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When to Plant Turnip in Maricopa County, AZ

Maricopa County, Arizona Zone 9b May

May to-do list for Maricopa County, Arizona

May is a pivotal month for Maricopa County, Arizona gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost January 31
Avg. first frost December 6
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs

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Turnips are a fast-growing cool-season root vegetable with edible roots and greens. Baby turnips are sweet and tender while mature ones are more pungent.

Maricopa County, Arizona is in USDA Zone 9b. The average last spring frost is January 31 and the first fall frost is December 6, giving you a growing season of approximately 309 days.

At an elevation of 4,014 feet, Maricopa County receives approximately 12.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 108°F, so Turnip may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Turnip will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Turnip successfully. Mulch heavily to conserve soil moisture.

Maricopa County, AZ (Zone 9b) Year-round
309 days
Last Spring Frost January 31
309 growing days
First Fall Frost December 6

Maricopa County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.2-8.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (241 days to spare)
Transplant: Jan 17 🍅 Harvest: Feb 28 – Apr 4
Recommended (50%) ✓ Fits season (232 days to spare)
Transplant: Jan 31 🍅 Harvest: Mar 14 – Apr 18
Safe Start (90%) ✓ Fits season (227 days to spare)
Transplant: Feb 27 🍅 Harvest: Apr 10 – May 15

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 Maricopa County

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

Soil pH

Your soil pH (7.2–8.5) is more alkaline than Turnip prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Turnip.

How to Plant Turnip

0.5"
Planting Depth
4"
Between Plants
12"
Between Rows

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

Succession Planting Turnip

9
successive plantings in your 309-day season

Sow every 4.6 weeks. Last sowing by Oct 07 to harvest before frost.

For a dedicated fall crop, sow by Oct 11.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.2″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 2,750 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Turnip

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

Month Turnip Needs Rainfall You Supplement Action
Jan 4.3" 0.9" 3.4" 🚿 Regular watering
Feb 4.3" 0.8" 3.5" 🚿 Regular watering
Mar 4.3" 0.7" 3.6" 🚿 Regular watering
Apr 4.3" 0.5" 3.8" 🚿 Regular watering
May 4.3" 0.3" 4" 🚿 Regular watering
Jun 4.3" 0.4" 3.9" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 4.3" 0.6" 3.7" 🚿 Regular watering
Dec 4.3" 0.8" 3.5" 🚿 Regular watering

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

Turnip 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.

Turnip needs ~1,550 GDD — county provides 9,610 GDD Excellent fit

Turnip Planting Timeline — Maricopa County, AZ

Turnip Planting Calendar

Activity When Date Range
Direct Sow January 10 Jan 10 – Jan 31
Harvest February 21 Feb 21 – Mar 28
Fall Sowing October 11 Oct 11 – Oct 25

Plant 0.5" deep · 4" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

309 days in Maricopa County

Growing Tips for Turnip in Maricopa County

Direct sow Turnip outdoors after January 31 in Maricopa County when soil has warmed and frost danger has passed.

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

With summer highs reaching 108°F in Maricopa County, provide afternoon shade for Turnip and water deeply in the morning.

Your generous 310.0-day season in Maricopa County allows multiple plantings of Turnip. Sow every 20.0 days for continuous harvest.

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

General growing tips

Direct sow in early spring or late summer. Harvest when roots are 2-3 inches in diameter for best flavor. Both the roots and the greens are nutritious and edible.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Turnip in Maricopa County, AZ?

Maricopa County is in Zone 9b with an average last frost of January 31. Plan your Turnip planting based on this frost date — see the calendar above for exact timing.

What planting zone is Maricopa County, AZ?

Maricopa County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is January 31 and first fall frost is December 6.

🌱

Your Maricopa County Garden Planner — Free

A 24-page printable planner built for Maricopa County (Zone 9b). 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 Maricopa County, AZ. 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.