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When to Plant Romanesco in Linn County, MO

Linn County, Missouri Zone 6a May

Your May gardening checklist

Here's what deserves your attention in Linn County, Missouri this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 17
Avg. first frost October 20
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Sow romanesco in trays indoors

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

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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.

Linn County, Missouri is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 20, giving you a growing season of approximately 186 days.

At an elevation of 880 feet, Linn County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Romanesco during the growing season.

Linn County, MO (Zone 6a) Moderate season
186 days
Last Spring Frost April 17
186 growing days
First Fall Frost October 20

Linn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jun 27 – Aug 8
Recommended (50%) ✓ Fits season (67 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jul 3 – Aug 14
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 16 – Aug 27

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 Linn County

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

Soil pH

Your soil pH (5.5–6.8) overlaps with Romanesco's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Romanesco.

How to Plant Romanesco

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Romanesco

2
successive plantings in your 186-day season

Sow every 8.6 weeks. Last sowing by Jul 12 to harvest before frost.

For a dedicated fall crop, sow by Aug 11.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 533 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 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Linn 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 ~1,203 GDD — county provides 2,557 GDD Excellent fit

Romanesco Planting Timeline — Linn County, MO

Romanesco Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors April 17 Apr 17 – May 1
Direct Sow April 3 Apr 3 – Apr 24
Harvest July 3 Jul 3 – Aug 14
Fall Sowing August 11 Aug 11 – Aug 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

186 days in Linn County

Growing Tips for Romanesco in Linn County

Direct sow Romanesco outdoors after April 17 in Linn County when soil has warmed and frost danger has passed.

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 Linn County, MO?

Linn County is in Zone 6a with an average last frost of April 17. Plan your Romanesco planting based on this frost date — see the calendar above for exact timing.

What planting zone is Linn County, MO?

Linn County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 20.

🌱

Your Linn County Garden Planner — Free

A 24-page printable planner built for Linn County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Linn County, MO. 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.