When to Plant Nasturtium in USDA Zone 4b
June in the garden — Zone 4b
A quick June briefing for Zone 4b gardeners — what's urgent, what's next, and what can wait.
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Sow nasturtium in trays indoors
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
Get ahead of July
- First harvests: nasturtium
Nasturtium (Tropaeolum majus) is a fast-growing annual with distinctive round, lily-pad leaves and bold trumpet-shaped blooms in warm oranges, reds, and yellows. Both the flowers and leaves are edible with a peppery watercress flavor. Planted near vegetables, nasturtiums act as a sacrifice trap-crop, luring aphids away from more valuable plants. They thrive in poor, dry soil — rich conditions produce lush foliage but few flowers.
In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.
Nasturtium Planting Timeline — Zone 4b
Where Is USDA Zone 4b?
The map below highlights the states that contain Zone 4b. Click any state to see the Nasturtium planting schedule for that location.
Nasturtium Planting Calendar — Zone 4b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 3 | Apr 3 – Apr 17 |
| Transplant Outdoors | May 8 | May 8 – May 22 |
| Direct Sow | May 8 | May 8 – May 29 |
| Bloom | July 3 | Jul 3 – Sep 25 |
Plant 0.5" deep · 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Free Zone 4b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
Days to Maturity
55–65 days
Soil pH
6 – 8
Zone Temperature Range
-25°F to -20°F average annual minimum
Growing Season
155 days (Zone 4b average)
Planting Specifications
| Planting Depth | 0.5 inches |
| Plant Spacing | 10 inches apart |
| Row Spacing | 12 inches between rows |
Succession Planting Nasturtium in Zone 4b
Sow every 6.3 weeks for continuous harvest throughout the season.
Growing Tips for Nasturtium in Zone 4b
Zone 4b has a short growing season (~155 days). Start Nasturtium indoors early and use season-extension techniques like row covers and cold frames.
Direct-sow large seeds 1/2 inch deep after last frost; soak seeds overnight to speed germination (7-10 days). Nasturtiums dislike root disturbance so direct sowing is strongly preferred. Avoid fertilizing — poor soil brings the best bloom. Trailing types can cover banks and climb trellises; dwarf types suit containers. In hot climates (zones 9+) plant in fall for winter/spring bloom as plants struggle in peak summer heat.
Companion Planting
Good Companions
Avoid Planting Near
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
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Saving Nasturtium Seeds
Recommended for Your Garden
Full-spectrum LED lights for starting seeds indoors when daylight is limited.
Warm soil for faster germination of heat-loving crops like tomatoes and peppers.
Protect plants from frost, wind, and pests while letting light and water through.
Related Plants
Nasturtium in Other Zones
Nasturtium by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Nasturtium in Zone 4b?
In Zone 4b, plan your Nasturtium planting around the average last frost date of May 1. Start seeds indoors around April 3. Direct sow outdoors around May 8. Transplant seedlings around May 8.
Can Nasturtium grow in Zone 4b?
Yes, Nasturtium can grow well in Zone 4b, hardy in USDA zones 2a through 11b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Nasturtium (55-65 days to maturity).
When can I harvest Nasturtium in Zone 4b?
In Zone 4b, expect to harvest Nasturtium from July 3 – September 25. Nasturtium takes 55-65 days from planting to harvest.
What is the last frost date for Zone 4b?
The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Nasturtium?
Good companion plants for Nasturtium include Tomatoes, Cucumbers, Squash, Radishes. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 4b Garden Planner — Free
A 22-page printable planner tailored to Zone 4b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.