After Summer Solstice on the 21 December the days start getting shorter. Planting a photoperiod then is perfect if you want to keep it contained. The plant will vegetate for 4-6 weeks and start flowering as it would when the light cycle changes indoors. The sun is getting shorter by 55 seconds each day. I prefer to plant Auto seeds in September when the days are getting longer. This allows the auto to grow its full vegetation allowable within the genetics. Harvest in December. Plant photoperiod in December harvest end March or April. An auto planted after 21 December won’t reach full potential because the light is fading already. It will flower almost instantly after germination. Make use of the moon cycles planting the week leading up to full moon. I’ve seen noticeable improvement in germination and growth. And time your grows to match the spring and summer solstice. Use the Suns schedule for lengthening days and shortening days to your advantage. 20% cow Manure, a cup of bone Meal, worm castings, half cup Epsom salts and some Lime mixed into your potting soil should carry your plants beautifully into flowering. When flowering starts water with comfrey Tea rich in potassium and calcium.
Most autos are rubbish.
Try growing Royal Gorilla Auto from RQS or White Widow auto from Crop King Seeds.