When to Plant Cannabis Outdoors: Timing Your Season

Plant cannabis outdoors after your last spring frost, once night temperatures stay reliably above 50 degrees. For most of the United States that falls between mid-April and early June, depending on region. Planting too early risks frost damage and cold stress, while planting on time gives roots warm soil to establish before summer growth.

Why timing matters so much

We run a Colorado nursery, and the most common outdoor mistake we see is planting too early out of excitement. A warm week in April fools growers into transplanting, then a late frost sets plants back or kills them. Cannabis is frost-sensitive, and cold soil stalls root growth even when the air feels fine.

The safe rule is to wait until your last frost date has passed and nights hold above 50 degrees. Warm soil, and not only warm air, is what gets roots moving. Starting with established freshly rooted clones gives you a stronger, faster start once conditions are right than germinating seed outdoors.

Read your region, not the calendar

There is no single national planting date. Your last frost date depends on latitude and altitude, so a grower in Georgia plants weeks before one in Montana. Look up your local last-frost date, then add a week of cushion for safety.

Region	Typical planting window	Notes
Southern US	Late March to April	Long season, watch summer heat
Mid-Atlantic, Midwest	Early to mid May	Wait for stable 50 F nights
Mountain West, high altitude	Late May to June	Late frosts common, harden off well
Pacific Northwest	Mid April to May	Cool, damp; pick mold-resistant strains
Northern US, New England	Late May to early June	Short season, fast-finishing strains

These are starting points, not guarantees. A cold spring pushes everything later. Our guide to cold-climate growing helps if you are on the short-season end.

Harden off before you transplant

Plants started indoors or in a greenhouse are not ready to face full sun and wind on day one. Hardening off means gradually exposing them to outdoor conditions so they toughen up. Skip this and you get sunburned, wind-whipped, stalled plants.

1. Set plants outside in shade for a couple of hours the first day.
2. Add an hour or two of direct sun each day over a week.
3. Leave them out overnight once nights are safely above 50 degrees.
4. Transplant into pre-moistened soil in the cool of morning or evening.

Transplant shock is real, so move plants gently and water them in. Our transplant guide walks through the steps that prevent a stall.

What planting time means for harvest

Photoperiod cannabis does not flower on your schedule; it flowers as fall days shorten, usually starting in late July or August, and finishes September into October. So planting date sets veg length, not harvest date. Plant on time and you get months of veg for a big plant. Plant late and you get a smaller plant that still flowers on the same fall clock.

This is why early planting builds size while late planting caps it. If you want a rough map of the whole outdoor season, our indoor vs outdoor guide covers the arc from transplant to harvest.

Every technique here works better with strong genetics. Browse our rooted, HLVd-tested clones or start with forgiving beginner strains.

Frequently asked questions

What month should I plant cannabis outdoors?

Most growers plant between mid-April and early June, after the last spring frost. Southern states can plant in late March or April; northern and high-altitude regions wait until late May or June. The rule that matters more than the month is stable night temperatures above 50 degrees and no more frost risk.

Can I plant cannabis too early?

Yes, and it is the most common outdoor mistake. Planting before the last frost risks cold damage or death, and cold soil stalls root growth even when the air feels warm. A warm April week tempts many growers, but a late frost can undo it. Wait for stable 50-degree nights before transplanting.

Does planting date change when cannabis flowers?

No. Photoperiod cannabis flowers as fall days shorten, regardless of when you planted, usually starting in late July or August. Planting date sets how long the plant vegetates and how big it gets, not when it flowers. Plant earlier for a larger plant; plant late and it still flowers on the same fall schedule.

Should I harden off clones before planting?

Yes. Plants raised indoors or in a greenhouse need a week of gradual outdoor exposure to avoid sunburn and wind stress. Start with a couple of shaded hours, add sun daily, and transplant once nights stay above 50 degrees. Skipping this step stalls plants and can undo weeks of early growth.

Ready when your window opens? Order freshly rooted clones timed to your last-frost date and hit the ground running.