Plants
Timing your beet planting in Colorado isn’t just about the calendar—it’s about elevation, frost dates, and knowing when those 🍠 roots will thrive. Get it wrong, and you’ll end up with bitter greens instead of sweet harvests. The key? Planting in the 60-day window before your first frost, adjusted for whether you’re in Denver’s lowlands or the mountains.
Most Colorado gardeners in zones 5-7 can start beets as early as March 15 in lowland areas, but high-altitude growers should wait until April 15 to avoid frost damage. The secret to success? Two planting cycles—spring for June harvests and fall for October feasts—while accounting for Colorado’s unpredictable weather shifts.
I’ll show you exactly when to sow seeds by elevation, how to stretch your growing season with row covers, and which beet varieties handle Colorado’s cool nights and hot days best. No more guessing—just a foolproof plan for the garden you’ve been dreaming of.
Let’s dive into the frost-free windows that’ll transform your Colorado garden into a beet bonanza, no matter where you live in the state.
Colorado beet planting calendar by elevation zone (lowland to mountain)
Colorado’s dramatic elevation shifts—from the Front Range to mountain valleys—mean your beet planting schedule should match your altitude. Lowland areas like Denver (5,000–6,500 ft) have longer growing seasons, while high-altitude gardens (8,000+ ft) face shorter frost-free windows.
Get your timing wrong, and you’ll end up with bitter, woody beets or plants that bolt before harvest.
Beets thrive in cool weather (50–75°F), making spring and fall the ideal planting windows. In Colorado, this translates to two key periods: March–April for spring crops and August–September for fall harvests. But your exact dates depend on whether you’re gardening in Pueblo, Fort Collins, or Aspen.
Here’s how to align your planting with Colorado’s three major elevation zones, including last frost dates and ideal soil temperatures for germination:
For Front Range gardeners, aim to sow seeds 4–6 weeks before your last frost—typically by March 15. This gives beets time to mature before summer heat sets in.
In Denver or Colorado Springs, you can even squeeze in a late summer crop by planting around August 15 for a fall harvest before frost.
In higher elevations like Fort Collins or Boulder, wait until April 1 to avoid late frosts. Use black plastic mulch to warm the soil faster if needed.
Mountain gardeners (e.g., Aspen or Leadville) should focus on fast varieties like ‘Detroit Dark Red’, which mature in 50–55 days—critical for short seasons.
Pro tip: Check your local Cooperative Extension office for hyper-local frost dates. Even within 100 miles, frost timing can vary by 2–3 weeks. For example, Greeley’s last frost often comes 10 days earlier than Golden’s.
Once you’ve nailed your planting window, the next challenge is extending your harvest. In Colorado’s unpredictable climate, a late frost or early heatwave can derail your plans. That’s why succession planting and season-extending tools are your best friends—we’ll cover those strategies in the next section.
Colorado beet planting calendar by elevation zone (lowland to mountain)
Colorado’s elevation zones dramatically impact your beet planting schedule. Lowland areas (5,000-6,500 ft) like Denver have longer growing seasons, while mountain regions (8,000+ ft) face shorter frost-free windows. Understanding these differences ensures you plant at the perfect time for tender, sweet beets.
For Front Range gardeners (5,000-6,500 ft), the ideal window is March 15 to April 30 for spring plantings and August 15 to September 15 for fall crops.
These dates align with average last frost dates of April 15 and first frost dates of October 15, giving you a 160-day growing season.
Foothills (6,500-8,000 ft) experience cooler temperatures, so adjust your timing slightly. Start seeds April 1 to May 15 for spring and July 30 to August 30 for fall. Mountain regions (8,000+ ft) have even shorter seasons, with May 1 to June 15 for spring and July 15 to August 15 for fall plantings.
| Elevation Zone | Last Frost | Spring Planting Window | Fall Planting Window | Frost-Free Days |
|---|---|---|---|---|
| Front Range (5,000-6,500 ft) | April 15 | March 15 - April 30 | August 15 - September 15 | 160 days |
| Foothills (6,500-8,000 ft) | May 1 | April 1 - May 15 | July 30 - August 30 | 140 days |
| Mountain Regions (8,000+ ft) | May 15 | May 1 - June 15 | July 15 - August 15 | 120 days |
Soil temperature is another critical factor. Beets thrive when soil reaches at least 50°F (10°C). In mountain regions, wait until late May when soil warms sufficiently. Use a soil thermometer to check—cold soil delays germination and leads to poor growth.
For fall plantings, aim to harvest before hard frosts. In lowland areas, beets planted by September 15 will mature before the first frost. In higher elevations, start seeds by August 15 to ensure a harvest before October’s chill sets in.
Pro tip: Use succession planting every 2 weeks in spring and fall to maintain a steady harvest. This works especially well in lowland areas where the growing season is longer.