How many plants can i fit under a 400w MH and HPS

chronichaze09

Active Member
I started iff with CFLs but i hear you get way better yield using better lights. can someone tell me how man plants i can grow under a 400W light and get the most yield??
 

shamegame

Well-Known Member
I have found that 4 plants during flower is about the max for a 400w unless they are tiny plants.
 

yotone

Well-Known Member
I have found that 4 plants during flower is about the max for a 400w unless they are tiny plants.
I believe thats also correct.
on my first real grow attempt i planted 15 seeds and with trial and errors i now have 3 females that are on their 4 week of flowering and im already looking at a little bit of crowding problems.
 

thumper925

Well-Known Member
i have 10 under my 400 watt but im also going to add 8 more plants and one more 400 watter but i just started this setup so no results to give u on it
 

david6767

Well-Known Member
i have 10 under my 400 watt but im also going to add 8 more plants and one more 400 watter but i just started this setup so no results to give u on it
it depends on the size and strain of the plants, and whether you are flowering or vegging.

I have 20 plants under my 400W light in a SOG grow.

Obviously, when the plants are sexed and the males removed there will be enough room to flower the others.

Also depends on whether you have the opportunity to effectively double your light canopy by employing a light rail.
 

Corso312

Well-Known Member
hey cool ... now i ordered a 400 watt tonight mh/hps switchable ...what yeild can i expect if i want max yeild do u think 1 lb every 3 months is realistic?
 

shamegame

Well-Known Member
your wasting light. 4?????????
I suppose it would depend on your hood type and floorspace. But I have a 400w and I can tell you that I have vegged up to 12 plants with it up to 1 ft or a little less, but in flower I have found that unless I were to lollipop them or something, that 4 plants seems to be the max number of 3 footers that I can put in there without some of the plants not getting full light. These 4 plants take up a footprint of about 2.5 x 2.5 feet which is about the max for a 400w no?
 

capncash

Well-Known Member
it all depends on how big you are going to veg them. It better be 4 big ass plants. You could do 25 small plants or 1 big plant and come up with the same amount. You will likely get about 200g per harvest. 1/2g per watt.
 

thedoctorzoidberg

Well-Known Member
I suppose it would depend on your hood type and floorspace. But I have a 400w and I can tell you that I have vegged up to 12 plants with it up to 1 ft or a little less, but in flower I have found that unless I were to lollipop them or something, that 4 plants seems to be the max number of 3 footers that I can put in there without some of the plants not getting full light. These 4 plants take up a footprint of about 2.5 x 2.5 feet which is about the max for a 400w no?
hood and distance is most important..... and i believe a 400 watter is good for 4 x 4 if used properly.
 

mygirls

Medical Marijuana (MOD)
hood and distance is most important..... and i believe a 400 watter is good for 4 x 4 if used properly.
distance aint the prob. heat, just blow the heat away. SEE EVERYTHING IS FINE 1000WTT HPS no hood vent see were they R. NO BURNED BUDS A HEAD OF TIME.
 

thedoctorzoidberg

Well-Known Member
distance aint the prob. heat, just blow the heat away. SEE EVERYTHING IS FINE 1000WTT HPS no hood vent see were they R. NO BURNED BUDS A HEAD OF TIME.
i wasen't saying it needs to be FAR away... i keep mine as close as possible.... i was saying distance in reference to lumen output..... the further away the less lumens.....

you are a genius, that plant is awesome.
 

shamegame

Well-Known Member
From what I understand, the useable footprints for HIDs are something to the effect of:

400w- 3x3ft MAX ( 2x2ft = optimal )
600w- 4x4ft MAX ( 3x3ft = optimal )
1000w- 6x6ft MAX ( 5x5ft = optimal )

You can put as many plants as you want in this space depending on their size.
 

thedoctorzoidberg

Well-Known Member
From what I understand, the useable footprints for HIDs are something to the effect of:

400w- 3x3ft MAX ( 2x2ft = optimal )
600w- 4x4ft MAX ( 3x3ft = optimal )
100w- 6x6ft MAX ( 5x5ft = optimal )

You can put as many plants as you want in this space depending on their size.
i can read a book on how to grow tomatoes.... but cherry tomatoes and jumbo tomates are quite differen't...... guidelines are guidelines... and those are good for what they are.... i do not follow that chart, although i can agree that it is a good reference.
 

UserFriendly

New Member
one 400w over a square meter with each plant using 16 square inches = 81-100 plants. Theres no reason for you not to harvest a pound every two months.
 

shamegame

Well-Known Member
one 400w over a square meter with each plant using 16 square inches = 81-100 plants. Theres no reason for you not to harvest a pound every two months.
4"x4" per plant? that seems awful crowded unless you are talking tiny little plants. Also, you need to take in plant limits and laws- getting caught with 80-100 plants will get you 5-10.
 
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