- Colorado grow guide · Updated November 12, 2026
Marijuana Seeds in Colorado
Adults 21 and over in Colorado can grow up to 6 cannabis plants, no more than 3 of them flowering at once, and no more than 12 per home. Plants must be in an enclosed, locked space, and state health guidance says they can’t be outside, so most home grows are indoors. No permit is needed.
- Legal age
- 21+
- Plants per adult
- 6, up to 3 flowering
- Plants per home
- 12
- Permit needed
- No
- Where
- Enclosed, locked, not outside
- Possession
- Up to 2 oz
- USDA zones
- 3b–7b
Colorado home-grow rules
What adults 21 and over may grow and keep under Amendment 64 (Colorado Constitution art. XVIII, § 16) and C.R.S. 18-18-406. Home-grow limits haven’t changed in 2025 or 2026.
| Who can grow | Adults 21 and over. |
|---|---|
| Plants per adult | Up to 6, with no more than 3 mature, flowering plants at a time. |
| Plants per home | No more than 12 on a residential property, however many adults live there, unless your city or county expressly allows more. Any plant over 4 inches tall or wide, or any flowering plant, counts. |
| Where plants must be kept | In an enclosed, locked space: covered and surrounded on all sides and locked at every entry. State health guidance says plants can’t be openly viewable and can’t be outside. |
| If under-21s live with you | The grow must be in its own enclosed, locked space they can’t get into. If no one under 21 lives there, the home’s outside locks count, but restrict access when under-21s visit. |
| Permit or registration | None for adult-use home grow. |
| What you can keep | Up to 2 ounces. You may also keep what your own plants produce on the premises where they grew. |
| Selling | Homegrown cannabis can’t be sold. Only licensed businesses may sell cannabis. |
| Landlords and property owners | May ban or regulate growing on property they own or control. |
| Local rules | Cities and counties can set stricter home-grow rules, so check your local law. |
| Medical patients | Registered patients may grow 6 plants, 3 or fewer mature. The 12-per-residence cap still applies, apart from a narrow exception for some patients and caregivers. |
| Regulators | Colorado Department of Public Health and Environment (home-grow guidance) and the Marijuana Enforcement Division (stores) |
Growing cannabis in Colorado
Colorado’s rules push home grows indoors. Here’s what that means for your setup, and what the climate does to anything that relies on the sun.
Indoors is the clear choice
State health guidance says home-grown plants must be in an enclosed, locked space and can’t be outside. A locked room, closet or grow tent behind locked doors meets the rule most plainly.
Covered structures
State law defines “enclosed” as covered and surrounded on all sides. No state page says whether a locked greenhouse qualifies, so check your local rules first.
Season and frost
The average last frost is about May 10–15 on the Front Range and April 20–22 in the Grand Valley. The first freeze comes in early to mid October on the Front Range, late October in the Grand Valley, and early September in high mountain valleys.
What to watch for in Colorado
- Three flowering plants at a time. Autoflowers start flowering on their own, so plant them in batches to stay within the limit.
- Early fall freezes. The plains and Front Range average a first freeze in early to mid October, and high valleys in early September.
- Hail. Severe hail peaks in mid-June, and eastern Colorado, including the Front Range, gets far more severe storms than the Western Slope.
- Dry air and strong sun. Low humidity, drying winds and intense high-elevation sun, plus alkaline soils with a pH up to 8.5.
How Colorado’s regions differ
The Grand Valley around Grand Junction and Palisade (zone 7a) has the warmest, longest season, about 183 frost-free days. Front Range cities (zone 6a) get about 150–155. The eastern plains are colder in winter and more hail-prone, and high mountain towns (zones 3b–5a) have very short seasons, about 25 frost-free days at Leadville.
Strains that suit Colorado
Chosen for indoor grows under Colorado’s 3-flowering-plant limit, using Beaver Seeds’ researched strain data: feminized strains you can switch to flower when you choose, and autoflowers you can grow in batches.
- Blue Dream: flowers in about 9–10 weeks once you switch your lights to 12 hours a day, so you decide when your 3 flowering plants start.
- Bruce Banner 2.0: flowers in about 8–10 weeks indoors after the switch to 12 hours of light.
- Runtz Auto: seed to harvest in about 9–10 weeks. Plant in batches of 3 to stay within the flowering limit.
- Zkittlez Auto: seed to harvest in about 8–12 weeks, so a second batch can start as the first one finishes.
Buying marijuana seeds in Colorado
How Beaver Seeds orders reach Colorado, and what state law says about buying seeds there.
Shipped from our US warehouse
US orders ship by USPS in plain, unbranded packaging. Priority Mail usually arrives in 3–7 days and Ground Advantage in 3–14 days. Shipping is free over $200.
Buy 1, get 1 free
Buy a 10 or 25 seed pack and get a second pack of the same size free, in any strain. 5-seed packs come with 1 extra seed.
80% germination guarantee
Every pack is covered. If your seeds don’t sprout as they should, contact our support team with your order number and we’ll help.
Licensed Colorado retail stores may sell seeds and immature plants (clones up to 15 inches tall or wide) to adults 21 and over, with up to 6 seeds per transaction on top of the 1-ounce limit. Colorado hasn’t published guidance on buying seeds online or from out of state.
Colorado grow FAQ
Short answers to the questions Colorado growers ask most.
Is it legal to grow marijuana at home in Colorado?
Yes. Adults 21 and over may grow up to 6 plants, no more than 3 of them flowering, with a cap of 12 per residence, in an enclosed, locked space. No permit is needed.
Can I grow cannabis outside in Colorado?
State health guidance says home-grown plants can’t be outside. The law requires an enclosed, locked space that is covered and surrounded on all sides, and it doesn’t say whether a locked greenhouse counts, so check your local rules.
Do autoflowers work under the 3-flowering-plant rule?
Yes, if you stagger them. Autoflowers start flowering on their own a few weeks after sprouting, so plant them in batches to keep no more than 3 in flower at once.
How many plants can a household grow in Colorado?
No more than 12 on a residential property, however many adults live there, unless your city or county expressly allows more.
Can my landlord stop me from growing in Colorado?
Yes. Landlords and other property owners may ban or regulate growing on property they own or control.
Sources
- Home grow laws (Colorado Department of Public Health and Environment)
- Laws about cannabis use (Colorado Department of Public Health and Environment)
- Business and property owners (Colorado Department of Public Health and Environment)
- C.R.S. 18-18-406, offenses relating to marijuana (Colorado statutes (public.law reproduction))
- HB21-1090, criminal marijuana offenses (Colorado General Assembly)
- Colorado Marijuana Rules, 1 CCR 212-3 (Marijuana Enforcement Division)
- Average last spring frost and freeze dates (NOAA National Weather Service, Grand Junction)
- First fall freezes (Colorado Climate Center, Colorado State University)
- Colorado gardening: challenge to newcomers (Colorado State University Extension)
- 2023 Plant Hardiness Zone Map: Colorado (USDA Agricultural Research Service)
Checked November 12, 2026. This page is a plain-language summary of Colorado law, not legal advice. Laws change, so check the official sources before you grow.