When to Plant Microgreens in Philadelphia County, PA
What to do in May
Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.
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Sow microgreens in trays indoors
Starting these indoors now means sturdy transplants ready the moment your soil warms up.
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Harvest microgreens as they ripen
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
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.
Philadelphia County, Pennsylvania is in USDA Zone 7b. The average last spring frost is April 16 and the first fall frost is October 24, giving you a growing season of approximately 191 days.
At an elevation of 996 feet, Philadelphia County receives approximately 48.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Microgreens during the growing season.
Philadelphia County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.7
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 Philadelphia County
How your county's soil matches Microgreens's growing requirements.
Soil pH
Your soil pH (5.2–6.7) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Philadelphia County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (4.0%). 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 03 to harvest before frost.
For a dedicated fall crop, sow by Aug 15.
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 | — | 3.9" | 0" | ❄️ Dormant |
| Feb | — | 3.7" | 0" | ❄️ Dormant |
| Mar | — | 3.8" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Jul | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.3" | 0" | ❄️ Dormant |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Philadelphia 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 — Philadelphia County, PA
Microgreens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Direct Sow | April 2 | Apr 2 – Apr 23 |
| Harvest | April 23 | Apr 23 – May 21 |
| Fall Sowing | August 15 | Aug 15 – Aug 29 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
7–21 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 7b
📆 Growing Season
191 days in Philadelphia County
Growing Tips for Microgreens in Philadelphia County
Direct sow Microgreens outdoors after April 16 in Philadelphia County when soil has warmed and frost danger has passed.
Your generous 191.0-day season in Philadelphia 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 Philadelphia County, PA?
Philadelphia County is in Zone 7b with an average last frost of April 16. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Philadelphia County, PA?
Philadelphia County, Pennsylvania is in USDA Hardiness Zone 7b. The average last spring frost is April 16 and first fall frost is October 24.
Your Philadelphia County Garden Planner — Free
A 24-page printable planner built for Philadelphia County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.