Lighting use to force flowering


gooday to all,

i have a question concerning force flowering: when going to the 12/12 regimen, does it matter which light type i use?

i have an Apollo 600 light system which came with an HPS and an MH bulb. would it matter which bulb i used to force? i have been using the HPS bulb during the vegetative stage and wondered if i should use the MH bulb to aid in flowering?

thank you in advance for your help.


I would stick with the hps for flower, mh for veg


You can run with both on at the same time, although controlling the heat can be a challenge. I have a 400W HPS/400W MH lamp and have done both - sometimes just the HPS on, sometime both on. I would say having both on will encourage more growth, perhaps denser but, but it comes at a cost. With the ballast thats around 1000W of usage and I see it in the electric bill big time


thank you both for your help. i go with your advice and hope to see some evidence of flowering soon. roughly how long should it take before some type of flowering begins?


I’ve read that at about a week you should be able to see flowering. But what do I know? My plants are dying currently and I can’t seem to do anything about it.


I use 2050 k 600w hps bulb for flower and 6000k or 6500k mh 600w for veg i run 2 600w lights in a 4x4x6 grow tent. Once you got 2 the 12 hour light cycle it takes 2 weeks to adjust then you start counting the weeks in flower this is what I do have very good results and helps me plan for my next grow. Hope this helps you


oh no, that can certainly be a bad thing–unless it is planned.


so i should count roughly two weeks after starting the 12/12 cycle? not to be ignorant, but what am i counting for? is there a stopping point (weeks) which somewhat dictates when the buds are ready or should i simply watch the colour of the trichomes?


There’s a couple things one is to help to stay on track with your feeding schedule. The next is so you can either top your clones again to keep them going in a smaller tent. Gets you a rough idea of when you should harvest so you can be prepared and have everything ready to go. It’s a way to check your progress to. And yes have a jewellers loupe and pick/harvest by the trichomes. If you plan on doing a preputal grow this helps for planning on transplanting and rotating and when to take clones. Hope this helps you


yes it does and thank you!


24 hours of darkness will kick them into flower… :wink:



really? for how long would i have to do this? one day?


Yep… it’ll jump start the process… 24 hours of darkness and then 12/12 … :wink:



thank you much. will try it tomorrow!


could not do the 24 hour darkness due to the location of plants. however, i had exposed them to 12/12 for 8 days and my girls are decked out in little flowers. yeah daddy!

i’ll send some pictures when the camera battery gets recharged. really excited now and just had to tell someone!


here are photos of my girls:

this is my first grow and roughly half of the crop, so to speak, is shown in the first photo. it seems i was a mite overzealous in my numbers.

couldn’t have done this without y’all. thank you again for all your help.


I’m using reflector 480 from Mars Hydro, and I’m more interested in Mars Pro II recently, but I haven’t used it, so I was wondering if anyone uses Mars Pro II