When to plant Lobelia in Worcester County, MA
Worcester County's 176-day season only supports one Lobelia planting per year. Sow between April 10 and April 24 for the best chance at full maturity before October 17.
When to Plant Lobelia in Worcester County, MA
June in the garden — Worcester County, Massachusetts
June is a pivotal month for Worcester County, Massachusetts gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Start lobelia indoors
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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Basket week: lobelia
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
To set up a strong July, finish these tasks
- 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.
Worcester County, Massachusetts is in USDA Zone 6a. The average last spring frost is April 24 and the first fall frost is October 17, giving you a growing season of approximately 176 days.
At an elevation of 972 feet, Worcester County receives approximately 38 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Lobelia during the growing season.
Worcester County Soil Profile
Soil Type
Silt Loam
Soil pH
4.8-6.3
Drainage
Well Drained
Lobelia Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Worcester County
How your county's soil matches Lobelia's growing requirements.
Soil pH
Your soil pH (4.8–6.3) is more acidic than Lobelia prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Worcester County is excellent for Lobelia — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Lobelia.
Organic Matter
Organic matter is moderate (3.7%). Annual compost additions will help Lobelia.
How to Plant Lobelia
Succession Planting Lobelia
Sow every 8 weeks. Last sowing by Jul 29 to harvest before frost.
Lobelia Water Budget
Monthly Watering Guide for Lobelia
Lobelia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Lobelia Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.3" | 0" | ❄️ Dormant |
| Feb | — | 2.6" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 3" | 1.3" | 💧 Light watering |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 3.3" | 1" | 💧 Light watering |
| Sep | 4.3" | 3" | 1.3" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 3.3" | 0" | ❄️ Dormant |
| Dec | — | 2.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Worcester County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lobelia Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Lobelia Planting Timeline — Worcester County, MA
Lobelia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | April 10 | Apr 10 – Apr 24 |
| Bloom | June 5 | Jun 5 – Aug 28 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors |
| May | — |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
70–80 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6a
📆 Growing Season
176 days in Worcester County
Growing Tips for Lobelia in Worcester County
Direct sow Lobelia outdoors after April 24 in Worcester County when soil has warmed and frost danger has passed.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Lobelia in Other Locations
Frequently Asked Questions
When should I plant Lobelia in Worcester County, MA?
Worcester County is in Zone 6a with an average last frost of April 24. Plan your Lobelia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Worcester County, MA?
Worcester County, Massachusetts is in USDA Hardiness Zone 6a. The average last spring frost is April 24 and first fall frost is October 17.
When should I plant Lobelia in Worcester County, MA?
In Worcester County, MA, plant Lobelia after the last frost (around April 24) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Worcester County, MA for Lobelia?
Worcester County sits in USDA Zone 6a. Lobelia grows reliably in zones 3a through 9b, so it's a good fit here.
Can Lobelia grow in Worcester County's climate?
Yes — Lobelia grows well in Worcester County's temperate climate. Worcester County averages a 176-day frost-free season, with last frost around April 24 and first frost around October 17.
Your Worcester County Garden Planner — Free
A 22-page printable planner built for Worcester County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.