The plants are now strong enough and tall enough to be able to clip the top to produce multiple colas. My first topping, (I only top twice), is on day 30 of the grow. I clip the plants just above their 4th or 5th node. Some of the tips are so tiny that I have to use a magnifying glass to pin point the exact spot of the cut. It will take few days for them to recover, but they do pretty well. On day 32, the temperatures outside have finally reached above 20ºC (68F), so I can start hardening them off for later outdoor replanting. They are first spending few hours a day in shade, before introducing full sun to them. Last year we learned the hard way when we burned all our plants initially and had to wait for them to recover. Day 34 - plants are put in full sun for about an hour and half. No sunburn or leaf yellowing. I have eased off on nutes a bit, to let them recover from topping and hardening and give them only water for few days. Day 35 - weather has turned bad and cold, so back inside we are under the lamps. We have had to raise the lights by 7" now to accommodate for the new growth. They are getting taller with each day.