When to switch to 12/12?

Hey guys. I've been reading all around and haven't seen much about when to switch to 12/12 and start budding. I am currently 40 days into veg and was planning on letting them bud after about 60 days. The larger ones are about 18-21" tall. Do i just let them bud whenever i want and the later i do the more bud i get? Or is there a certain height to switch them over? Heres some pics of course and thanks in advance!

Are you gonna use those t12s to flower them with? I wouldn't let them get much bigger if those are all you're using as they can't have much light penetration, if it's similar to the t5s I use for veg.

They look pretty good though.

The idea is that the bigger you let them get before you flower them the more bud you will get, but you also can't let them get so big that you don't have enough light.

a good rule of thumb to remember is after you switch to 12/12 the plant starts searching for the light and stretches out. you can plan on it doubling or in alot of cases, tripling in size by the time harvest comes. it all depends on how much clearence your grow area has but as pablo said. you must also account for your lighting and how far downward it will penetrate. without light to the lower branches you will not get much bud from them, therefore deminishing returns versus time invested and yeild. i would just flip them shits now but its all up to u brother.

Thanks for the quick reply. I was actually planning on buying a couple of 400 watt HPS lights for budding. So if i do get those bulbs, should i wait a few more weeks?

lildon1 said:

Thanks for the quick reply. I was actually planning on buying a couple of 400 watt HPS lights for budding. So if i do get those bulbs, should i wait a few more weeks?

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100% up to you, but yeah, if you're getting an HPS I'd wait a little while. What kind of space do you plan on covering with 2-400w HPS lights? I'm just curious why you would go for 2-400s is all.

Well I am planning on growing more on my next grow, but I only have 6 plants this grow. The room i have them in is 7'5" x 5'2". Just measured the room haha. You think two 400's is too much? Also, they are perfectly fine to switch now? I thought they were too young or something.

no you can switch at any height. some go 12/12 from seed i flipped mine at 9 inches in a hydro. its all preferance

tanceus is right its all persona preferance. im like him flip at aout 9 inch but i hav 2 rooms where the lights is always on 12/12. but if you want alot of plants flip earlier than if you got a few big plants . Its all about fillingin in your space that you can sufficantly light a min wattage is about 25 watts pr sq ft. but thats my 2cents havea growtastic day

Rule of thumb, you can never have enough light.

lildon1 said:

Well I am planning on growing more on my next grow, but I only have 6 plants this grow. The room i have them in is 7'5" x 5'2". Just measured the room haha. You think two 400's is too much? Also, they are perfectly fine to switch now? I thought they were too young or something.

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No, I don't think that's too much, maybe not enough even, I'm not sure, 7'5x5'2 is a strange area to cover. I'm not sure what i would go with. Probably more light even.

I have 1 600 in a 4x4 and I don't feel like it's enough.

Okay thanks for the help once again. I am going to buy some HPS lights tomorrow and probably switch to 12/12. Thanks for all the advice, wouldn't have made it far without you guys

I have a 5x5 tent running a 1k hps.