Would I be be better off doing 3 autos in 5 gallon pots in a 2.5 x 2.5 tent( packed in there) under 450 watt light or would the do better in a 4x4 tent with more space ?
Definitely a 4x4 but I don't know if it's enough light for that area. Someone else will probably tell you. I think it will be but I use hps so I'm not sure
4x4, the extra height alone will be worth it. 450w over a 4x4 area is a bit on the low side, even for high end LED units, but if you aren't chasing yield and you're still just learning, it should be fine.
if your light is the latest and greatest LED style then I would go 4x4. More room is always better bc you can decide how big you want the plants and less risk of not having enough room. Generally you need 30 watts of high quality LED per sq ft so 16 sq ft x 30watts is 480 total watts. Close enough. My 2 centavos.
I'd go 4x4, I've run 2 plants in a 2x2x4(tall) and its tight and tough. Obviously you'll need more space at your place for a 4x4 than a 2x2 but imo the space is worth it. As for lighting when you say 450 Watts, is that the actual power draw, or what the light says it puts out (which means its probably only pulling less than 100 Watts from the wall) I mention this because an actual draw 400+ watt light will generally do you fine in a 4x4. For example I have a couple of SF-4000 lights that actually draw almost 4 amps from the wall, so they are pulling around 440 Watts on a 120V circuit. Here is a 4x8 running two of them (1 per 4x4 section, with some 100W blurples spaced between for supplemental wavelengths) into a healthy flower. However 4x4 is pushing the limits for those lights at the edges, but they can absolutely fry a big healthy plant if put too close. Anyway, each 4x4 bay in the pic has 2 plants in it (plus a little runt squeezed between the bays) thats an 8-10 week veg and another 9-11 week flower for most indica doms. This pic shows two 4x4 bays to give you an idea of what I 4x4 space can hold, 2-3 big girls or maybe 4+ smaller autos depending on how you train, top or screen. I'd go at least 6 feet tall, preferably 7 feet+ if you have the space and can afford it, simply because stretched out photo girls in flower can easily reach 3-4 feet tall as they grow. So you have possibly 3-4 feet of plants, depending your light you'll need likely 1-2 feet of clearance between he canopy and the light, and then another 12-18 inches above the light to allow for heat dissipation and reduce fire risk. Its hard to cram that kind of height into a 4-5 foot tall tent (at least safely imo). Other consideration is larger bar or panel leds can take up a big footprint in your tent ceiling, in a 4x4 you may also need to hang an exhaust and carbon filter on the ceiling if you are trying to be discreet, and that will require clearance between the ceiling and the hot lights if it can't be mounted off to the side. If you care for them well, even cheap vivosun tents can last for years (I have one that been growing perpetually for almost 5 years, so I'd argue if you can, spend a few extra dollars on a bigger tent, so you don't have to do it later if you decide you want to put in more plants, photo plants, bigger lights, etc. I soap out and hose them off and hang them to dry on a clothes line every summer between grows, and once a year put some lube (its like a tube of chapstick for zippers you can get for like $2 off amazon) on the zippers and they just keep coming back for more abuse, so long as you don't bend or snap a pole (but even then most 4x4 poles are standard size so you can order aftermarket parts for most tents, or some generic alternative poles if you snap one) However, if you don't see any future plans to be growing more than a couple of autos for personal use, or you don't have a lot of space for a grow area at your place, a smaller tent might also work. That's my random internet unsolicited advice for the day, hope it helps and best of luck on the grow mate!
sure I got 16sqft of LED(Migrow) light in a 15 sqft room, and if can't get the light right with the dimmer I still got the option to raise the like and inch or so and increase venting weed is one plant that is very very difficult to burn like corn it will take all you got and still love it
without putting words in your mouth re you saying: get a big light or lights bc you can always dim them or move them further away. This way, you can always go to a bigger area to grow in future and you wont have to buy another light. Is this what you are saying/thinking? If so it certainly makes sense. I have a 320 watt LED in a 3x3 and find myself dimming it to 80% most of the grow. Probably would be better if I invested in a PAR meter and adjusted as needed instead of "feeling" what the plants are "telling" me.
last year I hung around here for months, eventually I bought one of shanes light then another 2 arrays each does 4x2ft with eaze, the arrays have so much data on the web its no joke but buddy never buy a par meter just yet they are the price of a light but you can get them as an app for your phone your 320w light could be better in a 4x4ft space than the current 3x3ft check this: https://www.youtube.com/@MIGROLIGHT/videos cheers
Thanks Vee for the info. I guess I intuitively followed your advice. Go big and dial back so you have options. i wont side track more ..sorry op.
With good Samsung LM301B/H diodes. You can get 850-1000PPFD with 400-500W with a decent bar style light in a 4X4. No need for more. It’s useless. I harvested 23oz dried with 385W (860-890PPFD AVG) in my 4X4’ with a ViparSpectra KS-5000 at only 75% power.