Outdoor Cannabis Planting Calendar by Zip Code

Zones 6 through 9 give outdoor cannabis growers the most flexibility. Zone 7 is often considered the sweet spot: the season is long enough for full season photoperiods to finish comfortably, the fall is warm enough to avoid early frost problems, and all three variety types have viable outdoor windows. Zones 5 and below work well for autoflowers and short season varieties but may cut full season plants short.

After your last frost date and once nighttime temperatures are reliably above 50°F. For most of the US that means late April to mid-May. Use the zip code tool above to get specific dates for your location. The tool also considers day length, which matters for photoperiod varieties. Planting too early when days are still short can cause photoperiod plants to flower prematurely before they have built any size.

Both are photoperiod varieties that flower based on day length, not age. The difference is the day length threshold that triggers flowering. Full season strains wait until days drop to roughly 13 hours before flowering, which happens in late summer or early fall. Short season strains begin flowering when days are still closer to 14 hours, earlier in the summer, which means they finish earlier and work better in northern zones or for growers who want an earlier harvest.

Autoflowers can be grown in any zone that has at least 10 consecutive frost-free weeks. Because they do not respond to day length, they are not constrained by the photoperiod growing season. They just need warm temperatures and enough time to complete their cycle. In Zones 3 and 4 the frost-free window can be tight, sometimes under 90 days, but a well-timed run started right after last frost will usually finish before fall frost arrives.

Young seedlings and plants in early vegetative growth are very frost-sensitive and can be killed by temperatures near 32°F. Mature plants in late flower are more tolerant. A light frost in the 28 to 32°F range for a few hours typically will not ruin a harvest, though it will add stress and slow resin production. Hard, sustained freezes will damage buds. If frost is forecast and your plants are not ready, covering them overnight with fabric row covers buys a few more days without significant harm.

Enter your zip code in the tool at the top of this page. It returns your zone, estimated frost dates, and outdoor planting windows for each cannabis variety type, all based on the actual daylight hours for your location. You can also look up your zone directly on the USDA Plant Hardiness Zone Map.

All seeds sold by Triangle Seeds are legal to purchase and ship anywhere in the US. What varies by state is whether you can legally germinate and grow them. Home cultivation laws differ significantly across the country, from states with no restrictions to states where growing at home is still prohibited. See our state home grow guides for a breakdown of what is legal where you live, including plant limits, security requirements, and possession rules.