Growing Heirloom Tomatoes in Colorado: What Actually Works

Colorado gardeners kill more tomato plants than anyone will admit.

The problem isn't skill. It's the environment. Short season. Late frosts. Intense afternoon sun. Hail in June. Temperature swings that would break a tomato that was selected for a gentler climate.

The good news: the right varieties, started right, planted at the right time, absolutely thrive at Front Range altitude. Here's what I've learned after 20+ years of growing in Arvada.

Start With the Right Variety

Most big-box tomato starts are bred for the Southeast or the Pacific Northwest — long seasons, mild nights, reliable heat. That's not our life.

For Colorado, you want varieties that:

• Ripen in 80 days or fewer (for a reliable harvest before first fall frost)
• Tolerate cold nights (altitude means nights that drop fast even in summer)
• Have strong root systems (for the heat-stressed, fast-draining soils common on the Front Range)

Best early varieties for Colorado:

• Stupice (55 days) — Czech heirloom, cold-tolerant, first ripe every year
• Gold Nugget Cherry (60 days) — prolific producer with a short window to maturity
• Gardener's Delight (65 days) — sweet cherry, reliable at altitude

If you want the big heirlooms — Brandywine, Cherokee Purple, Black Krim — you can still grow them. You just have to start them early (indoors in late February or early March) and be patient.

Understand Your Frost Dates

Arvada and the Five Parks area typically sees:

• Last spring frost: Mid-May (sometimes as late as Memorial Day weekend)
• First fall frost: Early to mid-October

That gives you roughly 140–150 growing days — enough for any variety under 90 days to maturity if you start from healthy starts (not seeds direct-sown).

Don't transplant before soil temps hit 60°F. Cold soil stops root development regardless of air temperature.

Harden Off Before Planting

If your starts have been indoors or in a greenhouse, they need 7–10 days of gradual outdoor exposure before they go in the ground. Start with a few hours of morning sun. Increase daily. Skip hardening off and you risk transplant shock that sets you back 2–3 weeks.

Plants from Maske's Fresh Start Greens are already hardened off before pickup. That's one less variable.

Water Deeply and Infrequently

Colorado's low humidity and intense sun mean surface water evaporates fast. Water at the base, not overhead. Water deeply 2–3 times per week rather than a little every day. Inconsistent watering is the primary cause of blossom end rot and fruit cracking on heirlooms.

Drip irrigation or soaker hoses are the most reliable setup for Front Range gardens.

Protect From Hail

Front Range hail is real and it doesn't care about your Cherokee Purple. Keep floating row cover on hand — the kind that allows light through — or have a plan for quick coverage during storm season (May through early August).

A tomato cage with row cover thrown over it works fine. It's not pretty, but neither is hail damage.

The Varieties Worth Growing in Colorado

After 20+ seasons on the Front Range, these are the ones that deliver:

• Early slicers: Stupice, Early Girl (hybrid), Bush Early Girl
• Cherry: Gold Nugget, Gardener's Delight, Matt's Wild Cherry, Sun Sugar
• Mid-season slicers: Green Zebra, Kellogg's Breakfast, Paul Robeson
• Late-season beefsteaks: Cherokee Purple, Black Krim, Pink Brandywine
• Paste: Roma, San Marzano

The heirlooms take longer. They're worth it. Just start them early and give them the time they need.

Where to Get Altitude-Tested Starts in Arvada

Maske's Fresh Start Greens grows 20+ heirloom varieties at our home in Arvada, Colorado — selected specifically for Front Range conditions. We start seeds in late February, harden plants off before pickup, and open for pre-orders every spring.

We sell out every year. If you want to guarantee your plants, pre-order early.

Pre-Order 2026 Heirloom Tomato Plants → See All Varieties →

Matt Maske is a Colorado-based gardener and the founder of Maske's Fresh Start Greens in Arvada. He has grown vegetables on the Front Range for 20+ years.