MH or HPS for autoflowers?

Hi guys,
This is my first time posting on the site but I have read a bunch of it over the past year. This will be my first batch of autoflowers. I bought the seeds from ilgm and I can’t find anything on whether to use metal halides or high pressure sodium or change them out during the phases like a photo period? I have a little experience growing photoperiods but this being my first Autoflower grow any tips should be helpful. Thanks

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I would run the mh till pre flower then switch to hps. U can u hps thru out but mh has the blue for better veg


I agree with @Liljoe but I would run the mh until stretch is almost over. Unless you are looking for longer node spacing. Mh has more blue which is better for vegg. During the stretch, that’s still vegg. Hps has more red, which is better for flower


Good call on switching after stretch @HornHead I didnt think of that because I run both mh and hps from start to finish, best of both lights thru out :wink:


Thanks guys I was thinking it wouldn’t be any different from the photoperiods but figured I would still all just to know… Are 3 gallon pots big enough for autos?

I use 7 gallons and get big plants. What autos and from where?

I grow photos, also using 7 gal pots

White widow and blueberry autos from ILGM. I only use 4 gallon pots for my photos but with my 2 -1000 watt hid lights only being a tad over 6’ high in my tent I do a screen of green around the 4’ mark, but again those are photos.

Don’t think you can scrog autos but I grow wwa a lot and top everyone. I tie the branches to the sides of pot so it resembles a candelabra underneath. I end up with a nice flat canopy


I like it. Guess maybe because with photos you veg to the size you want but what these Autos they have a lifecycle so I’m trying to get more idea of their true size, of course if you spread out the branches and all that you can almost make em the size you want but if you had a 5 by 9 tent with two 1000 watt Lights how many would you be thinking in there max yeild results? I don’t have CO2 in the tent but pretty much have complete control of everything else heat,humidity, air flow, etc

Technically you could run either of those bulbs from start to finish. Plant responses are just a little different under different wavelengths of light. The light emitted by mh will promote more compact growth and the light emitted by hps better flower production. That’s why you see a lot of people switch. Seed to harvest grows under hps aren’t all that uncommon though. Just puts out a little longer node spacing as pointed out by @HornHead I believe. Not ideal if you are height limited and letting plants grow naturally. But vegging under hps can be great for filling a scrog. Although I would also agree not ideal with auto flowering plants to scrog.

Yea thanks. I do understand the differences as I’ve always swapped out bulbs for veg/ flower with my photo plants. I’ve just never grown autos and wasnt sure if there was any other traits as far as lighting other than not having to change the time schedule for Autos. And mature size of white widow and blueberry autos

Those look awesome! I know you said you always top your white widows, but how many times a piece?

Just once at the fourth node. I follow this guideline is that has five nodes by the end of the second week of its life go ahead cuz that’s growing good and healthy

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And in you final picture there(looks like just before you harvested) do you have a estimated height? And was that a soil grow? Sorry about the 20 questions and I know everybody’s results vary just brand new to autos so trying to soak the info I can and you’ve grown the ww and seemed to do well.

If I didn’t tie it down, 5’ no shittin’ I grow outside too, and topped a plant that I had planned on growing inside, ran outta room and dug a whole in the field, that topped plant ended up growing about 5 foot tall. And I’ve had one that I let grow naturally, it only grew to about 3’

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Ya that good to know since everything I read was around 3ft with no topping. Do the respond the same as photos when HST’ed or supercropped?

I try to avoid high stress. You can lst the shit outta them no problem, at least I haven’t had any. I’ll supercrop when stretching is over

It’s almost as if your saying that a topped auto will grow a lot taller then a nontopped? I’ve also thought about putting just a few outside here in Michigan. its either a great or bad end result. I haven’t found the middle ground for outdoor mid MI. The seasons here like to be crazy.

I’m right under you in mid Ohio. I’ll start autos inside for about 2 weeks then plant them outside in the corn fields with minimal supervision and they grow fine