Too tall!! 2 weeks into 12/12. Can i top them??

Hi, Pretty much says it above.

I'm growing 5 plants under a 250watt hps. Started them under a flouresant for 2 weeks. Then vegged for 4 weeks under HPS. 2 weeks into 12/12 and they are about 150cm tall. I can only raise my light another 30cm ish. I know they are stretching, but my first grow was hugely successful. They didn't get above 1m. Anyway my question is this, as they are only just displaying pistils can i top them? Or now they are starting to flower will they stop growing in height?

Also they are supposed to have a flowering period of 6weeks. Is this from when i switched the light or when they start to flower?

Thanks as always

I wouldnt do any pruning once I switch to 12/12. Adds alot of time to flowering.

A 6 week strain? Not sure about that unless its LowRider.

In most cases the weeks given for a strain's flowering time is usually counted after plants have shown sex.

An 8 week strain....8weeks after the plants have been under 12/12 for about 2 weeks. Which makes it about 10 weeks from 12/12 with an 8 week strain on avg.

Some strains finish a bit earlier.....Some will take longer.

Sorry meant 8 week. I'm goring Power Plant.

There is a growth spurt that last a couple of weeks into flower but it should stop soon and just concentrate on flower growth. if you have another 30cm to raise i think it should be o.k.

if you are worried, maybe you can LST the plants at an angle to keep them lower. worked for me. see my grow journal.