When to Plant Lemon Balm in Philadelphia County, PA
Philadelphia County, Pennsylvania gardeners: here's your May plan
Your garden in Philadelphia County, Pennsylvania is working on a schedule, even when you're not. Here's where you should be this May.
Looking ahead to June
- First harvests: lemon balm
Lemon balm is a vigorous perennial herb with bright green, lemon-scented leaves. It makes a refreshing tea and is easy to grow but can spread aggressively.
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 Lemon Balm 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 Lemon Balm's growing requirements.
Soil pH
Your soil pH (5.2–6.7) overlaps with Lemon Balm's range (5.5–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Philadelphia County is excellent for Lemon Balm — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Lemon Balm.
How to Plant Lemon Balm
Succession Planting Lemon Balm
Sow every 6.9 weeks. Last sowing by Aug 15 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Lemon Balm
Lemon Balm needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Lemon Balm Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.9" | 0" | ❄️ Dormant |
| Feb | — | 3.7" | 0" | ❄️ Dormant |
| Mar | — | 3.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 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.
Lemon Balm 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.
Lemon Balm Planting Timeline — Philadelphia County, PA
Lemon Balm Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Harvest | June 25 | Jun 25 – Aug 13 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–70 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
191 days in Philadelphia County
Growing Tips for Lemon Balm in Philadelphia County
Direct sow Lemon Balm outdoors after April 16 in Philadelphia County when soil has warmed and frost danger has passed.
General growing tips
Start from seed, cuttings, or divisions. Contain in pots or use barriers to prevent spreading. Harvest frequently to keep plants bushy and prevent flowering.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Lemon Balm in Other Locations
Frequently Asked Questions
When should I plant Lemon Balm in Philadelphia County, PA?
Philadelphia County is in Zone 7b with an average last frost of April 16. Plan your Lemon Balm 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.