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When to plant Celosia in New Castle County, DE

New Castle County's climate puts the Celosia spring window between April 6 and April 27. most warm-season crops establish quickly once soil holds above 60°F.

When to Plant Celosia in New Castle County, DE

New Castle County, Delaware Zone 7b June

Your June planting checklist for New Castle County, Delaware

We've pulled the most time-sensitive tasks for New Castle County, Delaware this June and put them front and centre. Tackle them in order.

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. Collect celosia at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this June that'll pay off in July
  • First harvests: celosia

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Celosia (Celosia argentea) encompasses the vivid cockscomb (cristata) and feathery plumed (plumosa) types that explode with color in summer heat. Drought-tolerant and disease-resistant, they thrive in the hottest parts of the season and produce long-lasting blooms both in the garden and as cut or dried flowers. A reliable filler in sunny annual beds.

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 Celosia during the growing season.

Annual Blooms in Summer Pollinator-friendly 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

New Castle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-7.1

Drainage

Well Drained

Celosia Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 28 Transplant: Mar 28 🌸 Bloom: May 30 – Oct 10
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🌸 Bloom: Jun 8 – Oct 19
Safe Start (90%) ✓ Fits season (0 days to spare)
Start indoors: Apr 2 Transplant: Apr 30 🌸 Bloom: Jul 2 – Nov 12

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 Celosia's growing requirements.

Soil pH

Your soil pH (5.2–7.1) overlaps with Celosia's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Celosia

0.1"
Planting Depth
9"
Between Plants
12"
Between Rows

Succession Planting Celosia

4
successive plantings in your 208-day season

Sow every 6.9 weeks. Last sowing by Aug 02 to harvest before frost.

Celosia Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Celosia

Celosia 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 Celosia Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 2.2" 3.2" 0" ✅ Rainfall sufficient
May 2.2" 3.3" 0" ✅ Rainfall sufficient
Jun 2.2" 3.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 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.

Celosia 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.

Celosia needs ~1,256 GDD — county provides 3,484 GDD Excellent fit

Celosia Planting Timeline — New Castle County, DE

Celosia Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow April 6 Apr 6 – Apr 27
Bloom June 8 Jun 8 – Oct 19

Plant 0.1" deep · 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

208 days in New Castle County

Growing Tips for Celosia in New Castle County

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

General growing tips

Start seeds indoors 4–6 weeks before last frost, or direct-sow after soil warms above 60°F. Does not transplant well from large pots — sow in small cells or direct-sow. Needs full sun and warm soil; cold stress causes stunting. Pinch first bloom to encourage branching. Water at the base; wet foliage encourages fungal issues. Excellent dried flower — harvest before seeds set for the best color retention.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

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

In New Castle County, DE, plant Celosia 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, DE for Celosia?

New Castle County sits in USDA Zone 7b. Celosia grows reliably in zones 3a through 11b, so it's a good fit here.

Can Celosia grow in New Castle County's climate?

Yes — Celosia grows well in New Castle County's temperate climate. New Castle 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.