Mint in Zone 9B — Florida

Mint is a fantastic herb to grow in Florida. The fresh, vibrant flavor elevates everything from mojitos to summer salads, and you can even use it to make refreshing iced tea on those extra-hot days. Plus, there's a real satisfaction in snipping your own homegrown mint for recipes or garnishes.

Our Florida gardening calendar is different, and summer is the slow season. But with the right timing, you can enjoy a good mint harvest during our milder months. The 344-day growing season gives you plenty of opportunities to make it work.

Starting mint from seed indoors isn't the most common approach here in Florida, since you can easily propagate it from cuttings or divisions. But if you're after a specific variety, starting indoors gives you more control. Begin in mid-November through early December, about eight weeks before you want to transplant.

Use seed trays with a good seed-starting mix, and provide warmth and light – a simple grow light works wonders. Water from the bottom to prevent damping-off, which can be a problem in our humid climate. Remember, our spring is reversed, so you're starting these seeds when most gardeners up north are winding down!

Transplant your mint outdoors in mid-January through mid-February. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Florida sunshine and humidity.

Space your plants about 18-24 inches apart. Mint spreads aggressively, so consider planting it in containers to keep it from taking over your garden beds. You can also buy starts from a local nursery or get divisions from another gardener. Keep an eye on the weather in January and February. Even though we’re past our typical frost date, we can still get some chilly nights.

Mint loves consistently moist soil, which can be a bit of a balancing act in Florida's climate. During the spring growing season (late March through early May), water deeply whenever the top two inches of soil feel dry to the touch – that's the "finger test." You'll probably need to water about 1-2 inches per week, depending on rainfall.

In the summer, when the heat and humidity are at their peak, you might think you need to water more, but be careful not to overdo it. Our wet-summer rainfall can easily lead to soggy soil. Water at the base of the plant rather than overhead to minimize fungal diseases.

Signs of underwatering include wilting leaves, while yellowing leaves often indicate overwatering. Mulching around your mint with pine straw or wood chips can help retain moisture in the soil and suppress weeds, which is always a plus.

Pruning mint is more about controlling its spread than encouraging growth. This herb is vigorous, and it will happily take over your garden if you let it. Throughout the growing season, cut back stems aggressively to keep the plant in bounds and encourage bushier growth.

Regularly harvest entire stems, as this also helps control the spread. Pinch off any flower buds you see to encourage continued leaf production, as the leaves are most flavorful before flowering. As our first frost approaches in late December, you can give your mint a final haircut to tidy it up for the cooler months.

You can expect your first mint harvest from late March through early May, about 60 days after transplanting. The best time to harvest is before the plant starts to flower, as the leaves are most flavorful then. Look for healthy, vibrant green leaves and stems.

To harvest, simply snip off stems with scissors or pruning shears. Avoid damaging the main plant by cutting cleanly above a leaf node. Regular harvesting encourages continued production, so don't be shy about using your mint! As our first frost approaches in late December, you can harvest any remaining leaves and dry or freeze them for later use.

Here are some common issues you might encounter growing mint in Florida:

Rust

• What it looks like: Rusty orange, yellow, or brown pustules on leaves and stems, mostly on undersides. Leaves yellow and drop prematurely.
• What causes it: Rust fungi thrive in our warm, humid conditions, especially when leaves stay wet.
• How to fix/prevent it: Remove affected leaves promptly. Avoid overhead watering. Improve air circulation by spacing plants adequately. Apply sulfur or copper fungicide if needed, but try to avoid working among wet plants to prevent further spread. Crop rotation can also help.

Spider Mites

• What it looks like: Fine stippling on leaves (tiny white dots). Fine webbing on leaf undersides and between stems. Leaves turn bronze or yellow.
• What causes it: These tiny pests thrive in hot, dry conditions. Populations explode when plants are stressed by drought.
• How to fix/prevent it: A strong water spray (daily for a week) is often the best treatment. Increase humidity around plants. Neem oil or insecticidal soap can also help. You can also release predatory mites (Phytoseiulus persimilis) to control spider mite populations. Avoid broad-spectrum pesticides that kill beneficial predators.

Invasive Spreading

• What it looks like: Mint popping up everywhere you don't want it.
• What causes it: Mint spreads via underground rhizomes, and it's very good at it.
• How to fix/prevent it: The easiest fix is to plant mint in containers to restrict its spread. You can also sink a barrier (like plastic edging) around the planting area, burying it deep enough to prevent the rhizomes from escaping.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is surprisingly effective.

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall create ideal conditions for fungal diseases like rust and powdery mildew. Monitor your mint regularly and take action quickly to prevent problems from getting out of control.

Mint is a great companion plant for tomatoes and peppers because its strong scent can help deter pests like aphids and flea beetles. It also benefits cabbage and broccoli by repelling cabbage moths. The aroma confuses the pests and protects the plants.

Avoid planting mint near parsley or chamomile. Parsley doesn't like mint's strong scent and can suffer stunted growth. Chamomile can compete with mint for resources and may also attract pests that bother mint.