Nasturtium in Zone 8B — Florida

Nasturtiums are a fantastic addition to any Florida garden. Their peppery leaves and vibrant flowers add a unique flavor to salads and bring a splash of color to your landscape. Plus, they're surprisingly easy to grow, even with our reversed seasons and sandy soil.

Our Florida gardening calendar is different, and summer is the slow season. But with Nasturtiums, you can get a head start in spring or extend your growing season well into fall. Their adaptability makes them a rewarding choice for our 303-day growing season, especially since they don't mind the heat as much as some other cool-season crops.

Starting Nasturtiums indoors is possible, but honestly, it's usually not necessary here in Florida. They prefer to be direct-sown because they don't love having their roots disturbed. However, if you're itching to get a jump start, you can start seeds indoors from mid January through early February, about four weeks before our typical last frost.

Use seed trays with a good seed-starting mix, and keep them in a warm, bright location. Bottom watering is a good way to keep the soil evenly moist without encouraging fungal diseases. Remember, though, that our spring can be a bit of a rollercoaster, so be prepared to protect your seedlings if we get a late cold snap.

If you did start your Nasturtiums indoors, you can transplant them outdoors from late February through late March. Be sure to harden them off first. This means gradually exposing them to outdoor conditions for about a week.

When transplanting, space them about 10-12 inches apart. Keep an eye on the weather, as we can still get some unexpected temperature swings in late winter and early spring. A little frost cloth can go a long way in protecting your young plants.

Direct sowing is definitely the way to go with Nasturtiums in Florida. It's much easier on the plants, and they tend to take off quickly. You can direct sow from late February through early October, giving you plenty of time to enjoy these beauties.

Choose a spot with well-draining soil and full sun to part shade. Nasturtiums aren't too picky about soil, which is good news for our sandy soil. Sow the seeds about half an inch deep, and space them 10-12 inches apart. Keep the soil consistently moist until the seedlings emerge, which usually takes about a week or two.

Nasturtiums are pretty drought-tolerant, which is a bonus in Florida's sometimes unpredictable weather. They actually thrive in slightly poor, dry soil, so don't overdo it with the watering. Too much water or fertilizer will give you lots of leaves but fewer flowers.

During our hotter, drier spring months, check the soil moisture regularly. Stick your finger about two inches deep into the soil. If it feels dry, it's time to water. Aim for about an inch of water per week, especially during dry spells.

In the wet summer, you might not need to water at all, thanks to our regular rainfall. Water at the base of the plants rather than overhead to help prevent fungal diseases, which are common in our humid climate. If the leaves start to yellow, you might be overwatering. If they wilt and droop, they need more water. A light layer of pine straw mulch can help retain moisture without keeping the soil too soggy.

You can expect your first harvest of Nasturtium flowers and leaves around mid April through mid December, about 55 days after planting. The flowers are ready to harvest when they're fully open and brightly colored. The leaves can be harvested at any time.

To harvest, simply snip the flowers or leaves with scissors or your fingers. Be gentle to avoid damaging the plant. Regular harvesting encourages more flower production, so don't be shy about picking them.

As our first frost approaches around mid- December, harvest any remaining flowers and seed pods. The seed pods can be pickled and used like capers. Even if frost nips the plants, you can often get one last harvest of leaves before they completely fade.

Here in Florida, Nasturtiums can occasionally run into a few problems, but nothing too serious. The most common issues are aphids, cabbage caterpillars, and black fly.

Aphids

• What it looks like: Tiny green, black, or white bugs clustered on the stems and undersides of leaves. Leaves may be sticky or distorted.
• What causes it: Aphids are attracted to stressed plants, and our humid climate can sometimes create conditions that favor them.
• How to fix/prevent it: Nasturtiums actually act as a trap crop for aphids, drawing them away from other plants. You can also blast them off with a strong stream of water or use insecticidal soap if the infestation is heavy.

Cabbage Caterpillars

• What it looks like: Green caterpillars munching on leaves, leaving holes and ragged edges.
• What causes it: These caterpillars are the larvae of cabbage white butterflies, which are common in Florida gardens.
• How to fix/prevent it: Handpick the caterpillars off the plants or use Bacillus thuringiensis (Bt), a biological insecticide that is safe for humans and pets.

Black Fly

• What it looks like: Small black flies that suck sap from the plant.
• What causes it: Warm, humid conditions.
• How to fix/prevent it: Spray leaves with neem oil.

Florida Specific Challenges: Our hot, humid summers can make Nasturtiums more susceptible to fungal diseases. Make sure to provide good air circulation and avoid overhead watering. While nematodes can be a problem in our sandy soil, Nasturtiums are generally resistant to them, so that's one less thing to worry about.

Nasturtiums are great companions for many plants in the Florida garden. They are especially beneficial when planted near tomatoes, cucumbers, and squash because they help repel pests like squash bugs and aphids. The strong scent of Nasturtiums confuses these pests, making it harder for them to find their target plants.

They're also good companions for broccoli and cabbage, as they help deter cabbage moths. Avoid planting them near fennel, as fennel can inhibit the growth of many plants, including Nasturtiums. Nasturtiums play well with others, making them a valuable addition to any Florida vegetable garden.