Nasturtium in Zone 5A — Great Plains

Nasturtiums are a fantastic addition to any Great Plains garden. Their peppery leaves and bright flowers add zest to salads and make beautiful garnishes. Plus, they attract beneficial insects, and they're surprisingly drought-tolerant, which is a real asset in our variable climate.

Our extreme weather can be a challenge, but Nasturtiums are quick growers. With a growing season around 168 days, you'll have plenty of time to enjoy their beauty and flavor. Careful timing is key, and we'll walk you through it.

Starting Nasturtiums indoors isn't essential, but it can give you a head start, especially if you're further north and have a shorter growing season. If you want to go this route, start your seeds indoors from late March through mid April, about four weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep them warm and provide plenty of light – a sunny windowsill or grow lights work well. Bottom watering is ideal to prevent damping off, which can be a problem in our variable spring weather.

Transplant your Nasturtium seedlings outdoors from early to late May, after the danger of frost has passed. Be sure to harden them off for about a week beforehand. Gradually expose them to outdoor conditions to prevent shock.

Space them 10-12 inches apart in a sunny spot with well-drained soil. Keep an eye on the forecast; even in late May, we can get unexpected temperature swings that could stress young plants.

Direct sowing is the preferred method for Nasturtiums, as they don't always love being transplanted. Wait until early May, after the last frost, to direct sow your seeds. You have about a 3-month window, so you can even sow until early August!

Prepare the soil by loosening it and removing any large clumps. Nasturtiums aren't picky – they actually prefer soil that's not too rich. Sow seeds about ½ inch deep and space them 10-12 inches apart. Keep the soil consistently moist until the seedlings emerge.

Nasturtiums are surprisingly drought-tolerant, which makes them perfect for our Great Plains climate. Overwatering is a far bigger problem than underwatering with these plants.

During the spring, when rainfall is more frequent, you might not need to water them at all unless we're experiencing a dry spell. In the heat of summer, when temperatures can soar, check the soil moisture regularly. Stick your finger about two inches deep – 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 plants to avoid wetting the foliage, especially with our moderate humidity. Yellowing leaves can be a sign of overwatering, while wilting leaves indicate underwatering. Mulching around the plants can help retain moisture and regulate soil temperature, especially during our extreme temperature swings.

You can expect your first harvest of Nasturtium flowers and leaves from late June through early October, about 55 days after planting. The flowers are ready to harvest when they are fully open and brightly colored. The leaves can be harvested at any time.

To harvest, simply snip off the flowers or leaves with scissors or your fingers. Be gentle to avoid damaging the plant. Regular harvesting will encourage continued production. As the first frost approaches in early October, 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 the Great Plains:

Aphids *What it looks like:* Clusters of tiny green, black, or brown insects on the stems and undersides of leaves. Leaves may be distorted or sticky. *What causes it:* Aphids are attracted to stressed plants, and our variable weather can sometimes weaken them. *How to fix/prevent it:* Nasturtiums actually attract aphids, acting as a trap crop to keep them away from other plants. You can also blast them off with a strong stream of water from the hose.

Cabbage Caterpillars *What it looks like:* Holes in the leaves, often with green droppings nearby. You might spot the caterpillars themselves – usually green or white. *What causes it:* Cabbage white butterflies lay their eggs on the leaves, and the caterpillars hatch and start feeding. *How to fix/prevent it:* Handpick the caterpillars off the plants. Covering plants with row covers can prevent butterflies from laying eggs.

Black Fly *What it looks like:* Similar to aphids, black flies are small, dark insects that cluster on new growth. They suck sap from the plant. *What causes it:* Like aphids, they are attracted to stressed plants. *How to fix/prevent it:* A strong blast of water can dislodge them. Encourage beneficial insects like ladybugs, which prey on black flies.

Great Plains Specific Challenges: Our hot summers, coupled with variable rainfall, can stress Nasturtiums if they're not watered properly. Make sure to monitor the soil moisture and water deeply but infrequently. Wind protection is also essential, as strong winds can damage the delicate leaves and flowers.

Nasturtiums make great companions for many plants in the Great Plains garden. They are particularly beneficial for:

• Tomatoes: Nasturtiums can help repel tomato hornworms.
• Cucumbers & Squash: They deter squash bugs and cucumber beetles.
• Broccoli & Cabbage: They attract cabbage white butterflies away from your brassicas, acting as a trap crop.

Avoid planting Nasturtiums near fennel, as it can inhibit their growth. Also, be mindful of planting them near legumes, as Nasturtiums can sometimes attract bean beetles.