When to Plant Lobelia in USDA Zone 6a
Top priorities for Zone 6a gardeners in June
Welcome to June in Zone 6a. These are the moves that will have the biggest impact on your growing season.
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Begin indoor sowing: lobelia
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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Pick lobelia
If you can't use it all right away, check the food-preservation section of your planner.
Looking ahead to July
- First harvests: lobelia
Lobelia (Lobelia erinus) is a cool-season annual prized for the intense cobalt blue that is rare among bedding flowers. It blooms most prolifically in spring and early summer but stalls or dies back during heat peaks above 90°F. In zones 3–7 it delivers a long display; in zones 8–9 it is best treated as a spring annual that fades by midsummer. Trailing types cascade beautifully from containers and window boxes.
In Zone 6a, the average last spring frost is around April 10 and the first fall frost is around October 20, giving you a growing season of approximately 193 days.
Lobelia Planting Timeline — Zone 6a
Where Is USDA Zone 6a?
The map below highlights the states that contain Zone 6a. Click any state to see the Lobelia planting schedule for that location.
Lobelia Planting Calendar — Zone 6a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 6 | Feb 6 – Feb 20 |
| Transplant Outdoors | March 27 | Mar 27 – Apr 10 |
| Bloom | May 22 | May 22 – Aug 14 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Transplant Outdoors |
| April | Transplant Outdoors |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 6a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 6a with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
Days to Maturity
70–80 days
Soil pH
6 – 7
Zone Temperature Range
-10°F to -5°F average annual minimum
Growing Season
193 days (Zone 6a average)
Planting Specifications
| Plant Spacing | 6 inches apart |
| Row Spacing | 8 inches between rows |
Succession Planting Lobelia in Zone 6a
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Lobelia in Zone 6a
Start seeds indoors 10–12 weeks before last frost — seed is dust-fine and requires light to germinate; surface-sow and press gently. Keep at 65–70°F. Not reliably direct-sown. Transplant in cool weather, 2–4 weeks before last frost date is acceptable in zones 5+. Shear plants by one-third after the first bloom flush to encourage a second flush in fall. Provide afternoon shade in zones 7+ to extend bloom into summer.
Companion Planting
Good Companions
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
- Bonus: square-foot gardening guide + printable seasonal planners
Saving Lobelia Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Lobelia in Other Zones
Lobelia 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 Lobelia in Zone 6a?
In Zone 6a, plan your Lobelia planting around the average last frost date of April 10. Start seeds indoors around February 6. Transplant seedlings around March 27.
Can Lobelia grow in Zone 6a?
Yes, Lobelia can grow well in Zone 6a, hardy in USDA zones 3a through 9b. Zone 6a has a growing season of approximately 193 days, which is sufficient for Lobelia (70-80 days to maturity).
When can I harvest Lobelia in Zone 6a?
In Zone 6a, expect to harvest Lobelia from May 22 – August 14. Lobelia takes 70-80 days from planting to harvest.
What is the last frost date for Zone 6a?
The average last spring frost in Zone 6a is around April 10, and the first fall frost is around October 20. This gives a growing season of approximately 193 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Lobelia?
Good companion plants for Lobelia include Petunias, Sweet Alyssum, Begonias, Impatiens. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 6a Garden Planner — Free
A 22-page printable planner tailored to Zone 6a. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.