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When to Plant Beets in Mahaska County, IA

Mahaska County, Iowa Zone 5b May

What to do in May

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

Avg. last frost April 27
Avg. first frost October 9
Soil temp (4") 58°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
Get ahead of June
  • First harvests: beets

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Beets are a dual-purpose root vegetable with edible roots and nutritious greens. They come in red, golden, and striped varieties and are rich in vitamins and minerals.

Mahaska County, Iowa is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 9, giving you a growing season of approximately 165 days.

At an elevation of 511 feet, Mahaska County receives approximately 32.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Beets to ensure they mature before fall.

Mahaska County, IA (Zone 5b) Moderate season
165 days
Last Spring Frost April 27
165 growing days
First Fall Frost October 9

Mahaska County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 16 – Jul 14
Recommended (50%) ✓ Fits season (81 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 22 – Jul 20
Safe Start (90%) ✓ Fits season (77 days to spare)
Transplant: May 14 🍅 Harvest: Jul 9 – Aug 6

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 Mahaska County

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

Soil pH

Your soil pH (5.7–7.3) overlaps with Beets's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Beets will thrive.

How to Plant Beets

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

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

Succession Planting Beets

3
successive plantings in your 165-day season

Sow every 5.7 weeks. Last sowing by Jul 31 to harvest before frost.

For a dedicated fall crop, sow by Jul 31.

Plant Water Budget

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

Monthly Watering Guide for Beets

Beets needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Beets Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.5" 3.1" 0.4" 💧 Light watering
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 4.5" 0" ✅ Rainfall sufficient
Jul 3.5" 3.3" 0.2" 💧 Light watering
Aug 3.5" 3.2" 0.3" 💧 Light watering
Sep 3.5" 3.2" 0.3" 💧 Light watering
Oct 3.5" 2.4" 1.1" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Beets 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.

Beets needs ~735 GDD — county provides 2,021 GDD Excellent fit

Beets Planting Timeline — Mahaska County, IA

Beets Planting Calendar

Activity When Date Range
Direct Sow April 13 Apr 13 – May 4
Harvest June 8 Jun 8 – Jul 6
Fall Sowing July 31 Jul 31 – Aug 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

165 days in Mahaska County

Growing Tips for Beets in Mahaska County

Direct sow Beets outdoors after April 27 in Mahaska County when soil has warmed and frost danger has passed.

General growing tips

Soak seeds overnight before planting to improve germination. Thin seedlings to 3-4 inches apart. Harvest roots when 1.5-3 inches in diameter for best texture.

Companion Planting

Good Companions

Avoid Planting Near

  • Pole Beans
  • Mustard Greens

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Beets Seeds
Life Cycle Biennial
Pollination Wind Pollinated
How to Collect Replant roots for 2nd-year seeds. Rub stalks to free clusters.
Storage Store airtight; viable 6 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Swiss chard — same species, they will cross.

Frequently Asked Questions

When should I plant Beets in Mahaska County, IA?

Mahaska County is in Zone 5b with an average last frost of April 27. Plan your Beets planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mahaska County, IA?

Mahaska County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 9.

🌱

Your Mahaska County Garden Planner — Free

A 24-page printable planner built for Mahaska County (Zone 5b). 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 Mahaska County, IA. 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.