Durring 18 hour cycle.
Here is what I do. I take a brown paper bag and lightly tie it around one end of a branch so it gets only a 12 hour cycle. I repeat this every day for about a week or two. If it buds great, if it is a male I remove it.
Why would you keep a male plant? If you don't want to hassle with buying seeds all the time you should keep a mother plant around for your clones.
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This next part is from one of my other posts. Was to lazy to type it again.
I have Colombian Gold, Panama red, Michoacan, and Oaxacan Red mothers I have kept since 1974. So not all is lost for some of us. To bad I don't have males of these (except Coloumbian Gold-- just a few seeds left), because I would move to Canada and sell seed of these rare strains. I have passed on a few clones over the years to friends and they still try hard to keep mothers of these strains (lol). See also my next generation of bud, I think you'll like -->
Numb Nutz #1 x White Widow!
Almost forgot to mention--> Over the years I took all the seed from all my rare stuff (Colombian Gold, Panama red, Michoacan, Oaxacan Red, Acapulco Gold, Thai Stick, Maui, Hawaiin, Maui Wowee, and on and on and on (to many to list) and put them in a plastic container which has been sealed for a very long time. Any way I took some out and placed in wet paper towel to seed, out of 20 seeds 1 poped up, just not sure what kind it is or if it's a male. I'm hoping for female (lol). Here soon I'll start a pic gallery of this plant to show the world! I'll keep trying to seed these seeds in an attempt to get a male and female of one of these rare strains, so wish me the best of luck!
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Hard to keep mothers for years if they are in rockwool or hydro system. I use soil for them if I plan on keeping for years to come. I carefully replace as much soil as possible at least once a year. Not an easy thing to do, and a good way to lose my plants. Just the way I feel about soil.