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When to plant Foxglove in New Castle County County,

Plant Foxglove in New Castle County County, when soil hits 50°F — usually April 13. Continue planting through May 4 for the spring crop.

When to Plant Foxglove in New Castle County, DE

New Castle County, Delaware Zone 7b June

Your June gardening checklist

Each item below is timed to New Castle County, Delaware's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 6
Avg. first frost October 31
Soil temp (4") 76°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
  1. Start foxglove under lights

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Basket week: foxglove

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

July will be here before you know it — start on
  • First harvests: foxglove

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Foxglove (Digitalis purpurea) is a stately cottage garden classic, sending up dramatic 3–5 foot spires of tubular flowers — spotted purple, pink, white, or cream — in late spring and early summer. Technically biennial (flowering in its second year), foxglove perpetuates itself so freely from self-sown seed that established plantings appear to be permanent perennials. A key source plant for the heart medication digitalis, all parts are highly toxic if ingested. Bumblebees are the primary pollinators, crawling deep into each bell-shaped flower. Partial shade and cool, moist woodland-edge conditions suit foxglove best; it resents heat and drought.

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 Foxglove during the growing season.

Perennial Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
New Castle County, DE (Zone 7b) Long season
208 days
Last Spring Frost April 6
208 growing days
First Fall Frost October 31
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New Castle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-7.1

Drainage

Well Drained

Foxglove Planting Risk Windows

Early Start (70% safe) ✓ Fits season (120 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🌸 Bloom: May 23 – Jun 27
Recommended (50%) ✓ Fits season (117 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🌸 Bloom: Jun 1 – Jul 6
Safe Start (90%) ✓ Fits season (105 days to spare)
Start indoors: Mar 5 Transplant: May 7 🌸 Bloom: Jun 25 – Jul 30

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 Foxglove's growing requirements.

Soil pH

Your soil pH (5.2–7.1) overlaps with Foxglove's range (5.5–6.5), though not a perfect match.

Soil Texture

The silt loam soil in New Castle County is excellent for Foxglove — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Foxglove.

How to Plant Foxglove

0.1"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Foxglove

3
successive plantings in your 208-day season

Sow every 9.1 weeks. Last sowing by Jul 03 to harvest before frost.

Foxglove Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 427 gal / 100 sq ft

Monthly Watering Guide for Foxglove

Foxglove needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Foxglove Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
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.

Foxglove 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.

Foxglove needs ~1,675 GDD — county provides 3,484 GDD Excellent fit

Foxglove Planting Timeline — New Castle County, DE

Foxglove Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 13 Apr 13 – May 4
Bloom June 1 Jun 1 – Jul 6

Plant 0.1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May Direct Sow
June Bloom
July Bloom
August
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

208 days in New Castle County

Growing Tips for Foxglove in New Castle County

Direct sow Foxglove outdoors after April 06 in New Castle County when soil has warmed and frost danger has passed.

General growing tips

Sow seeds indoors 8–10 weeks before last frost or direct-sow outdoors in late spring/early summer for next-year bloom (biennial cycle). Surface-sow — seeds need light to germinate. Transplant after last frost into cool, moist, well-amended soil. Morning sun with afternoon shade is ideal; full shade reduces bloom but is tolerated. Keep consistently moist. First-year plants form a basal rosette only; second-year plants produce flower spikes. After bloom, cut the main spike before seed scatters to prevent excessive spreading, or leave some spikes to self-seed for naturalizing. Perennial species (D. grandiflora, D. x mertonensis) maintain clumps without requiring self-seeding. Wear gloves when handling — all plant parts toxic.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Foxglove in New Castle County, DE?

New Castle County is in Zone 7b with an average last frost of April 6. Plan your Foxglove 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 Foxglove in New Castle County County, ?

In New Castle County County, , plant Foxglove 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 Foxglove?

New Castle County County sits in USDA Zone 7b. Foxglove grows reliably in zones 3a through 9a, so it's a good fit here.

Can Foxglove grow in New Castle County County's climate?

Yes — Foxglove 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for New Castle County, DE. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.