Ok Blade, you can keep photo regular plants in veg as long as you like. Simply leave the light cycle at 18/6.
When your plant is sexually mature you will see, calyx’s normally in pairs at the branch unions like this
Once you introduce longer dark periods of 12 hours, a couple weeks later you will notice these hairs begin to stack up more quickly and ultimately form a button
Like this
These buttons grow together after a few weeks to create a cola
Like this
Then after a few more weeks the calyx production slows or stops altogether and the hairs become red or brownish like this
Its important to note that bud swelling requires that the grower allows these calyxes to die because the bracts they attatch to is not only where the majority of the trichomes are but wont swell until the calyx’s are dead! When you harvest with live calyx you can rest assured you are losing significant bud mass and resin production. Hope this helps and enjoy your growing!