Lobelia in Zone 10A — Florida

Lobelia is worth adding to your Florida garden for its profuse blooms and delicate texture. The masses of tiny blue flowers add a cooling effect during our warmer months. While it's not edible, it's a beautiful addition to borders and containers.

Growing Lobelia in Florida does come with challenges, like our intense summer heat and humidity. But by starting seeds at the right time and providing proper care, you can enjoy these beauties throughout our long, 355-day growing season. We just have to remember that our Florida gardening calendar is different from the rest of the country.

Starting Lobelia from seed indoors is an option, but honestly, with their tiny seeds and slow growth, you might find it easier to buy starts from a local nursery. If you *do* want to try starting them yourself, begin in early to late November, about 10 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and keep them consistently moist. Bottom watering is ideal to prevent disturbing the tiny seeds. Provide warmth and plenty of light. Remember, our spring is reversed here, so you're starting these as we move into our cooler months.

Transplant your Lobelia seedlings outdoors in late January through late February. Before you put them in the ground, harden them off for about a week by gradually exposing them to outdoor conditions.

Space them 4-6 inches apart in well-draining soil. Even though it's winter, keep an eye on the weather. We can still get some warm spells, so make sure they get enough water. Honestly, consider buying starts. They are very slow to grow and the seeds are tiny.

Lobelia needs consistent moisture to thrive, especially in our Florida climate. While we have a wet summer, our winters can be surprisingly dry. Aim to keep the soil consistently moist, but not soggy.

During the cooler months, check the soil moisture using the "finger test"—stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. You might need to water a couple of times a week, providing about an inch of water each time. In the rainy season, you may not need to water at all. Avoid overhead watering as our very-high humidity can lead to fungal diseases. Water at the base of the plant.

Signs of underwatering include wilting and dry, crispy leaves. Overwatering can lead to yellowing leaves and root rot. Adding a layer of mulch around your plants helps retain moisture and suppress weeds. Pine straw or wood chips work well in our sandy soil.

Lobelia requires minimal pruning. The main thing you'll want to do is shear them back by about half when flowering slows down in midsummer. This encourages fresh growth and more blooms as the weather cools down in the fall.

Just use a pair of scissors or pruning shears to trim back the stems and foliage. Don't be afraid to cut them back fairly hard – they're resilient. As we approach late December and the first frost, you can let them be. They may die back, but often return in the spring.

Lobelia isn't really a "harvest" crop in the traditional sense. You're growing it for its beautiful blooms, not for food. You can expect the first flush of flowers in late March through mid May, about 65 days after transplanting.

The best way to "harvest" Lobelia is to simply enjoy the masses of tiny blue flowers in your garden. Deadheading spent blooms can encourage continued production, but it's not essential. You can simply let them flower and enjoy the show.

As the first frost approaches in late December, you can let the plants go to seed if you want to try collecting seeds for next year. Otherwise, just enjoy the last of the blooms and let the plants rest.

Here are some common problems you might encounter with Lobelia in Florida:

Dies back in extreme heat

• What it looks like: The plant stops growing, the leaves turn brown and crispy, and it may appear to be dying.
• What causes it: Our intense summer heat can be too much for Lobelia, especially when combined with high humidity.
• How to fix/prevent it: Provide afternoon shade, especially during the hottest part of the day. Ensure adequate watering, but avoid overwatering. Mulch around the base of the plant to help retain moisture.

Damping off from overwatering

• What it looks like: Seedlings suddenly collapse and die, often with a fuzzy white or gray mold on the soil surface.
• What causes it: Overwatering and poor drainage create a breeding ground for fungal diseases that attack young seedlings. Our high humidity exacerbates this issue.
• How to fix/prevent it: Use a well-draining seed-starting mix. Water from the bottom to avoid wetting the foliage. Provide good air circulation. Don't overwater!

Slugs

• What it looks like: Irregular holes in leaves, especially low-growing plants. Silvery slime trails on leaves and soil. Damage worse at night and in wet weather.
• What causes it: Gastropods that feed at night in moist conditions. Hide under mulch, boards, and debris during the day.
• How to fix/prevent it: Beer traps (shallow dish of beer sunk into soil). Iron phosphate bait (pet-safe). Remove hiding spots. Water in morning so soil surface dries by evening. Copper tape around beds. Diatomaceous earth around plants.

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall can create a challenging environment for Lobelia. Choosing the right location, providing adequate drainage, and being vigilant about watering and pest control are key to success.

Lobelia makes a great companion plant for several vegetables in your Florida garden. Plant them near tomatoes and peppers to attract pollinators, which will help increase your fruit set. They also work well alongside lettuce, providing a bit of shade that can help prevent bolting in the warmer months.

Avoid planting them near root crops like carrots and radishes, as they can compete for nutrients in our already sandy soil.