light help please

I been reading so much. New here hi everyone great forums. Im a newb at this. I read so much bout light. I got a 6' by 4' grow space. I ana grow 3 plants what bulb to you. A flourescent 150w be enough for 3?? Thanks for replys!!

You should go big or go home if you have the money. Depending on how your grow space is set up (cabinet, closet, tent, etc.) I would go with a 400w or 600w HPS with proper ventilation of course. Otherwise, go with a 150w or 250w HPS if you want to spend less than $140ish. If you have even more money, you can buy a metal halide conversion bulb if your ballast or light can take it.

I found a 250w with 6500 k. For 80$. Hows that?? Its a cfl

Also if i got 400w wouldnt that be alot for 3 plants?? How far would a 400w bulb be kept from seedlings?

If you have the money, go with a 150w HPS or 250w HPS and screw the CFL's. A 400w HPS could probably get you about 6-8 plants with 6 being the ideal in my opinion. You would want it around 28" above to start and then lower it from there as your plants get older with a 400w HPS. How much do you want to yield is the question? Your grow space is 6 feet long by 4 feet high? If that's the case, then go with a 150w or 250w HPS.

I run a 400 watt in 3 X 4 X 6 grow box. I have grown 4 plants in it, but they were a little crowded.

Right now I have 3 going this time.

Ok
Im not sure. This will be my first grow so as long as i yeild i be happy.

So i assume you meant higher as they get older right.

Ok 6 plants 250w hps and keep it 28" from seedlings??

timeismoney1 said:

Ok
Im not sure. This will be my first grow so as long as i yeild i be happy.

So i assume you meant higher as they get older right.

Ok 6 plants 250w hps and keep it 28" from seedlings??

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Heres where your CFLs come in. 28'' is too far but any closer and they'll get too hot under that HPS. So its best to use CFLs for seedlings, probably about two weeks under CFLs, as close as you can get them without burning. Then when they're big and strong, you can transfer them under your HPS, although MH is better for vegetative growth, an HPS will work fine.

A 150w HPS covers a 2 x 2 area.
A 250w HPS covers a 3 x 3 area.
A 400w HPS covers a 4 x 4 area.

6 plants under a 250w HPS might be a little crowded. I would probably do 4-5 max. Again, this depends on the height you throw them into flower at. If you want to grow 6 plants, go with a 400w HPS or higher. As for the height you place your light at for seedlings, it depends on what light you go with. The smaller the light, the lower you can put the lamp to start.

Edit: They recommend putting a 400w HPS 3-4 feet away from seedlings. I found this a little much from experience which is why I started mine at 28" with no problems.

Math will help in this situation---- you need 2000 lumen per foot squared. Multiply the width x the length to give square footage-----4x6 24 feet 24 x 2000 =48000 Lumen. Minimum. That is keeping the light with in a foot of the tops. So it is the cost per Lumen you are looking at 250 watt gives off how much lumen for 80 bucks? I get a 4 pack of 23 watters for about 7 bucks they out off anywhere form 1300 to 1600 per bulb. Sometimes 2 400's are better then a 1000 for light position heat etc..../ I have a 4 x 2 veg area I run 11 bulbs and a flower area same size with 16 bulbs. See pics Light requirements were hard to find in here when I looked back in late 2009.

A 400w hps wont actually cover a 4x4 foot area as the sole and primary light source. Minimum foot candles for acceptable growth are about 4900. at 24 inches from the bulb (the furthest outside area WITHOUT including the additional distance from the bulb not being completely parallel with the plants unless you are doing a vertical grow) you get about 3979 foot candles.
Let's say you have your 400w HPS only 10 inches from the top of the plants. The maximum distance which is adequate for growing from a 400w HPS is 21". Do the math and you get a 36x36 inch foot print of suitable light for a 50k lumen 400w HPS.
Blah blah.. blah blah blah. A couple 250's would cover that area better than a single 400 but not as good as it should be to use the whole area. A couple 400's would probably be best for your money without going into higher watts (and still wont cover the whole area without supplemental lighting).

So i got 10 sq ft. So 50w times 10 sq feet will be 500w. So can you use hps in the seedling stage?

I figure i buy to 400w hps

Yes, you can use the 400w HPS from start to finish. The recommended starting height for seedlings is 3 to 4 feet. However, I placed my light at 28" with no problems to start. I wouldn't go lower than 20" if I was to start a grow right now.

timeismoney1 said:

So i got 10 sq ft. So 50w times 10 sq feet will be 500w. So can you use hps in the seedling stage?

I figure i buy to 400w hps

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As bongmarley2009 said yes you can.

But if you have a few extra bucks, get a few CFL's for the seeding stage. They work really well and they are cheap.

Time,

Seedlings and clones have a hard time handling the heat and intensity from HID lights, so I would advise that you get a seperate light for them and grow them in a different room. You can pick up a flourescent ballast and a couple of bulbs at wal mart for about $20, and that will work just fine for seedlings or young clones.

As for the growing, a 400w HID is fine for about 4 plants and starts getting marginal at 6-8 depending on how bushy/big they are. If your planning on growing short plants then a 400w should be able to handle 6-8 all the way through flowering, but if they get much over 2 1/2 foot tall your going to want to either add another light, or upgrade to a 600w so that you get a larger coverage area and better light penetration to the lower branches. I personally use a 400w MH for vegging (up to 8 plants at a time) and a 600w HPS for flowering (6-8 plants at a time depending on size/strain), and it works wells for me. I veg to 24 inches, then flower to somewhere around 4 foot (I havent grown any serious sativas yet-my guess is that i would need to drop down to no more then 4 plants per light if they were going over the 4 ft mark.

Note- the reflector you use does make a difference in terms of coverage area, though it doesn't change the total lumen output of the lamp. You can get a reflector that will allow a 400w to cover an area big enough for 8 plants that are 4+ foot tall, but your going to get fewer lumens per sq ft and not have much light penetration to the lower branches. If you go that route I'd suggest using a technique like scrog (screen of green) or one of the methods that involves sacrificing the lower growth to concentrate on putting out one huge cola. Either that or get some supplementary lights for the sides.

Ok
Just went to walmart.

There fluor bulbs are

40w
6500k
3000 lums.

So if i get two would that be enough for 4 seedling plants??

timeismoney1 said:

Ok
Just went to walmart.

There fluor bulbs are

40w
6500k
3000 lums.

So if i get two would that be enough for 4 seedling plants??

Click to expand...

It really depends how close you can get them. You might instead get 4 23 watters for better light coverage, although I think two 40 watters would work too. But definitely make sure you get the 6500k

two of those bulbs would be plenty for seedlings ive seen 10 clones with only 35 watts before with no trouble. also i tend to think that more 250s would be better than 1, 400w because u get more coverage and can concentrate the light. buds might not be as dense but would probably penetrate better because you can get them a bit closer. after ive designed a full setup i know see how important it is to cool your lights to control the heat and temps. and i tend to think temp and airflow will make a plant grow better than more light/lumens will. just my thoughts

Ok. Nvm. Ima just get 6 65w cfls start off with a few and add em as nessesary. there 3200 lumed at 6500k

cfls may be good for starting seeds and vegging a bit but you'll want to get a more intense light and more towards the orange/red/yellow spectrum simulating the harvest sun. its worth it if you want to pack some weight onto those branches