When to plant · 22 cities · zones 5b–7a

When to plant peppers in Colorado

Start Jalapeño seeds indoors around Mar 12 and transplant around May 14 — the Colorado statewide median, counted from a last spring frost of May 7 across 493 ZIP codes and 190 NOAA stations.

Mar 12Start indoors8 weeks before last frost
May 14Plant outMay 7 – Jun 13 across the state
May 7Last spring frostmedian · 1 in 10 years after May 21
Jul 28First harvest75 days from transplant

The rule: Eight weeks indoors on a heat mat (ten for habanero), then transplant one to two weeks after the last frost, once nights hold above 50 °F.

Colorado peppers, by cultivar

Statewide median last frost May 7, first fall frost Oct 6, 2027 season. Each cultivar's own indoor lead time and days to maturity, same engine as the Plan Builder.

CultivarStart indoorsPlant outFirst harvestDays
JalapeñoEarly Jalapeño (Capsicum annuum)Mar 12May 14Jul 2875 from transplant
CayenneLong Slim Cayenne (Capsicum annuum)Mar 12May 14Jul 2875 from transplant
SerranoSerrano Tampiqueño (Capsicum annuum)Mar 12May 14Aug 280 from transplant
Marconi Red PepperMarconi Red (Capsicum annuum)Mar 12May 14Aug 280 from transplant
HabaneroOrange Habanero (Capsicum chinense)Feb 26May 21Aug 2495 from transplant

Tight means first harvest lands within two weeks of the median first fall frost. Statewide dates are the ZIP-weighted median of every NOAA 1991–2020 station Colorado's ZIP codes resolve to; 34 of 527 ZIPs have no datable freeze and are left out.

Peppers in Colorado, city by city

Jalapeño, scheduled from each city's nearest NOAA station — the same dates as its frost page.

CityLast frostStart indoorsPlant outFirst harvest
Denverzone 6aMay 4Mar 9May 11Jul 25
Colorado Springszone 6aMay 3Mar 8May 10Jul 24
Aurorazone 6aMay 5Mar 10May 12Jul 26
Fort Collinszone 5bMay 3Mar 8May 10Jul 24
Lakewoodzone 6aMay 3Mar 8May 10Jul 24
Thorntonzone 6aMay 2Mar 7May 9Jul 23
Arvadazone 6aMay 5Mar 10May 12Jul 26
Westminsterzone 6aMay 2Mar 7May 9Jul 23
Greeleyzone 5bMay 2Mar 7May 9Jul 23
Pueblozone 6aApr 26Mar 1May 3Jul 17
Centennialzone 6aMay 5Mar 10May 12Jul 26
Boulderzone 6aMay 6Mar 11May 13Jul 27
Longmontzone 5bMay 7Mar 12May 14Jul 28
Castle Rockzone 5bMay 9Mar 14May 16Jul 30
Lovelandzone 5bMay 3Mar 8May 10Jul 24
Broomfieldzone 6aMay 2Mar 7May 9Jul 23
Grand Junctionzone 7aApr 28Mar 3May 5Jul 19
Commerce Cityzone 6aMay 3Mar 8May 10Jul 24
Parkerzone 5bMay 9Mar 14May 16Jul 30
Littletonzone 6aMay 2Mar 7May 9Jul 23
Brightonzone 5bMay 3Mar 8May 10Jul 24
Windsorzone 5bMay 3Mar 8May 10Jul 24

What Colorado peppers need

SeedsThe cultivar decides the sauce. Everything downstream is damage control.
  • Jalapeño Pepper Seed

    The one you smoke into chipotle. Left on the plant to red and corked, then cold-smoked, a jalapeño stops being a taco garnish and becomes the backbone of an adobo.

  • Organic Cayenne (Long Slim) Seed

    The long, thin, wall-thin cayenne that dries in a week and grinds to a clean red powder. If you want flakes and powder as well as sauce, this is the plant that does both.

  • Serrano Pepper Seed

    Cleaner and greener than a jalapeño at roughly three times the heat. The correct chile for salsa verde and zhoug, where you want brightness rather than smoke.

  • Marconi Red Sweet Pepper Seed

    A long Italian sweet pepper that roasts and peels far better than a bell. Romesco and any red-pepper paste wants this, not a supermarket bell.

  • Habanero Orange Pepper SeedMust have

    The workhorse superhot for sauce: 100,000–350,000 SHU with a genuine apricot-floral top note that survives fermentation. Nothing else in this range tastes like fruit instead of pure burn.

StartSoil temperature and light intensity, indoors, weeks before your frost date.
  • Organic Seed Starter Potting MixMust have

    Seed-starting mix is not potting soil with a nicer label — it is finer, lighter, and low in nutrients on purpose, because a seedling's first roots want air and moisture, not fertiliser.

  • Seedling Heat Mat + Digital ThermostatMust have

    Peppers germinate on soil temperature, not air temperature. At 65 °F a habanero takes a month and half of them rot; at 85 °F it is up in eight days. The thermostat is the half that matters.

  • T8 Full-Spectrum Grow Lights, 1 ft 4-packMust have

    A south window in March delivers a fraction of the light a pepper seedling needs, and the plant tells you by stretching. Two inches of LED above the canopy for 16 hours a day fixes it permanently.

  • 72-Cell Trays with 1020 Bottoms, 5-PackMust have

    The cheap black nursery trays crack after one season and flex enough to break roots when you lift them. These do not. Over five seasons the price per use is lower than the throwaways.

GrowRoot volume, nutrition and structure. Where most home crops actually fail.
  • 5-Gallon Fabric Grow Bags, 5-Pack

    Fabric pots air-prune roots and drain faster than a plastic pot can, which is the entire reason container tomatoes fail. Five gallons is the honest minimum for a pepper; a tomato wants ten.

  • Ocean Forest Potting SoilMust have

    Pre-charged with enough nutrition to carry a transplant for its first month without feeding, which is exactly the window when most container plants stall.

  • Organic Tomato-Tone 3-4-6 with 8% CalciumMust have

    The NPK ratio is the point: low nitrogen, higher potassium. Feed a tomato a high-nitrogen lawn fertiliser and you get a magnificent six-foot plant with four tomatoes on it.

  • Rot-Stop Blossom End Rot Concentrate

    Blossom end rot is almost never a soil calcium shortage — it is a calcium *transport* failure caused by inconsistent water. A foliar calcium spray buys time while you fix the watering, which is the real cure.

HarvestTiming, handling, and weighing what you actually got.
  • 6" Micro-Tip Pruning SnipsMust have

    Ninety percent of sauce-garden cutting is snipping a pepper stem or a basil node, and a fine-tipped snip does it better than any pruner. Pulling peppers by hand tears the branch.

  • Nitrile Exam Gloves, 200 pcs, food-safeMust have

    Capsaicin is oil-soluble and does not wash off with soap. Seeding a pound of habaneros bare-handed means eight hours of burning hands and one unforgettable mistake involving your own eye.

CookReduction, texture, and the non-reactive pans that keep tomato tasting like tomato.
  • Pellet Smoker Tube, 12", Set of 2

    Chipotle is nothing but a red jalapeño that has been cold-smoked for hours. A pellet tube turns any covered grill into a cold smoker for eighteen dollars.

  • Food Dehydrator, 6 Stainless Trays

    Sun-drying chiles works in Oaxaca and fails in Ohio — humidity lets mould win the race. Controlled 125 °F airflow dries a full cayenne harvest overnight, every time.

  • One-Touch Coffee & Spice Grinder

    Dried cayenne into powder in fifteen seconds. Dedicate one to chiles — grind coffee in it afterwards and you will find out exactly how well capsaicin sticks to plastic.

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Peppers in Colorado: questions

When should I plant peppers in Colorado?

Transplant around May 14 at the statewide median; across the state that date runs from May 7 in the warmest tenth of Colorado's ZIP codes to Jun 13 in the coldest. To cut the freeze risk to one year in ten, count from May 21 instead of the median last frost. Use the city table for your own town.

When do I start peppers seeds indoors in Colorado?

Around Mar 12 for Jalapeño: 8 weeks before the statewide median last frost, on soil held at 75–85 °F.

When is the last frost in Colorado?

The ZIP-weighted median of NOAA 1991–2020 station medians is May 7. In the warmest tenth of Colorado's ZIP codes the median last frost falls on or before Apr 30; in the coldest tenth, on or after Jun 6.

When will Colorado peppers be ready to harvest?

Jalapeño planted on the statewide date is ready around Jul 28: 75 days from transplant.

More for Colorado

Peppers in every state → · Colorado frost dates → · How frost-date math works →