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When to Plant Beets in Boulder County, CO

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.

Boulder County, Colorado is in USDA Zone 5b. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 7,657 feet, Boulder County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Beets during the growing season.

Boulder County, CO (Zone 5b) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Boulder County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (56 days to spare)
Transplant: May 3 🍅 Harvest: Jun 28 – Jul 26
Recommended (50%) ✓ Fits season (51 days to spare)
Transplant: May 14 🍅 Harvest: Jul 9 – Aug 6
Safe Start (90%) ✓ Fits season (44 days to spare)
Transplant: Jun 10 🍅 Harvest: Aug 5 – Sep 2

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 Boulder County

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

Soil pH

Your soil pH (6.7โ€“8.0) overlaps with Beets's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Boulder County is excellent for Beets โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Beets.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Beets.

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 135-day season

Sow every 5.7 weeks. Last sowing by Jul 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 18.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 504 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Beets needs ~870 GDD — county provides 1,957 GDD Excellent fit

Beets Planting Timeline โ€” Boulder County, CO

Beets Planting Calendar

Activity When Date Range
Direct Sow April 30 Apr 30 โ€“ May 21
Fall Sowing July 18 Jul 18 โ€“ Aug 1
Harvest June 25 Jun 25 โ€“ Jul 23

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

135 days in Boulder County

Growing Tips for Beets in Boulder County

Direct sow Beets outdoors after May 14 in Boulder 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

Level Up Your Garden

๐ŸŒพ 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 35ยฐF, under 50% humidity.

Isolate 1/2 mile from Swiss chard โ€” same species, they will cross.

Frequently Asked Questions

When should I plant Beets in Boulder County, CO?

Boulder County is in Zone 5b with an average last frost of May 14. Plan your Beets planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Boulder County, CO?

Boulder County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Boulder County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Boulder County, CO. Local conditions may vary. Last updated: April 2026.