When to plant Mustard Greens in New Castle County County,
Plant Mustard Greens in New Castle County County from March 23 to April 13 in spring. New Castle County County sits in USDA Zone 7b, with last frost around April 6 and first frost on October 31. A second sowing from August 22 to September 5 extends the harvest into fall.
When to Plant Mustard Greens in New Castle County, DE
June in New Castle County, Delaware — your action list
Your garden in New Castle County, Delaware is working on a schedule, even when you're not. Here's where you should be this June.
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Harvest mustard greens as they ripen
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
Get ahead of July
- First harvests: mustard greens
Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.
New Castle County, Delaware is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 31, giving you a growing season of approximately 208 days.
At an elevation of 415 feet, New Castle County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Mustard Greens during the growing season.
New Castle County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-7.1
Drainage
Well Drained
Mustard Greens 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 New Castle County
How your county's soil matches Mustard Greens's growing requirements.
Soil pH
Your soil pH (5.2–7.1) overlaps with Mustard Greens's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in New Castle County is excellent for Mustard Greens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Mustard Greens.
How to Plant Mustard Greens
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Mustard Greens
Sow every 3.4 weeks. Last sowing by Sep 11 to harvest before frost.
For a dedicated fall crop, sow by Aug 22.
Mustard Greens Water Budget
Monthly Watering Guide for Mustard Greens
Mustard Greens needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Mustard Greens Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.4" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 3.4" | 0" | ❄️ Dormant |
| Apr | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| May | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.3" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.1" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.4" | 0" | ❄️ Dormant |
| Dec | — | 2.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in New Castle County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mustard Greens 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.
Mustard Greens Planting Timeline — New Castle County, DE
Mustard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | April 6 | Apr 6 – Apr 20 |
| Direct Sow | March 23 | Mar 23 – Apr 13 |
| Harvest | May 11 | May 11 – Jul 13 |
| Fall Sowing | August 22 | Aug 22 – Sep 5 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
30–50 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
208 days in New Castle County
Growing Tips for Mustard Greens in New Castle County
Direct sow Mustard Greens outdoors after April 06 in New Castle County when soil has warmed and frost danger has passed.
Your generous 208.0-day season in New Castle County allows multiple plantings of Mustard Greens. Sow every 15.0 days for continuous harvest.
Common pests for Mustard Greens in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mustard Greens in Other Locations
Frequently Asked Questions
When should I plant Mustard Greens in New Castle County, DE?
New Castle County is in Zone 7b with an average last frost of April 6. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is New Castle County, DE?
New Castle County, Delaware is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 31.
When should I plant Mustard Greens in New Castle County County, ?
In New Castle County County, , plant Mustard Greens after the last frost (around April 6) and before the first frost (around October 31). Best results when soil holds above 50°F.
What growing zone is New Castle County County, for Mustard Greens?
New Castle County County sits in USDA Zone 7b. Mustard Greens grows reliably in zones 2a through 11b, so it's a good fit here.
Can Mustard Greens grow in New Castle County County's climate?
Yes — Mustard Greens grows well in New Castle County County's temperate climate. New Castle County County averages a 208-day frost-free season, with last frost around April 6 and first frost around October 31.
Your New Castle County Garden Planner — Free
A 22-page printable planner built for New Castle 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.