Nasturtium in Zone 10B — Florida

Nasturtiums are a fantastic addition to any Florida garden. Their peppery leaves and vibrant flowers add a unique zest to salads and other dishes. Plus, they're incredibly easy to grow and will reward you with a long season of edible beauty.

While our summers can be tough on many plants, nasturtiums thrive during our cooler months, giving you a chance to enjoy fresh harvests when other crops are slowing down. With our nearly year-round growing season, you can enjoy these beauties for most of the year with the right timing.

While nasturtiums prefer to be direct-sown, you *can* start them indoors if you want a head start, especially if you're aiming for an early spring bloom. Starting seeds indoors in early to late December gives you about 4 weeks to get them ready for transplanting after any threat of frost has passed.

Use seed trays with a good seed-starting mix and keep them in a warm, well-lit area. Bottom watering is your friend here – it helps prevent damping-off, a common issue in our humid climate. Remember, Florida's "spring" is reversed – we're starting these when other gardeners are winding down!

Transplanting nasturtiums outdoors should be done in mid January through early February. Before you plant them, it's crucial to harden them off. This means gradually exposing them to outdoor conditions for about a week to prevent transplant shock.

Choose a spot with well-draining soil and space the plants 10-12 inches apart. Keep an eye on the weather – those early weeks can still bring unexpected temperature swings, so be ready to cover them if needed.

Direct sowing is the way to go with nasturtiums. They really don't like having their roots disturbed, so planting them straight into the ground is ideal. You can direct sow from mid January through late October, giving you a long window of opportunity.

Prepare your soil by loosening it up and ensuring good drainage. Nasturtiums aren't picky about soil – in fact, they prefer it on the poorer side. Sow seeds about ½ inch deep, spacing them 10-12 inches apart. Keep the soil consistently moist until they germinate.

Nasturtiums are pretty low-maintenance when it comes to watering, which is great for Florida gardeners. They actually thrive in slightly dry conditions, and overwatering can lead to more foliage than flowers. Remember, less is more with these beauties.

During our drier months (late fall through spring), check the soil moisture by sticking your finger about 2 inches deep. If it feels dry, give them a good watering, aiming for about 1 inch of water per week. Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our humid climate. In the wet summer, they may need no additional watering at all.

In the summer, our frequent rainfall usually takes care of their watering needs. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. Mulching around the base of the plants can help retain moisture in the soil and prevent weeds.

You can expect your first harvest of nasturtium flowers and leaves starting in early March through late December, about 55 days after planting. The flowers are ready to pick when they are fully open and vibrantly colored. The leaves can be harvested at any time.

When harvesting, use scissors or your fingers to gently snip off the flowers or leaves, being careful not to damage the rest of the plant. Regular harvesting encourages more blooms and keeps the plant producing.

As late December approaches and our first frost is on the horizon, harvest any remaining flowers and leaves to enjoy. You can also collect the seed pods for pickling, offering a caper-like flavor to your dishes.

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

Aphids

• What it looks like: Small, soft-bodied insects clustered on stems and leaves, often accompanied by sticky honeydew.
• What causes it: Aphids thrive in warm, humid conditions, making them a common pest in Florida.
• How to fix/prevent it: Nasturtiums are actually great as a trap crop for aphids, drawing them away from other plants. If infestations get too heavy, spray plants with a strong stream of water or use insecticidal soap.

Cabbage Caterpillars

• What it looks like: Green caterpillars that chew holes in leaves, leaving behind droppings.
• What causes it: These caterpillars are the larvae of cabbage white butterflies, which are common in Florida gardens.
• How to fix/prevent it: Handpick caterpillars off plants or use Bacillus thuringiensis (Bt), a natural bacteria that targets caterpillars.

Black Fly

• What it looks like: Tiny black flies clustered on new growth, sucking sap from the plant.
• What causes it: Black fly infestations are more likely in humid environments.
• How to fix/prevent it: Spray plants with insecticidal soap or neem oil. Ensure good air circulation around plants to deter black flies.

Florida Specific Challenges: Our hot, humid summers can create the perfect environment for fungal diseases to take hold on nasturtiums. Also, be mindful of nematodes in the soil. Though nasturtiums aren't particularly susceptible, a heavy infestation in your garden can still impact their overall health.

Nasturtiums make excellent companions for many plants in your Florida garden. They attract beneficial insects and can even act as a trap crop, drawing pests away from your more vulnerable veggies.

Good companions include tomatoes, cucumbers, and squash. Nasturtiums help deter pests like aphids and squash bugs, protecting these crops. They also work well with broccoli and cabbage, as they can help repel cabbage moths. Avoid planting them near fennel, as it can inhibit their growth.