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When to plant Geraniums in Middlesex County County,

Middlesex County County sits in cold Zone 6b. Plant Geraniums May 1–May 15 for the single annual harvest; the October 17 first frost closes the window.

When to Plant Geraniums in Middlesex County, MA

Middlesex County, Massachusetts Zone 6b June

Top priorities for Middlesex County, Massachusetts gardeners in June

Each item below is timed to Middlesex County, Massachusetts's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 24
Avg. first frost October 17
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 15.1 hrs
A few tasks this June that'll pay off in July
  • Starting indoors: geraniums
  • First harvests: geraniums

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Geraniums (Pelargonium × hortorum) are tender perennials grown as warm-season annuals throughout North America. Prized for their bold flower clusters, long bloom period, and tolerance of summer heat when planted in well-drained soil, they anchor window boxes, containers, and bed borders from late spring until hard frost. Zones 9b–11b can overwinter plants in the ground.

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 Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Middlesex County, MA (Zone 6b) Moderate season
176 days
Last Spring Frost April 24
176 growing days
First Fall Frost October 17
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Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.7

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 9 Transplant: Apr 27 🌸 Bloom: Jul 6 – Oct 12
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Feb 13 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 16
Safe Start (90%) ✗ May not fit
Start indoors: Mar 4 Transplant: May 20 🌸 Bloom: Jul 29 – Nov 4

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 Geraniums's growing requirements.

Soil pH

Your soil pH (5.2–6.7) is more acidic than Geraniums prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Middlesex County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Geraniums.

How to Plant Geraniums

0.1"
Planting Depth
12"
Between Plants
14"
Between Rows

Succession Planting Geraniums

2
successive plantings in your 176-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Geraniums

Geraniums needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Geraniums 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.

Geraniums 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.

Geraniums needs ~1,488 GDD — county provides 3,080 GDD Excellent fit

Geraniums Planting Timeline — Middlesex County, MA

Geraniums 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

Plant 0.1" deep · 12" apart · Rows 14" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April
May Transplant Outdoors
June
July Bloom
August Bloom
September Bloom
October Bloom
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

176 days in Middlesex County

Growing Tips for Geraniums in Middlesex County

Direct sow Geraniums 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 — germination is slow and erratic without bottom heat (70–75°F). Transplant after frost danger passes. Geraniums rarely direct-sown; cuttings or transplants are the standard. Deadhead spent umbels weekly to maintain continuous bloom. Let soil dry slightly between waterings to prevent root rot. In zones 10–11 plants may be left in ground year-round or overwintered as houseplants.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Geraniums in Middlesex County, MA?

Middlesex County is in Zone 6b with an average last frost of April 24. Plan your Geraniums 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 Geraniums in Middlesex County County, ?

In Middlesex County County, , plant Geraniums 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 County, for Geraniums?

Middlesex County County sits in USDA Zone 6b. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.

Can Geraniums grow in Middlesex County County's climate?

Yes — Geraniums grows well in Middlesex County County's temperate climate. Middlesex County 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Middlesex County, MA. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.