apart - these plants get huge and need room for good air circulation in our humid climate.

Plant on a calm day if possible, as winter winds can stress newly transplanted seedlings. Water deeply after planting and consider using row cover for the first week if cold weather threatens.

Direct sowing is the easiest way to grow zucchini in Florida, and you can plant from mid-January through late October - just avoid our peak summer months when it's too hot even for this heat-loving crop. Wait until soil temperatures reach at least 60°F; use a soil thermometer to be sure rather than guessing based on air temperature.

Prepare your planting area by working in plenty of compost to improve our sandy soil's water retention. Plant seeds 1 inch deep and space them 36-48 inches apart - closer spacing invites the fungal diseases that love our humidity. In summer plantings, wait until late afternoon to plant so seeds don't bake in the intense heat.

Zucchini germinates quickly in Florida's warmth, usually within 5-7 days. Keep the soil consistently moist but not waterlogged during germination. Once plants are established, they're remarkably fast growers in our climate - you'll be amazed how quickly they take off.

Zucchini needs consistent, deep watering in Florida's climate, especially during our hot, humid summers. These plants have high water needs and are not drought tolerant at all - inconsistent watering leads to blossom end rot and poor fruit development. Water at the base of plants, never overhead, since wet leaves plus our extreme humidity create perfect conditions for powdery mildew and other fungal diseases.

Use the finger test: stick your finger 2 inches into the soil near the plant base. If it's dry, it's time to water deeply. During our cooler months (fall through spring), this might be twice a week. In summer heat, you may need to water daily. Give plants about 1-2 inches of water per week, including rainfall - and remember, we typically get 50-65 inches of rain annually, mostly during summer.

Watch for signs of water stress: wilting in the heat of the day (normal), but also wilting in early morning or evening (not normal). Overwatered plants show yellowing leaves and may develop root rot in our poorly-draining sandy soils. Underwatered plants produce bitter fruit and are more susceptible to squash vine borers.

Mulch heavily around plants with organic matter like grass clippings or shredded leaves to conserve moisture and keep soil temperatures more consistent. This is crucial in Florida where soil can dry out quickly despite high humidity, and it helps prevent the wet-dry cycles that cause blossom end rot.

Your first zucchini harvest will start early March through late December, depending on when you planted. With our 50-day maturity period, you can time plantings perfectly - plant in mid-January for March harvest, or plant in September for November harvest. This gives you flexibility to avoid the worst of summer heat while still getting multiple crops per year.

Harvest zucchini when they're 6-8 inches long and still tender - the skin should give slightly to fingernail pressure but not be mushy. Check plants daily once they start producing because zucchini grows incredibly fast in Florida's warmth. A 6-inch zucchini can become a 12-inch baseball bat overnight, and oversized fruit is spongy and bitter with tough skin and large seeds.

Cut fruit from the plant with a sharp knife or pruning shears, leaving about an inch of stem attached. Never pull or twist fruit off as this can damage the plant. Regular harvesting encourages continued production - if you let fruit get oversized and go to seed, the plant will stop producing new flowers.

As late December approaches and our first frost threatens, harvest all remaining fruit regardless of size. Even small zucchini are edible, and you can use oversized ones for baking or composting. The plants won't survive any frost, but in many Florida years, you might not see frost until well into January.

Squash Vine Borers appear as sudden wilting of entire vines or sections, even when soil is moist. Look for small piles of sawdust-like frass at the base of stems - this is the telltale sign. If you slit open the stem, you'll find fat white grubs that have tunneled through and cut off the plant's water flow. These are larvae from clearwing moths that lay eggs at stem bases during our warm months. Wrap the base of stems with aluminum foil or use row covers when plants are young. Inject Bt (bacillus thuringiensis) into stems if caught early, or try succession planting to have backup plants ready.

Powdery Mildew shows up as white or gray powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die, reducing plant vigor significantly. This fungus thrives in our warm days and humid conditions - ironically, it actually prefers dry leaf surfaces unlike most fungi. Improve air circulation by proper spacing and removing lower leaves that touch the ground. Neem oil or potassium bicarbonate sprays help, but surprisingly, milk spray (1 part milk to 9 parts water) is very effective. Remove affected leaves immediately and dispose of them away from the garden.

Blossom End Rot appears as sunken, dark brown or black leathery patches on the bottom (blossom end) of fruit. This often affects your first fruits of the season and is heartbreaking for new gardeners. It's not a disease but a calcium deficiency caused by inconsistent watering - our sandy Florida soils drain quickly, creating drought-flood cycles that prevent calcium uptake. The fix is simple: water consistently and deeply. Mulch heavily to maintain even soil moisture, and avoid over-fertilizing with nitrogen which interferes with calcium absorption.

Florida's extreme humidity and wet summer rainfall create perfect conditions for fungal diseases on zucchini. Our sandy soils that drain quickly can also stress plants if you're not vigilant about watering. The key is consistent moisture without waterlogged conditions, plus good air circulation to combat the humidity.

Plant zucchini with corn and beans for a modified "three sisters" approach that works well in Florida - the corn provides some afternoon shade during intense summer sun, while beans fix nitrogen that feeds heavy-feeding zucchini. Radishes planted around the edges help deter squash bugs and make good use of space since they mature quickly. Mint planted nearby can help repel ants and some pests, though keep it contained as it spreads aggressively in our humid climate.

Avoid planting zucchini near potatoes, as both are susceptible to similar fungal diseases that spread easily in Florida's humid conditions. The potato family also competes heavily for nutrients that zucchini needs. Keep these plants in separate areas of your garden and rotate their locations each season to prevent disease buildup in the soil.