Hi all iv had my plants in 18/6 for one week now, when can i put them into flowering as I only have ten week left till the tent has to come down when i move house, below is a pic of one of them and the range from 45mm to 60mm tall
You can start 12/12 any time.Some people start 12/12 right from the start ,but plants become smaller with small amount of goods at the end. On average people switch to 12/12 when plant is about 12" high (~ 4-5 weeks of 18/6) mostly because they have limited head room (By the end of the first month of 12/12 plant can triple in size and then stops to grow up). You can do simple calculation to get proximate height of your plant before switching to 12/12. (TOTAL HEAD ROOM)-(HEIGHT OF THE POT)-(HEIGHT OF THE REFLECTOR)-(SAFE DISTANCE BETWEEN YOUR PLANTS AND REFLECTOR) =X (X-is how much room you have left) , X:3=y , y-Final; height by the end of 18/6..... I hope you got the idea.
Be careful, this is what ruined my first grow. I Swiched to 12/12 About a week too late, by the second week into flower it had outgrown all the space I had, then grew into the lights, after about 4 days I made the decision too pull it out and start over, this time flowering much earlier
There is actual chemicals available to stop plants from growing up in case if you feel that you are running out of the head room. Also super cropping can be done to stop the plants from growing up.
Well I was out of room horizontally too so all together I was kinda fucked, this time I am growing a mostly sativa strain so I am hopeing it will stay right in the parameters of my 2 foot wide by 4 foot tall grow box