Nasturtium in Zone 6A — Northeast

Nasturtiums are a fantastic addition to any Zone 6A garden. Their peppery flavor brightens up salads, the vibrant flowers are edible and beautiful, and they are easy to grow. Plus, they attract beneficial insects, making them a valuable companion plant in your veggie patch. With the cool nights we often get here in the Northeast, the flavor can really develop.

While our short growing season and occasional late frosts can be a challenge, nasturtiums are quick to mature, making them a perfect fit. With a little planning, you can easily enjoy a bountiful harvest within our 178-day growing season.

Starting nasturtiums indoors is possible, but honestly, they prefer being direct-sown. They don't love having their roots disturbed. If you're itching to get a head start, sow seeds indoors late March through mid April, about four weeks before the last expected frost.

Use seed trays with good drainage and a light, well-draining potting mix. Keep the soil consistently moist by bottom watering to avoid damping off, and provide plenty of light. A sunny windowsill or grow lights will do the trick.

Remember, our springs can be a bit unpredictable. So, even if you start indoors, be prepared to protect your seedlings if a late frost threatens after transplanting. Direct sowing is more reliable.

If you started your nasturtiums indoors, it's time to transplant them outdoors late April through late May, after 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, and space the plants 10-12 inches apart. Keep an eye on the weather forecast; a sudden cold snap can still happen, so be ready to cover your seedlings if necessary.

Direct sowing is the easiest and most reliable method for growing nasturtiums in the Northeast. Wait until late April through early August, once the soil has warmed up a bit and the risk of frost is gone.

Prepare the soil by loosening it and removing any large rocks – you know how our New England soil can be. Sow the seeds directly into the ground, about half an inch deep, spacing them 10-12 inches apart. Keep the soil consistently moist until the seedlings emerge.

Nasturtiums are wonderfully low-maintenance when it comes to watering. They actually thrive in slightly poor, dry soil, so resist the urge to overwater. Too much water or fertilizer will result in lush foliage but fewer flowers.

During the peak of summer, when temperatures are consistently in the 80s and humidity is moderate-to-humid, 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, either from rainfall or irrigation. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid climate.

In spring and fall, when temperatures are cooler and rainfall is more frequent, you'll likely need to water less often. Overwatering can lead to root rot. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. A light layer of mulch can help retain moisture in the soil and suppress weeds, but don't overdo it, as nasturtiums prefer drier conditions.

You can expect your first harvest of nasturtium flowers and leaves around late June through mid October, about 55 days after sowing. The flowers are ready to pick when they are fully open and their color is vibrant. The leaves can be harvested at any time.

To harvest, simply snip off the flowers or leaves with scissors or your fingers. Avoid pulling or tugging, which can damage the plant. Regular harvesting will encourage the plant to produce more flowers and leaves throughout the season.

As the first frost approaches in mid- October, you can harvest any remaining flowers and leaves. The seed pods can also be harvested and pickled for a caper-like treat.

Here are a few common problems you might encounter with nasturtiums in your Northeast garden:

Aphids:

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaves, often causing distorted growth.
• What causes it: Aphids are attracted to stressed plants and can multiply quickly in warm weather.
• How to fix/prevent it: Nasturtiums are often used as a trap crop for aphids, drawing them away from other plants. If the infestation is heavy, spray with insecticidal soap or neem oil.

Cabbage Caterpillars:

• What it looks like: Holes in leaves, and green caterpillars munching on the foliage.
• What causes it: Cabbage white butterflies lay their eggs on nasturtiums, and the caterpillars hatch and feed on the leaves.
• How to fix/prevent it: Handpick caterpillars off the plants. Cover plants with row covers to prevent butterflies from laying eggs.

Black Fly:

• What it looks like: Tiny black flies swarming around the plants, especially in the soil.
• What causes it: Overwatering and poor drainage create ideal conditions for black fly larvae to thrive in the soil.
• How to fix/prevent it: Allow the soil to dry out between waterings. Improve drainage by adding compost or perlite to the soil. Use sticky traps to catch adult flies.

Northeast Specific Challenges: Our moderate heat, moderate-to-humid humidity, and even rainfall can create favorable conditions for pests and diseases. Regular monitoring and prompt action are key to keeping your nasturtiums healthy and productive.

Nasturtiums are excellent companion plants in the Northeast garden. They attract beneficial insects and can help deter pests from other crops.

Good companions include tomatoes, cucumbers, and squash. Nasturtiums deter pests like squash bugs and aphids, which can damage these crops. They also do well planted near broccoli and cabbage, luring cabbage white butterflies away from your precious brassicas.

There aren't really any bad companions for nasturtiums, making them a versatile addition to any garden bed.