Outdoor Cannabis Planting Calendar by Zip Code
Enter your zip code to get outdoor planting windows for your location, including whether full season or short season strain types will have enough season to finish before your first frost.
These recommendations are for outdoor growing only. If you're growing indoors or in a greenhouse with supplemental lighting, you can grow any variety regardless of your location or time of year.
Your exact planting, flowering, and harvest dates, calculated from your latitude.
Outdoor Cannabis Growing Season by State
Pick your state to see its hardiness zone range, how long the outdoor season runs, and which variety types have time to finish there. For dates specific to your exact location, use the zip code tool above.
How Daylight Hours Control Your Outdoor Season
Cannabis does not decide when to flower based on the calendar. It decides based on light, or on age, depending on which type you plant. That single difference drives every date the tool gives you.
Stays in vegetative growth through the long days of summer, putting on size and branching. Once daylight drops past the threshold, it reads that as fall arriving and flips to flower.
What this means for you: your season is the gap between last frost and that flip. In northern zones it is tight. In southern zones there is room for bigger plants and a slower schedule.
Ignores day length completely. It flowers on its own clock and finishes in roughly 10 weeks from seed no matter how much light it gets.
What this means for you: you only need a frost-free window long enough to finish. That makes autoflowers the safest option for a short or unpredictable season.
How to Read Your Results
Each result card gives you three things. Here is what the phrases mean.
- "Transplant outdoors between"Your planting windowOut too early and short days can trigger premature flowering, which costs you weeks. Out too late and the plant never builds enough size before flowering starts.
- "Begin flowering around"Calculated from your latitudeThe date your daylight drops past the flowering threshold. Roughly 13 hours for full season, 14 for short season. Autoflowers have no such date.
- "Harvest around"Flowering plus 9 weeksMost varieties flower for 8 to 10 weeks. Check your strain's listed time and shift the date from there.
Frequently Asked Questions
What USDA zone is best for growing cannabis outdoors?
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.
When should I plant cannabis outdoors?
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.
What is the difference between full season and short season cannabis?
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.
Can autoflowers be grown in any USDA zone?
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.
What happens if my plants are still outside when frost hits?
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.
How do I find my hardiness zone by zip code?
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.
Are cannabis seeds legal to buy in my state?
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.
