simple question simple answers

[HappelWood]

i could figure out at what height a 400w light would be beating down 75w/sqaure foot because light DOES diminish at roughly 50% a foot. The sun is so powerful, this variable never plays a factor, which is why it's kinda good to grow outside.

Now, if we take 50000lumens/400w=125lumens/watt, 125 lumens x 75w (cause i'm saying use 75w a square foot), is 9375 lumens/square foot, which is actually above your number. I think 75w a square foot is unrealistic for a full garden, i want 66w a square foot or in a 2x2, that would be 8250lumens per square foot. This makes sense to me unless i'm missing a fundamental concept here. Lumens are the most important number, not watts. a 400w can produce even 550000 lumens which will change the lumens per wat per square foot.

These are rough numbers to figure out roughly where you light should be.

 

[himzluvhishallie]

so ummm my plants will b fine n 86 degrees??

 

[HappelWood]

actualy, 56w/square foot, 7125 lumes per sqare foot, 250w light, 2x2 grow space. Which means i would want the light about 2feet above the top of my plants, a little more really. I think that 66 number is me remembering something wrong.

 

[HappelWood]

I would not run at 86 degrees. Raise your light or add fans. You want fans that concentrate airflow, like CPU fans.

 

[himzluvhishallie]

ok well thanx...i guess ill raise em a lil bit

 

[markman12]

another question...what is a nute??

 

[HappelWood]

nutrients, fertilizer

 

[markman12]

ohh all right thanks..now what do i use for nutrients durin flower

 

[tusseltussel]

https://www.rollitup.org/general-marijuana-growing/723-things-know-about-lighting.html

 

[HappelWood]

that doesn't change anything i've said. His formula for lumens per square foot doesn' factor in how far the light is from the plant. It diminishes the farther from the light you get (that just makes sense. And 50% a foot is the number i've read, and the number i'm doing math with). I would need to do so calc to create an actual forumal that factors in all the variables.

No one has the light on the plants unless they are growing LED, and even then, wtf. So his formula for lumens per square foot isn't useful. And if you did have the light right on the plant, it wouldn't light up enough area, especially if i was using a 400w i would want a 3x3 grow space.

I just think 86 degrees is too warm, and it's only going to get worse because plant grow up towards light which will make them closer to the light, making it hotter. You can wait until the plants start showing heat stress and then move it up, or you can create a wall and raise the light everytime it hits that wall. I prefer just using my hand, but my hand agrees with about 86 degrees from experience. People with CO2 can have their shit be as high as 95 degrees (max) and the plants be ok.

 

[markman12]

i just realized i am using a halogen light..ive read this is a bad idea..and im worried im gonna burn my house down..is a 40 watt cfl light better than a halogen light

 

[tusseltussel]

i just realized i am using a halogen light..ive read this is a bad idea..and im worried im gonna burn my house down..is a 40 watt cfl light better than a halogen light

halogen=no no

 

[markman12]

haha yea why tho

 

[himzluvhishallie]

jus dont..

 

[markman12]

ok so i dont have money for the MH bulbs..but can i get like 4 40 watt CFL

 

[himzluvhishallie]

yes do that...ALOT BETTER...

 

[markman12]

2-Pack 60-Watt Equivalent CFL Bulbs how bout like 4 of these..in ur opinion r these good..i dont have much money

 

[himzluvhishallie]

Then if u cant get a hps and mh light 2gether then get jus a hps for now and use ur cfl for veg.

 

[markman12]

ok whats a hps..and my plants r u the veg stage

 

[himzluvhishallie]

ok let me try n make it simple....u want basically a BLUEISH light for da 1st stage of growing and then a ORANGEISH one for da 2nd stage...u dont want "soft white" dat a ORANGISH...