The right time to plant autoflowers outside is after your last frost, once nights stay above about 50 degrees Fahrenheit and the soil has warmed. Because autoflower seeds flower by age rather than day length, you can also plant several crops through the season, as long as each one finishes before cold, wet weather returns. In much of the United States the main window runs from late April to early July, but it shifts by region. This guide breaks it down. It is for adults 21 and older where outdoor home growing is legal.

Why autoflowers are flexible outdoors

Photoperiod plants wait for shorter days to flower, so in most of the US they finish in fall. Autoflowers ignore day length and finish roughly 9 to 12 weeks after sprouting. That means:

• You can harvest in midsummer, before late season mold and frost.
• You can plant two or even three crops in a long season.
• You can plant later in spring if the weather is slow to warm.

The catch is that autoflowers do best with long, sunny days. Planting too early or too late in the season means fewer hours of light and smaller plants.

The basic rules for any region

1. Wait for frost to pass. Check your local average last frost date from your state extension service or the National Weather Service.
2. Watch the nights. Cold nights below about 50 degrees slow young autoflowers.
3. Warm the soil. Seedlings grow slowly in cold soil. See our guide to soil temperature for planting cannabis.
4. Finish before trouble. Count back 9 to 12 weeks from the start of your rainy season, monsoon or first fall frost.

Planting windows by region

These are typical ranges, not promises. Local weather can shift them by weeks.

Pacific Northwest

Plant from mid May to June. Aim to harvest before the fall rains, which often begin in late September or October. Choose mold resistant autoflowers and avoid planting a crop that will finish in wet weather.

California and the Southwest

Coastal and inland California can plant from April through July in many areas. In the hot desert Southwest, spring crops planted in March or April can finish before peak summer heat, and a second crop can go in after the hottest weeks. Watch for the summer monsoon in Arizona and New Mexico, covered in our post on monsoon season outdoor cannabis.

Rocky Mountains

High elevation means late frosts and early falls. Plant in late May or early June and choose fast, compact autoflowers. Protect plants from hail and strong sun.

Midwest and Great Lakes

Plant from mid May to early June after frost risk passes. A second crop can go in by late June to finish in September. Watch humidity in August.

Northeast

Plant from late May to mid June. Harvest by mid September in northern areas to beat cold, wet nights.

Southeast and Gulf Coast

Warm weather arrives early, so planting can start in March or April. The challenge is humidity and hurricane season. Plant early crops to finish before the peak of late summer storms and choose mold resistant genetics.

Texas and the southern Plains

Spring crops can go in from March to April and finish before the hottest weeks. Fall crops planted in late summer can work in milder areas. Check your state law carefully, as home growing is not legal everywhere.

How to run two or three crops

Start the first crop as soon as nights are warm. Start the second about four to six weeks later, either outdoors or indoors under light so it is ready to plant out as the first one flowers. In long seasons, a third crop planted by early July can finish in late September. Space crops so each gets full sun.

Starting indoors and moving out

Germinate seeds indoors and grow them under light for one to two weeks before moving them outside. Harden seedlings off over several days by giving them a little more outdoor time each day. Move them once only, into their final container or bed, as transplanting an autoflower costs growing time.

Site and container tips

• Full sun. Eight hours or more of direct light.
• Fabric pots. Easy to move during storms or frost.
• Good drainage. Autoflowers dislike wet roots.
• Privacy. Many states require plants to be locked and out of public view.

A sample two crop calendar

Here is how a simple two crop season might look in a mild, temperate area. Adjust it to your frost dates.

• Early May: germinate crop one indoors under light.
• Mid May: harden off and plant crop one outside after frost risk passes.
• Mid June: germinate crop two indoors.
• Late June: plant crop two outside.
• Late July to early August: harvest crop one.
• September: harvest crop two before cool, wet nights arrive.

Keep a simple log of planting dates and harvest dates each year. After one or two seasons you will know exactly how your local weather treats autoflowers.

Grow legally and responsibly

Home cultivation is only legal in some states, and each state sets its own plant limits, locking rules and rules about whether plants can be visible from a public place. You must be 21 or older to buy seeds from Kind Seed Co, and you should grow only where your state and city allow it. Check your state rules in our guide to the legal requirements for growing weed plants in your state before you plant. Federal treatment of cannabis seeds is also changing, so read our December 11 2026 seed rule explainer before you order. Keep plants and harvested flower locked away from children, pets and visitors, and never drive after using cannabis. This article is general information about gardening. It is not legal advice and it is not medical advice.

Frequently asked questions

When is the best time to plant autoflowers outdoors?

After your last frost, when nights stay above about 50 degrees and the soil is warm. In much of the US that falls between late April and early June.

Can I plant autoflowers outside in July?

In many regions, yes, if the plant can finish in 9 to 12 weeks before fall rain or frost. Count back from your expected first frost.

How many autoflower crops can I grow outside in a year?

Two is common in most regions. Long, warm seasons may allow three.

Should I start autoflowers indoors first?

Starting indoors for one to two weeks protects seedlings from cold and pests. Move them only once into the final container.

Do autoflowers need long days outside?

They flower on their own schedule, but longer, sunnier days help them grow bigger. That is why midsummer crops usually do best.

Ready to start

Browse the full range in the Kind Seed Co shop or go straight to autoflower seeds. Kind Seed Co sells only to adults 21 and older. Always follow the home grow laws where you live.