Nasturtium in Zone 5A — Northeast

Nasturtiums are a fantastic addition to any Northeast garden. Their peppery leaves and bright flowers add a unique flavor to salads, and they're incredibly versatile in the kitchen. Plus, the visual pop of color is a welcome sight during our short but sweet summers.

Our growing season here in Zone 5A is a bit of a sprint, lasting only about 153 days. We have to watch out for late spring frosts and early fall freezes. But don't worry, with a little planning, you can easily get a bountiful harvest of these beauties.

While nasturtiums prefer direct sowing, you *can* start them indoors if you're eager to get a head start, especially if you're aiming for blooms as early as possible. Start your seeds indoors from early to late April, about four weeks before the last expected frost.

Use seed trays or small pots filled with a well-draining seed-starting mix. Keep them warm and provide plenty of light, either with a sunny windowsill or a grow light. Bottom watering is a great way to keep the soil moist without overwatering, which these plants dislike. Keep in mind that our late spring means you'll need to be extra careful hardening them off before transplanting.

Transplant your nasturtium seedlings outdoors from early May through early June, once the danger of frost has passed. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week.

Choose a sunny spot with well-drained soil, spacing the plants about 10-12 inches apart. Be gentle when transplanting, as nasturtiums don't love having their roots disturbed. Keep an eye on the weather forecast; a late frost can still sneak in during early May, so be prepared to cover your seedlings if needed.

Direct sowing is the preferred method for nasturtiums, as they resent transplanting. Wait until after the last expected frost, typically from early May through late July, to sow your seeds directly into the garden.

Choose a sunny spot with well-drained soil. Nasturtiums aren't picky and actually thrive in poorer soil, so don't worry about amending it too much. Sow the seeds about ½ inch deep and 10-12 inches apart. Keep the soil consistently moist until the seedlings emerge, which usually takes about a week or two.

Nasturtiums are remarkably drought-tolerant and thrive on neglect, making them perfect for the sometimes unpredictable Northeast weather. The key is to avoid overwatering, as this can lead to more foliage and fewer flowers.

During the spring, when rainfall is generally consistent, you likely won't need to water them much at all unless we're experiencing a particularly dry spell. Once summer hits, check the soil moisture by sticking your finger about two inches deep. If it feels dry, give them a good soak, aiming for about an inch of water per week.

Water at the base of the plants to avoid wetting the leaves, which can encourage fungal diseases in our moderate-to-humid summers. Yellowing leaves can be a sign of overwatering, while wilting leaves indicate they need a drink. A light layer of mulch can help retain moisture in the soil, especially during the hotter months, but avoid thick layers that can trap too much moisture.

You can expect your first harvest of nasturtium flowers and leaves starting in early July and continuing through early October, about 55 days after planting. Look for flowers that are fully open and vibrantly colored; these will have the best flavor.

Harvest leaves and flowers by snipping them off with scissors or gently pinching them off with your fingers. Regular harvesting encourages more blooms. Don't forget to harvest the seed pods, too! They're ready when they're plump and green, and can be pickled for a caper-like treat.

As our first frost approaches in early October, harvest any remaining flowers and seed pods to make the most of your plants. While the plants themselves will likely succumb to the cold, you can enjoy the fruits (and flowers!) of your labor well into the fall.

Here are the top 3 problems you might encounter with nasturtiums in the Northeast:

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and undersides of leaves. Leaves may be sticky or distorted.
• What causes it: Aphids are attracted to lush growth, which can be exacerbated by over-fertilizing. Our moderate summers and even rainfall provide favorable conditions for them.
• How to fix/prevent it: Nasturtiums are often used as a trap crop to draw aphids away from other plants. Check plants frequently and wash off aphids with a strong stream of water. Encourage beneficial insects like ladybugs.

Cabbage Caterpillars

• What it looks like: Holes in leaves, often with green droppings nearby. You might spot the caterpillars themselves, which are usually green and blend in well with the foliage.
• What causes it: Cabbage white butterflies lay their eggs on nasturtiums and other plants in the brassica family. Our cool nights and moderate summers are ideal for these pests.
• How to fix/prevent it: Handpick caterpillars off the plants. Cover plants with netting to prevent butterflies from laying eggs. Bacillus thuringiensis (Bt) is an effective organic control.

Black Fly

• What it looks like: Similar to aphids, these tiny black flies congregate on new growth and suck plant sap. Leaves may become distorted or yellowed.
• What causes it: Black flies thrive in moist conditions and are often found near water sources. Our moderate-to-humid climate can contribute to infestations.
• How to fix/prevent it: Improve air circulation around plants. Introduce beneficial insects like hoverflies. Insecticidal soap can be used as a last resort.

Northeast Specific Challenges: Our moderate heat, moderate-to-humid humidity, and even rainfall can create ideal conditions for some pests and diseases. However, nasturtiums are generally resilient and can thrive with proper care and monitoring. The key is to catch problems early and take action to prevent them from spreading.

Nasturtiums are excellent companion plants in the Northeast garden. They attract beneficial insects and can even deter some pests.

Plant them near tomatoes, cucumbers, and squash to help protect these crops from aphids and other pests. Nasturtiums act as a trap crop, drawing the pests away from your more valuable plants. They also do well with broccoli and cabbage, helping to deter cabbage moths. Avoid planting them near fennel, as it can inhibit their growth.