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When to Plant Romanesco in Hillsborough County, FL

Hillsborough County, Florida Zone 10a May

What to do in May

We've pulled the most time-sensitive tasks for Hillsborough County, Florida this May and put them front and centre. Tackle them in order.

Avg. last frost January 25
Avg. first frost December 20
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Bring in the romanesco

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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Romanesco is a stunning brassica with a lime-green head composed of fractal-patterned spiraling florets. It has a nuttier, milder flavor than cauliflower.

Hillsborough County, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 20, giving you a growing season of approximately 329 days.

At an elevation of 63 feet, Hillsborough County receives approximately 54.4 inches of rainfall annually with predominantly sand soil. Summer highs average 98°F, so Romanesco may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Romanesco will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Romanesco root diseases.

Hillsborough County, FL (Zone 10a) Year-round
329 days
Last Spring Frost January 25
329 growing days
First Fall Frost December 20

Hillsborough County Soil Profile

Soil Type

Sand

Soil pH

4.9-5.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (207 days to spare)
Start indoors: Dec 20 Transplant: Jan 17 🍅 Harvest: Apr 4 – May 16
Recommended (50%) ✓ Fits season (210 days to spare)
Start indoors: Dec 28 Transplant: Jan 25 🍅 Harvest: Apr 12 – May 24
Safe Start (90%) ✓ Fits season (186 days to spare)
Start indoors: Jan 26 Transplant: Feb 23 🍅 Harvest: May 11 – Jun 22

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 Hillsborough County

How your county's soil matches Romanesco's growing requirements.

Soil pH

Your soil pH (4.9–5.9) is more acidic than Romanesco prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Hillsborough County warms quickly in spring but drains fast. Romanesco will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Romanesco.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting Romanesco.

How to Plant Romanesco

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Romanesco

5
successive plantings in your 329-day season

Sow every 8.6 weeks. Last sowing by Sep 11 to harvest before frost.

For a dedicated fall crop, sow by Oct 25.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 2,142 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Romanesco

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

Month Romanesco Needs Rainfall You Supplement Action
Jan 4.3" 2.3" 2" 💧 Light watering
Feb 4.3" 2.7" 1.6" 💧 Light watering
Mar 4.3" 2.9" 1.4" 💧 Light watering
Apr 4.3" 2.1" 2.2" 🚿 Regular watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 8.1" 0" ✅ Rainfall sufficient
Jul 4.3" 8" 0" ✅ Rainfall sufficient
Aug 4.3" 8" 0" ✅ Rainfall sufficient
Sep 4.3" 7.7" 0" ✅ Rainfall sufficient
Oct 4.3" 4.5" 0" ✅ Rainfall sufficient
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 4.3" 2.4" 1.9" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Hillsborough County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Romanesco 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.

Romanesco needs ~2,056 GDD — county provides 7,755 GDD Excellent fit

Romanesco Planting Timeline — Hillsborough County, FL

Romanesco Planting Calendar

Activity When Date Range
Start Indoors December 28 Dec 28 – Jan 11
Transplant Outdoors January 25 Jan 25 – Feb 8
Direct Sow January 4 Jan 4 – Jan 25
Harvest April 12 Apr 12 – May 24
Fall Sowing October 25 Oct 25 – Nov 8

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 10a

📆 Growing Season

329 days in Hillsborough County

Growing Tips for Romanesco in Hillsborough County

Direct sow Romanesco outdoors after January 25 in Hillsborough County when soil has warmed and frost danger has passed.

Sandy soil in Hillsborough County dries quickly — mulch Romanesco with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 98°F in Hillsborough County, provide afternoon shade for Romanesco and water deeply in the morning.

Common pests for Romanesco in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 5-7 weeks before transplanting. Provide consistent moisture and avoid temperature stress. Harvest when head is fully formed but before florets begin to separate.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Romanesco in Hillsborough County, FL?

Hillsborough County is in Zone 10a with an average last frost of January 25. Plan your Romanesco planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hillsborough County, FL?

Hillsborough County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 25 and first fall frost is December 20.

🌱

Your Hillsborough County Garden Planner — Free

A 24-page printable planner built for Hillsborough County (Zone 10a). 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 Hillsborough County, FL. Local conditions may vary. Last updated: May 2026.

Sources & credits

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