This subcategory is for autoflowering cannabis varieties, or “autos” for short (how autoflowers work). An autoflower starts to flower once the plant is old enough. Day length does not trigger it. Most other cannabis is “photoperiod” cannabis, which only flowers when the nights get long enough.
What Belongs Here
- Autoflower grow diaries and results. A grow diary is a record of one run from seed to harvest, with dates, settings and photos.
- Strain recommendations and comparisons
- Optimal light schedules (18/6, 20/4, 24/0 debates). The numbers are hours of light and hours of darkness per day. For example, 18/6 means 18 hours on and 6 hours off, and 24/0 means the lights never go off. Autos don’t need darkness to flower, so growers disagree about how many hours of light are worth the electricity.
- Training techniques suitable for autos. These include LST (low-stress training: bending and tying stems so the plant grows wide instead of tall) and the timing of topping (cutting off the main growing tip so the plant splits into two main shoots). Timing matters because an auto has a short, fixed amount of time to recover from any cut.
- Nutrient schedules adapted for autoflowers
- Autoflower breeding and development
- Indoor vs. outdoor autoflower growing
Translator’s note: Thai and Southeast Asian conditions change some of the advice you will read in guides written for cooler countries.
- Outdoors in the rainy season: Humid air settles in dense buds and raises the risk of bud rot. An auto finishes in a short, predictable time, so you can plan harvest for a drier stretch. Post your sowing and harvest dates so growers in your area can see which windows worked.
- Heat of 30–35 °C: Lamps add heat to a closed room, and long light schedules add more. Check the temperature at the top of the plants during the hottest part of the day. That reading tells you whether you need more airflow or fewer light hours. Many growers in hot climates put the dark hours in the hottest part of the day.
- Power cuts on 24/0: A power cut will not change when an auto flowers, because flowering depends on age. A long cut still means lost light hours, and fans or air-conditioning stop working while the room heats up. Write down every cut and how long it lasted in your diary, so you can link any stress you see to its cause.
Guidelines
All content must comply with the Notification of the Thai Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568 (2025) and the Ministerial Regulations of B.E. 2569 (2026).
Translator’s note: Here is what these rules mean for posts in this subcategory.
- The 2025 notification: Cannabis flower is a controlled herb under the Thai Traditional Medicine Protection Act B.E. 2542 (1999), and this has applied since 26 June 2025. Flower may be sold only with a PT 33 (ภ.ท.33) prescription, for a maximum of 30 days. Advertising flower and selling it online are prohibited. So do not offer, price or advertise flower here.
- The two 2026 regulations: The Ministerial Regulation on Cannabis or Hemp Extracts has applied since 26 April 2026. The Ministerial Regulation on Controlled Herbs (No. 2) has applied since 30 April 2026 and tightens the licence criteria for cannabis flower. For a plain-language summary, see Thailand’s two Ministerial Regulations of 2026.
Where to Start
- Post a grow diary of your auto run. Include the strain and breeder, sowing date, light schedule, pot size and growing medium, the highest temperature and humidity, harvest day and dry yield. With the same details from many growers, everyone can compare autos under Thai and Southeast Asian conditions.
- Ask your question below this topic, or open a new topic with photos and your light schedule.