When to Plant Radicchio in Sussex County, DE
May in the garden — Sussex County, Delaware
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Sussex County, Delaware.
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Sow radicchio in trays indoors
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
Before June arrives, get these ready
- First harvests: radicchio
Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.
Sussex County, Delaware is in USDA Zone 7b. The average last spring frost is April 3 and the first fall frost is November 7, giving you a growing season of approximately 218 days.
At an elevation of 1,090 feet, Sussex County receives approximately 46 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Radicchio during the growing season.
Sussex County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.5
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 Sussex County
How your county's soil matches Radicchio's growing requirements.
Soil pH
Your soil pH (5.6–6.5) overlaps with Radicchio's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Sussex County is excellent for Radicchio — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.8%). Annual compost additions will help Radicchio.
How to Plant Radicchio
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radicchio
Sow every 6.9 weeks. Last sowing by Aug 19 to harvest before frost.
For a dedicated fall crop, sow by Aug 29.
Plant Water Budget
Monthly Watering Guide for Radicchio
Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Radicchio Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.5" | 0" | ❄️ Dormant |
| Feb | — | 3.5" | 0" | ❄️ Dormant |
| Mar | — | 3.9" | 0" | ❄️ Dormant |
| Apr | 3" | 3.7" | 0" | ✅ Rainfall sufficient |
| May | 3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jun | 3" | 3.7" | 0" | ✅ Rainfall sufficient |
| Jul | 3" | 5.3" | 0" | ✅ Rainfall sufficient |
| Aug | 3" | 4.1" | 0" | ✅ Rainfall sufficient |
| Sep | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Oct | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | 3" | 3.2" | 0" | ✅ Rainfall sufficient |
| Dec | — | 3.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Sussex County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Radicchio 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.
Radicchio Planting Timeline — Sussex County, DE
Radicchio Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | April 3 | Apr 3 – Apr 17 |
| Direct Sow | March 20 | Mar 20 – Apr 10 |
| Harvest | June 5 | Jun 5 – Jul 10 |
| Fall Sowing | August 29 | Aug 29 – Sep 12 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.7"/week · Natural rainfall sufficient
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
218 days in Sussex County
Growing Tips for Radicchio in Sussex County
Direct sow Radicchio outdoors after April 03 in Sussex County when soil has warmed and frost danger has passed.
Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Radicchio in Other Locations
Frequently Asked Questions
When should I plant Radicchio in Sussex County, DE?
Sussex County is in Zone 7b with an average last frost of April 3. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sussex County, DE?
Sussex County, Delaware is in USDA Hardiness Zone 7b. The average last spring frost is April 3 and first fall frost is November 7.
Your Sussex County Garden Planner — Free
A 24-page printable planner built for Sussex 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.