Nasturtium in Zone 6B — Mid-Atlantic

Nasturtiums are a fantastic addition to any Mid-Atlantic garden. Their peppery leaves and bright flowers add a unique flavor to salads, and they're incredibly versatile in the kitchen. Plus, their cheerful blooms bring a burst of color to our gardens throughout the long growing season that our four seasons provide.

While we face challenges like humid summers and deer pressure, Nasturtiums are surprisingly resilient. With a growing season that stretches nearly 200 days, you have plenty of time to get these beauties established and enjoy their bounty.

Starting Nasturtium indoors is possible, but honestly, it's usually not necessary here in the Mid-Atlantic. They really do prefer to be direct-sown. However, if you're itching to get a jump start, you can begin seeds indoors from mid-March through early April, about four weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and keep them in a warm spot with plenty of light. Bottom watering is your friend here – set the tray in a shallow dish of water and let the soil soak it up to avoid disturbing the delicate seedlings. Our moderate spring weather means you can usually get away with direct sowing without much delay.

If you've started your Nasturtiums indoors, aim to transplant them outdoors from mid-April through mid-May. Before planting, be sure to harden them off by gradually exposing them to outdoor conditions for about a week.

Space them about 10-12 inches apart in a sunny spot. Keep an eye on the weather forecast – we can still get some unexpected chilly nights that time of year, so be prepared to cover them if needed.

Direct sowing is definitely the way to go with Nasturtiums. Wait until after the last expected frost, typically around mid-April, and you can continue sowing seeds through mid-August for a succession of blooms.

Choose a spot with full sun to part shade, and prepare the soil by loosening it up a bit. Nasturtiums aren't fussy – they actually thrive in slightly poor soil. Sow seeds about half an inch deep and 10-12 inches apart. These seeds need soil temperatures around 65-70°F to germinate well.

One of the best things about Nasturtiums is their low-maintenance watering needs. They're surprisingly drought-tolerant, which is great for our Mid-Atlantic summers. Remember, too much water encourages leaf growth at the expense of flowers.

During the spring and fall, with our regular rainfall, you likely won't need to water them much at all unless we're experiencing a dry spell. In the heat of summer, check the soil moisture with the "finger test" – stick your finger about 2 inches deep into the soil. If it feels dry, give them a good soaking, aiming for about an inch of water per week. Water at the base of the plants to avoid wetting the foliage, as our humid summers can make them susceptible to fungal diseases.

Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. A light layer of mulch can help retain moisture and suppress weeds, but don't overdo it – good airflow is important in our humid climate.

You can expect your first Nasturtium harvest starting around mid-June, and they'll continue to produce right up until late October. Both the flowers and leaves are edible, so harvest them as needed.

Pick the flowers when they're fully open for the best flavor and visual appeal. To harvest, simply snip the stem just below the flower or leaf. Regular harvesting encourages the plant to produce even more blooms. As the weather cools in late October and the first frost approaches, harvest any remaining flowers and leaves. You can even pickle the seed pods for a caper-like treat.

Here are some common problems you might encounter with Nasturtiums in the Mid-Atlantic:

Aphids

• What it looks like: Clusters of tiny green, black, or brown insects on stems and leaves. Leaves may be sticky or distorted.
• What causes it: Aphids are attracted to stressed plants and can multiply quickly in our humid conditions.
• How to fix/prevent it: Nasturtiums can actually be used as a trap crop to draw aphids away from other plants. If infestations are heavy, spray with a strong jet of water or use insecticidal soap.

Cabbage Caterpillars

• What it looks like: Holes in leaves, often with green droppings nearby. You might spot the caterpillars themselves, which are green and blend in well with the foliage.
• What causes it: These caterpillars are the larvae of cabbage white butterflies, which are common in our region.
• How to fix/prevent it: Handpick the caterpillars off the plants. You can also use floating row covers to prevent the butterflies from laying eggs on your Nasturtiums.

Black Fly

• What it looks like: Similar to aphids, you'll find clusters of small, black flies on the stems and undersides of the leaves.
• What causes it: Black fly thrive in warm, humid weather and can quickly weaken plants by sucking their sap.
• How to fix/prevent it: Encourage beneficial insects like ladybugs, which prey on black fly. Insecticidal soap can also be effective.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers, combined with high humidity and regular rainfall, can create ideal conditions for pests and diseases. Good air circulation and careful watering practices are key to keeping your Nasturtiums healthy.

Nasturtiums make excellent companions for several plants in the Mid-Atlantic garden. They're particularly beneficial near tomatoes, cucumbers, and squash, as their strong scent can help repel pests like squash bugs and aphids.

They also do well planted near broccoli and cabbage, acting as a trap crop for cabbage white butterflies. Avoid planting them near fennel, as it can inhibit their growth.