New Jersey’s coastal influence moderates temperatures, making mid-May the ideal time to plant nasturtium directly in the garden. Knowing the best time to plant nasturtium in New Jersey is key to getting those bright, edible flowers all summer long.
Nasturtiums are one of the easiest flowers to grow from seed. They don’t like cold soil or frost. Plant them too early, and they’ll sulk or rot. Plant them at the right time, and they’ll explode with color.
This guide covers everything you need to know about timing, soil prep, and care for nasturtiums in the Garden State.
Best Time To Plant Nasturtium In New Jersey
The short answer is mid-May, after the last frost date. But New Jersey is a long state, from the Highlands to the Shore. Your exact planting window shifts by a week or two depending on where you live.
Here is the breakdown by region:
- North Jersey (Sussex, Bergen, Passaic): Wait until May 20–May 30. Frost can linger into late May in higher elevations.
- Central Jersey (Middlesex, Mercer, Monmouth): Aim for May 10–May 20. Soil warms up faster here.
- South Jersey (Atlantic, Cape May, Cumberland): Plant as early as May 1–May 10. Coastal breezes keep nights mild.
Check your local frost dates online. Your county extension office has the most accurate info. Soil temperature should be at least 60°F (15°C) for good germination.
If you want a head start, you can start seeds indoors 4–6 weeks before your last frost. Use peat pots because nasturtiums hate root disturbance. Transplant carefully after hardening off for a week.
Why Timing Matters So Much
Nasturtiums are tender annuals. They cannot handle frost. A late cold snap will kill seedlings instantly. Even cool, wet soil can cause seeds to rot before they sprout.
On the flip side, planting too late in summer means less bloom time before fall. Nasturtiums love cool nights but not heat stress. In New Jersey’s humid July, they can get leggy and stop flowering if planted too late.
The sweet spot is when soil is warm but air temps are still moderate—usually late spring.
How To Prepare Your Garden For Nasturtiums
Good soil prep makes timing work better. Follow these steps before you plant.
Choose The Right Spot
Nasturtiums need full sun for best blooms. In South Jersey’s intense heat, some afternoon shade is fine. They tolerate poor soil, which is actually a plus. Rich soil makes them grow lots of leaves but few flowers.
- Pick a spot with well-draining soil. No standing water.
- They grow well in containers, hanging baskets, and window boxes.
- They also work as ground cover or trailing over walls.
Soil Preparation
Nasturtiums are not heavy feeders. Do not add compost or fertilizer. Too much nitrogen equals lush leaves and zero blooms.
Just loosen the soil to about 6 inches deep. Remove rocks and weeds. If your soil is heavy clay, mix in some sand or perlite to improve drainage.
For containers, use a standard potting mix. Do not add slow-release fertilizer.
Seed Treatment (Optional But Helpful)
Nasturtium seeds have a hard outer coat. Some gardeners soak them overnight in warm water before planting. This speeds up germination by 2–3 days.
You can also nick the seed coat with a nail file. Be careful not to damage the inside. This is called scarification.
If you skip this step, seeds will still germinate—just slower.
Step-By-Step Planting Guide
Here is how to plant nasturtiums at the Best Time To Plant Nasturtium In New Jersey.
- Wait for the right date: Use the regional guide above. Check the 10-day forecast for no frost.
- Soak seeds (optional): Soak in room-temperature water for 8–12 hours. Drain before planting.
- Plant seeds 1 inch deep: Push them into the soil with your finger. Cover loosely with soil.
- Space seeds 10–12 inches apart: Dwarf varieties can be closer, 8 inches apart. Trailing types need more room.
- Water gently: Use a spray nozzle so you don’t wash seeds away. Keep soil moist but not soggy.
- Watch for sprouts: In 7–14 days, you’ll see seedlings. Thin to the strongest one per spot if needed.
If you are transplanting seedlings from indoors, dig a hole the same size as the pot. Place the plant in, firm soil around it, and water well. Handle roots gently.
Direct Sowing Vs. Indoor Starts
Direct sowing is easiest. Nasturtiums dislike being moved. Their taproots are sensitive. But indoor starts give you a 3–4 week head start, which helps in North Jersey’s short season.
For direct sowing, plant after last frost. For indoor starts, plant seeds in peat pots 4 weeks before last frost. Harden off plants for 5–7 days before moving outside.
Hardening off means putting them outside for a few hours each day, increasing time gradually. This prevents transplant shock.
Caring For Nasturtiums After Planting
Once your nasturtiums are in the ground, care is minimal. That’s why they are great for beginners.
Watering
Water deeply once a week if there is no rain. In containers, water more often—every 2–3 days in hot weather. Let the soil dry out between waterings. Overwatering causes yellow leaves and root rot.
Check soil moisture by sticking your finger 1 inch deep. If dry, water. If moist, wait.
Fertilizing
Do not fertilize. Seriously. Nasturtiums bloom best in lean soil. If you must feed, use a very diluted liquid fertilizer with low nitrogen, like a bloom booster (high phosphorus). Once a month is plenty.
Too much fertilizer = big leaves, few flowers.
Deadheading
Remove spent flowers to encourage more blooms. Pinch off the flower stem at the base. This stops the plant from making seeds and redirects energy to new flowers.
You can also let some flowers go to seed. Nasturtium seeds are edible and taste like peppery capers. Pick them green and pickle them.
Pest Control
Nasturtiums are natural pest repellents. They attract aphids away from your vegetables. If aphids show up on your nasturtiums, just spray them off with a strong stream of water.
Other pests like caterpillars or slugs can be picked off by hand. Use diatomaceous earth around plants for slugs.
Do not use chemical pesticides on nasturtiums if you plan to eat the flowers or seeds.
Companion Planting With Nasturtiums
Nasturtiums are excellent companions in the vegetable garden. They deter squash bugs, whiteflies, and cucumber beetles. Plant them near:
- Tomatoes
- Cucumbers
- Squash
- Broccoli
- Cabbage
They also attract pollinators like bees and butterflies. The bright flowers bring beneficial insects to your garden.
Avoid planting nasturtiums near beans or peas. They can compete for nutrients and space.
Growing Nasturtiums In Containers
Container gardening is popular in New Jersey, especially for apartment dwellers. Nasturtiums thrive in pots.
Pot Size
Use a pot at least 8 inches wide for dwarf varieties. For trailing types, use a 12-inch pot or a hanging basket. Make sure the pot has drainage holes.
Soil
Use a standard potting mix. Do not add fertilizer. Add perlite for extra drainage if needed.
Watering
Containers dry out faster. Water when the top inch of soil feels dry. In summer heat, you may need to water daily. Check every morning.
Feeding
Even less fertilizer than in-ground plants. If leaves turn pale green, use a very weak liquid fertilizer once. Otherwise, leave them alone.
Harvesting Nasturtium Flowers And Leaves
Both flowers and leaves are edible. They have a peppery, radish-like taste. Harvest in the morning when flowers are fully open.
- Pick flowers by pinching the stem just behind the bloom.
- Leaves can be picked individually. Young leaves are milder.
- Use them fresh in salads, as garnishes, or on sandwiches.
- Stuff flowers with goat cheese for a fancy appetizer.
Wash gently before eating. Avoid flowers that have been sprayed with pesticides.
Common Problems And Solutions
Even easy plants have issues. Here are the most common nasturtium problems in New Jersey.
Yellow Leaves
Usually from overwatering or too much fertilizer. Let soil dry out. Stop feeding. If leaves are yellow with green veins, it might be a nutrient deficiency, but that’s rare.
No Flowers, Lots Of Leaves
Too much nitrogen. Did you fertilize? Stop. Also, check sunlight. Nasturtiums need at least 6 hours of direct sun. Too much shade = leaves only.
Leggy Growth
Not enough sun or too much water. Move to a sunnier spot. Cut back on watering. You can also pinch back stems to encourage bushier growth.
Aphids
Spray with water. If severe, use insecticidal soap. Nasturtiums are trap crops for aphids, so a few are normal.
Powdery Mildew
White powder on leaves. Usually from poor air circulation or high humidity. Space plants properly. Water at the base, not on leaves. Remove affected leaves.
Extending The Bloom Season
Nasturtiums bloom from late spring until the first fall frost. In New Jersey, that’s usually October. To keep them going:
- Deadhead regularly.
- Water consistently.
- Protect from extreme heat with afternoon shade.
- In early fall, you can cover plants on cold nights to extend bloom a few weeks.
If you want nasturtiums later in the season, you can do a second planting in late June. They will bloom in late summer and fall. This works well in South Jersey where summers are long.
Saving Seeds For Next Year
Nasturtiums produce large seeds that are easy to save. Let some flowers go to seed. The seeds will turn brown and fall off. Collect them before they drop.
Dry seeds on a paper towel for a week. Store in a paper envelope in a cool, dark place. They stay viable for 3–5 years.
Label the envelope with the year and variety. Next spring, you can plant them at the Best Time To Plant Nasturtium In New Jersey again.
Frequently Asked Questions
Can I plant nasturtiums in New Jersey in July?
Yes, but they will bloom later and for a shorter time. July planting works best for fall blooms. Water well during heat waves.
What is the latest time to plant nasturtium in New Jersey?
You can plant as late as early August for fall flowers. But you risk frost killing them before they bloom. Mid-July is safer.
Do nasturtiums come back every year in New Jersey?
No, they are annuals. They die with the first hard frost. But they often self-seed. If you let seeds drop, new plants may appear next spring.
How long do nasturtiums take to bloom from seed?
About 50–70 days from planting. Direct-sown seeds in mid-May will bloom by early July. Indoor starts bloom earlier, in June.
Can I grow nasturtiums in partial shade in New Jersey?
They will grow but produce fewer flowers. Full sun (6+ hours) is best. In South Jersey’s hot afternoons, some shade is okay.
Final Tips For Success
Timing is everything. Wait for warm soil. Do not rush. Nasturtiums are forgiving if you get the basics right.
Here is a quick checklist:
- Check your local frost date.
- Wait for soil temp above 60°F.
- Plant seeds 1 inch deep.
- Water sparingly.
- No fertilizer.
- Deadhead for more blooms.
- Enjoy the edible flowers.
Nasturtiums are a low-effort, high-reward plant. They add color to your garden and spice to your plate. With the right timing in New Jersey, you’ll have blooms from June through October.
So mark your calendar for mid-May. Prep your soil. Soak those seeds. And get ready for a summer full of vibrant, peppery flowers.