# How many plants under a 600 Watt HPS?

Discussion in 'First Time Marijuana Growers' started by imageek, Apr 29, 2016.

1. New to this, but trying to figure out how many plans can be grown under a 600 watt light.

I've read that HPS lights give off around 100 lumens per watt, and that ideally 7000 lumens are required per square foot. Estimating that each plant occupies 1 square foot the calculation would be:

Total lumens: 600 x 100 = 60,000
Lumens per plant: 7000

60,000 / 7000 = 8.5

So give or take you can do about 8 plants right? But, I am thinking that the plants on the outer edge of the light won't be get half as much light and won't yield as much. Plus, I'd imagine a lot of light is wasted by reaching the lower parts of the plant that don't yield many buds (is this the reason for SOG?).

Am I off base here and anything I've missed?

I'd be interested in reading anything academic related to this. I'm sure this is a subject related to botony.

2. a 600 watt HPS Is good for 4 plants up to 7' tall.

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3. That was my plan to do 4 too Was just wondering about the theory side of it.

4.
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5. I do anywhere from 3-4 large plants up to 15 small packed plants in a SoG under my 600.

I tend to prefer doing a few big ones over a lot of smaller ones.

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6. It's the area, you need about 2 square feet per plant so a 600 watt covers a 4x4 with is 4 2 foot squares.

7. How's the yield difference in the space between 3 or 4 big ones and 15 little sog'd? I've never tried sog.

8. when I do the 3-4 big plants I usually get 4-8 oz per plant depending on the exact size and strain, and the 15 plants I get like 14-28g per plant again depending on size and strain (usually I would just flower them after the clones are rooted).

they tend to give similar yields but the big plants yield higher more consistently. The sea of green is good if you want a lot of big fat buds but less of them.

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9. Impressive man!

10. Hi i get a 4*4*6tent and flower 4 maximum . I got 4 under 600hps at min but in late veg at min and been lst and fimmed . Any more than 4 is too much.. if another tent comes free in next week or so i will move one to make only three in this size tent. Good luck. Less is more ... xxx

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11. I have tried growing big plants, little plants, and everything in-between over the decades. And what I go by now is space rather than the light. The light should already match the space coverage wise. My best grow space was a tent I built myself using poly-panda film and 2'x4''s. The overall tent was 10'x'6' with 6'x6' for the bloom side and the remaining 4'x6' for the veg side. The veg side had 1,000 watts of MH and the bloom side had 2,000 watts for the 6'x6' space. Yes, I got tremendous yields but even then 9 plants in the bloom side was pushing it.

With the current 4.5'x4.5' tent I have, I stop at 4 plants. Any more than that and the plants just grow into each other blocking ventilation and giving haven to mites, mildew, etc. This last crop I put two plants in the room and that filled it. They were year old mother plants that had gotten too big for my veg room.

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12. The last 2 grows I have scrogged with 4 plants. Prior to that I did a dozen or so grows with 6 plants under a 600 in a 4x6.
Avg. 20 zips either way.
Here is one of my last 6 plant grows...
The Stretch

13. i have a 6.5 x 4.5 area that i started out using 2 x 600w hps with 12 plants. that is the max (100w per plant) but i ended up adding another 400w hps in between the 2 x 600hps. now i can grow the 12 plants much better with an improved yield. if i was just using one 600 now, i would just do 4 or 5 plants max. if i had 2 x 600hps, i would do 9. (3 rows of 3)

14. i yield on average 2.5 to 3lb under the 3 hps lights & 12 plants.

15. #15
Last edited: Dec 31, 2018
Do you have a pic of that?
Edit: I only ask because my 4x6 is pretty packed when it produces a bit over an lb.

16. I know this is someone else’s forum but dayyyyyuuum that’s nice bruv !
I plan on doin similar once I can financially

17. i am about a week away from harvest, i will take some pics wen i start trimming. last crop i had 12 plants, this time i ended up with 14 by accident. most of my plants avg rite around 3+ ozs but last cycle i had 4 plants that was over 1/4lb. when i was doing cuttings, my avg yield was about half of that. i doubled my yield by growing only seed plants. it does take a little longer but i just prefer starting from seeds.

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18. this is a pic of 2 grows ago about 6 weeks into flower. yield was 2.5lb trimmed & dried. 5 weeks veg and 9 weeks flower. fox farms soil and nutes. filtered water with calmagic added. 12 x 3 gallon pots with temps in the 70s. 2 x 600hps & 1 x 400hps.

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19. I flower in a 5x5 tent with a 4.5x4.5 foot scrog screen. I use a dual bulb Raptor with two 600s plant count varies but yeld all said and done 1.50-1.75 pounds average.

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