When to plant Begonias in Middlesex County, MA
Middlesex County sits in cold Zone 6b. Plant Begonias May 1–May 15 for the single annual harvest; the October 17 first frost closes the window.
When to Plant Begonias in Middlesex County, MA
Your June gardening checklist
Your garden in Middlesex County, Massachusetts is working on a schedule, even when you're not. Here's where you should be this June.
July will be here before you know it — start on
- Starting indoors: begonias
- First harvests: begonias
Wax begonias (Begonia × semperflorens) are the workhorse shade bedding plant of American horticulture, offering continuous bloom from transplant to hard frost. Bronze or green-leaved varieties perform well from deep shade to full sun (in northern zones) and tolerate summer humidity better than most cool- season flowers. A staple of mass plantings, containers, and window boxes.
Middlesex County, Massachusetts is in USDA Zone 6b. 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 117 feet, Middlesex County receives approximately 43.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Begonias during the growing season.
Middlesex County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.7
Drainage
Well Drained
Begonias 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 Middlesex County
How your county's soil matches Begonias's growing requirements.
Soil pH
Your soil pH (5.2–6.7) overlaps with Begonias's range (5.5–6.5), though not a perfect match.
Soil Texture
The silt loam soil in Middlesex County is excellent for Begonias — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Begonias.
How to Plant Begonias
Succession Planting Begonias
Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.
Begonias Water Budget
Monthly Watering Guide for Begonias
Begonias needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Begonias Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.5" | 0" | ❄️ Dormant |
| Feb | — | 3.2" | 0" | ❄️ Dormant |
| Mar | — | 4.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jun | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jul | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.3" | 1" | 💧 Light watering |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | — | 3.3" | 0" | ❄️ Dormant |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Middlesex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Begonias 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.
Begonias Planting Timeline — Middlesex County, MA
Begonias Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 13 | Feb 13 – Feb 27 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Bloom | July 10 | Jul 10 – Oct 16 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 6b
📆 Growing Season
176 days in Middlesex County
Growing Tips for Begonias in Middlesex County
Direct sow Begonias outdoors after April 24 in Middlesex 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; surface-sow on moist mix under lights, do not cover. Bottom heat (70–75°F) speeds germination. Transplant after frost; begonias are not direct-sown in practice. Pinch seedlings once for branching. Keep soil evenly moist; avoid waterlogged conditions. Bronze-leaf types tolerate more sun; green- leaf types prefer shade to part-sun.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Begonias in Other Locations
Frequently Asked Questions
When should I plant Begonias in Middlesex County, MA?
Middlesex County is in Zone 6b with an average last frost of April 24. Plan your Begonias planting based on this frost date — see the calendar above for exact timing.
What planting zone is Middlesex County, MA?
Middlesex County, Massachusetts is in USDA Hardiness Zone 6b. The average last spring frost is April 24 and first fall frost is October 17.
When should I plant Begonias in Middlesex County, MA?
In Middlesex County, MA, plant Begonias 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 Middlesex County, MA for Begonias?
Middlesex County sits in USDA Zone 6b. Begonias grows reliably in zones 2a through 11b, so it's a good fit here.
Can Begonias grow in Middlesex County's climate?
Yes — Begonias grows well in Middlesex County's temperate climate. Middlesex County averages a 176-day frost-free season, with last frost around April 24 and first frost around October 17.
Your Middlesex County Garden Planner — Free
A 22-page printable planner built for Middlesex County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.