When to Plant Microgreens in Allegheny County, PA
Allegheny County, Pennsylvania gardeners: here's your May plan
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Indoor seed-starting week for microgreens
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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It's harvest week for microgreens
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.
Allegheny County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 25 and the first fall frost is October 28, giving you a growing season of approximately 186 days.
At an elevation of 118 feet, Allegheny County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Microgreens during the growing season.
Allegheny County Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.5
Drainage
Well Drained
Plant 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 Allegheny County
How your county's soil matches Microgreens's growing requirements.
Soil pH
Your soil pH (5.0–6.5) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Allegheny County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Microgreens.
How to Plant Microgreens
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Microgreens
Sow every 0.7 weeks. Last sowing by Oct 07 to harvest before frost.
For a dedicated fall crop, sow by Aug 19.
Plant Water Budget
Monthly Watering Guide for Microgreens
Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Microgreens Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3" | 0" | ❄️ Dormant |
| Feb | — | 3.1" | 0" | ❄️ Dormant |
| Mar | — | 3.7" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| May | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jun | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jul | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 3" | 1.3" | 💧 Light watering |
| Oct | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Allegheny County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Microgreens 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.
Microgreens Planting Timeline — Allegheny County, PA
Microgreens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 11 | Apr 11 – May 2 |
| Harvest | May 2 | May 2 – May 30 |
| Fall Sowing | August 19 | Aug 19 – Sep 2 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
7–21 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
186 days in Allegheny County
Growing Tips for Microgreens in Allegheny County
Direct sow Microgreens outdoors after April 25 in Allegheny County when soil has warmed and frost danger has passed.
Your generous 186.0-day season in Allegheny County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.
General growing tips
Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.
Microgreens in Other Locations
Frequently Asked Questions
When should I plant Microgreens in Allegheny County, PA?
Allegheny County is in Zone 6b with an average last frost of April 25. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Allegheny County, PA?
Allegheny County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 25 and first fall frost is October 28.
Your Allegheny County Garden Planner — Free
A 24-page printable planner built for Allegheny 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.