Massachusetts gardeners should wait until after the last frost date to sow nasturtium seeds directly in the ground. The Best Time To Plant Nasturtium In Massachusetts typically falls between mid-May and early June, depending on your specific region within the state. This timing ensures your seeds germinate in warm soil and avoid damage from unexpected cold snaps.
Nasturtiums are one of the easiest flowers to grow from seed. They thrive in poor soil and need very little care once established. Getting the planting window right is the key to a long, colorful bloom season.
Understanding Massachusetts Frost Dates
Massachusetts spans USDA hardiness zones 5a through 7b. This means your last frost date varies by location. Coastal areas like Boston and Cape Cod warm up earlier than inland regions like the Berkshires.
Here are the average last frost dates for key Massachusetts regions:
- Eastern Massachusetts (Boston, Cambridge, Quincy): April 20 to May 5
- Central Massachusetts (Worcester, Springfield): May 1 to May 15
- Western Massachusetts (Pittsfield, Amherst): May 10 to May 25
- Cape Cod and Islands: April 15 to April 30
Nasturtium seeds will rot in cold, wet soil. Wait until the soil temperature reaches at least 55°F (13°C) before planting. A soil thermometer is a cheap tool that saves you from guessing.
Best Time To Plant Nasturtium In Massachusetts
Now lets break down the ideal planting window more precisly. The Best Time To Plant Nasturtium In Massachusetts is about two weeks after your local last frost date. This gives the soil time to warm up fully.
For most of Massachusetts, this means:
- Coastal areas: First week of May
- Central regions: Mid to late May
- Western areas: Late May to early June
If you want to start seeds indoors, do so 4 to 6 weeks before your last frost date. Use biodegradable pots because nasturtium roots are fragile and dislike transplanting. Plant the entire pot into the ground to avoid root disturbance.
Direct sowing is the simplest method. Nasturtiums germinate quickly in warm soil, usually within 7 to 14 days. You’ll see seedlings emerge fast once conditions are right.
Checking Soil Temperature Before Planting
Dont rely solely on the calendar. Check your soil temperature with a thermometer. Insert it 2 inches deep into the soil. If it reads below 55°F, wait another week.
Cold soil causes seeds to rot or germinate slowly. Warm soil gives you vigorous plants that resist pests better. Nasturtiums actually prefer slightly poor, well-draining soil. Rich soil leads to more leaves and fewer flowers.
What If You Plant Too Early?
Planting too early is the most common mistake. If a late frost hits your seedlings, they will die. You can cover them with row covers or cloth if a frost warning appears, but its easier to just wait.
If you plant seeds and a cold spell arrives, the seeds may rot underground. You wont see any sprouts and will need to replant. This wastes time and seeds.
Choosing The Right Nasturtium Varieties For Massachusetts
Not all nasturtiums are the same. Some varieties handle cooler springs better than others. For Massachusetts gardens, choose compact or trailing types that bloom quickly.
Top varieties for our climate:
- Jewel Mix: Dwarf plants, early blooming, great for borders
- Alaska Mix: Variegated leaves, flowers in multiple colors
- Empress of India: Deep red flowers, compact growth
- Spitfire: Trailing variety, ideal for hanging baskets
- Moonlight: Pale yellow flowers, vigorous climber
All these varieties mature in 55 to 65 days from seed. They bloom from late June until the first fall frost. In Massachusetts, that means you get 3 to 4 months of continuous color.
Where To Plant Nasturtiums In Your Garden
Nasturtiums need full sun for best blooming. In Massachusetts, full sun means at least 6 hours of direct sunlight daily. They can tolerate partial shade, but youll get fewer flowers.
Good planting locations include:
- Along garden borders
- In raised beds
- Hanging baskets or window boxes
- Around vegetable gardens as companion plants
- In containers on patios or decks
Nasturtiums repel aphids and whiteflies, making them excellent companions for tomatoes, cucumbers, and squash. They also attract pollinators like bees and butterflies.
Step-By-Step Guide To Planting Nasturtium Seeds
Follow these steps for successful planting in Massachusetts:
- Wait until after your last frost date and soil is above 55°F.
- Choose a sunny spot with well-draining soil. Avoid rich, fertilized areas.
- Soak seeds overnight in warm water. This softens the seed coat and speeds germination.
- Plant seeds 1/2 inch deep and 10 to 12 inches apart.
- Water gently after planting. Keep soil moist but not waterlogged.
- Mark the planting area so you dont forget where seeds are.
- Expect seedlings in 7 to 14 days. Thin to the strongest plants if needed.
For containers, use a pot at least 8 inches deep with drainage holes. Fill with regular potting soil, not heavy garden soil. Plant 2 to 3 seeds per pot, then thin to the best one.
Watering And Care After Planting
Nasturtiums are drought-tolerant once established. Water deeply once a week if there is no rain. Overwatering causes yellow leaves and fewer flowers.
Dont fertilize nasturtiums. They bloom best in poor soil. Too much nitrogen creates lush leaves but almost no flowers. If your soil is very poor, add a light layer of compost at planting time.
Deadheading spent flowers encourages more blooms. Simply pinch off faded flowers at the stem. You can also leave some to form seed pods for next year.
Common Problems When Planting Nasturtiums In Massachusetts
Even with perfect timing, issues can arise. Here are common problems and solutions:
- Aphids: Nasturtiums attract aphids away from other plants. Spray them off with water or use insecticidal soap.
- Yellow leaves: Usually from overwatering or too much fertilizer. Let soil dry out and stop feeding.
- No flowers: Too much shade or rich soil. Move plants to sunnier spot or reduce soil fertility.
- Seedlings dying: Likely from cold soil or frost. Wait longer before replanting.
- Slugs and snails: Hand pick them at night or use diatomaceous earth around plants.
Nasturtiums are generally pest-resistant. The biggest threat in Massachusetts is cold, wet spring weather. Once summer arrives, they grow with minimal effort.
Extending The Bloom Season
You can enjoy nasturtiums from June through October in Massachusetts. To extend the season:
- Plant a second batch of seeds in late June for fall blooms
- Bring container plants indoors before the first fall frost
- Cover plants with row covers during early fall cold snaps
- Harvest seeds for next year and let some self-sow
Nasturtiums are annuals in Massachusetts. They die with the first hard frost. But they often self-seed if you leave some flowers to go to seed. You might find volunteer plants next spring.
Using Nasturtiums In Your Massachusetts Landscape
Nasturtiums are versatile plants. Use them as ground cover, in hanging baskets, or climbing up trellises. Their round leaves and bright flowers add instant charm.
Edible flowers are a bonus. Nasturtium blooms have a peppery taste similar to watercress. Add them to salads, sandwiches, or as garnish. The leaves are also edible but spicier.
Companion planting benefits your vegetable garden. Plant nasturtiums near:
- Tomatoes: Repels whiteflies and aphids
- Cucumbers: Deters cucumber beetles
- Squash: Attracts pollinators and traps squash bugs
- Broccoli: Repels cabbage worms
This natural pest control reduces your need for chemicals. Nasturtiums are a win-win for beauty and function.
Harvesting Nasturtium Seeds
Save seeds from your best plants for next year. Let flowers fade and form green seed pods. When pods turn brown and dry, pick them. Store in a paper envelope in a cool, dry place.
Nasturtium seeds remain viable for 3 to 5 years. You can share them with friends or plant them in different areas of your garden. This saves money and preserves your favorite varieties.
Frequently Asked Questions
Q: Can I plant nasturtium seeds in Massachusetts in April?
A: Only if you live on Cape Cod or the islands and use row covers. For most of Massachusetts, wait until May. April soil is too cold and wet for nasturtium seeds.
Q: What is the latest time to plant nasturtium in Massachusetts?
A: You can plant as late as early July and still get blooms before frost. Later plantings produce fewer flowers but still add color to late summer gardens.
Q: Should I start nasturtium seeds indoors in Massachusetts?
A: Starting indoors is optional. It gives you a head start but requires careful transplanting. Direct sowing is easier and works well if you wait for warm soil.
Q: How deep should I plant nasturtium seeds in Massachusetts soil?
A: Plant seeds 1/2 inch deep. Any deeper and they may struggle to emerge. Shallow planting in loose soil works best.
Q: Do nasturtiums come back every year in Massachusetts?
A: No, they are annuals and die with frost. But they often self-seed if you let some flowers go to seed. You may get new plants next spring without replanting.
Final Tips For Massachusetts Gardeners
Timing is everything with nasturtiums. Wait for warm soil and stable weather. Dont rush the season. A late May planting often outperforms an early May one.
Nasturtiums thrive on neglect. Poor soil, minimal water, and full sun give you the best blooms. They are perfect for beginner gardeners or anyone who wants low-maintenance color.
In Massachusetts, you have a narrow but reliable window for planting. Mark your calendar for two weeks after your local last frost. Check soil temperature. Then sow your seeds and watch them grow.
With proper timing, your nasturtiums will bloom from late June through October. They will attract pollinators, repel pests, and brighten your garden. Plus, you can eat the flowers. What more could you ask from one plant?
So grab your seeds, wait for that warm May day, and get planting. Your Massachusetts garden will thank you.