Would 1000w hps be too much light for 4'x5'

[Daneel]

I have about 11 plants in a four by five foot room. I have an eight inch exhaust fan near the top of the room and a large air inlet hole to allow air in. The ceiling is about 10' feet high. I'm currently using a 400w MH light now but will switch to flowering soon. I have a 1000w HPS light available and am thinking I might use it instead of another 400w HPS.

A second question would be should I switch to the HPS when I change to 12/12 or should I leave the MH on until flowers start?

 

[Hydro-Soil]

Your concerns should be around heat. IF you're able to bleed off the heat of a 1K HPS, that's a nice sized footprint to grow on.


The MH will keep the plants shorter and bushier and the HPS will pack on the most budweight. Switch to HPS within the first week of flower and you'll be fine.

 

[ChaosCatalunya]

4x3 is 1M2, 4x5, 1.6M2, 1K is easily fitted in there, if heat is not a problem.

If it is, cooltubes etc can help, or just siting your exhaust/filter right by the light... take it from the hottest part of the room.

 

[Lazyman]

Yeah a 1000W light gives you 50 watts per square foot on a 4.5' X 4.5' footprint, so you should be fine. I use 4X4 trays, and can fit:

36 8-10" tall plants
25 12-14" tall plants
16 16-18" tall plants
9 22-24" tall plants

Remember most strains stretch to at least double their veg height in the first 3 weeks of flower, but if you prune when you flip (tops and low branches) and again at 2 weeks into flower, you should be ok.

 

[NorCalFor20]

4x5 is a bit larger than most would reccomend for a 1000w hps,

i would use 1,000w for every 4x4 space, but you should be fine running 1kw in a 4x5

 

[PkRipper]

most important is light placement. you should use the blub in the middle of the 5 foot length , split the 5 foot lenght of the room with a line you draw on, now get the bulb on that line,,


use a 4x4 table and under the table , were there is the extra foot space in your 4x5 foot area you can place large potters and use sum of your left over res water to take care of that one row of large contanier plants......




btw i puffin fullmelt at the momment so i dont know if this even makes any sense

 

[DrBudGreengenes]

4x5 iz fine for a 1K
5x5 is perfect...if U have sides to reflect light back
Too many ppl think a 1K is only good for a 4x4 footprint..cuz they Hang them in open rooms
and waste ALOT of lite by only using it one time​

 

[FreezerBoy]

most important is light placement. you should use the blub in the middle of the 5 foot length , split the 5 foot lenght of the room with a line you draw on, now get the bulb on that line,,

Only if it's on a mover rail, otherwise turn the lamp 90º. Lamps throw light sideways, not forward or back. What they throw forward is a black spot. You want the lamp parallel to the short side of the grow. This allows you to achieve greater footprint at a lower height.

 

[guest123]

Hmm I run a 7 by 4 secret jardin with 2000. Doesnt seem like too much.

 

[Daneel]

Thanks for all the replies. Good info that will certainly help. Thanks everyone.

 

[DonkeyPunch]

I ran a 1k light in a 3x5 tent once. (Not a real tent, but one made out of panda polly and 2x4, with two stick on zippers to make a door.)

I had an air cooled hood, that sucked air out of the inside of the tent through a carbon filter, through the light, and blew it outside the homemade tent. This created a negitive pressure environment that sucked in plenty of air from the rest of the house that is air conditioned.

My air temps were fine, but I had serious water temp issues. I even tried wrapping my buckets in some duct insulation that was reflective, but my water still wanted to stay 78-80. I tried freezing a ton of milk cartons and swapping them out in the main res which was outside the tent, did nothing for temps. I am sure a chiller would have solved it but was not ready to drop the coin on it, and I just decided to downside. All I need is 2-3 ounces a harvest for my use. Decided to just say fuck it to the extra 1k-2k a month of income idea I had, which is probably a lot safer for me as well.

Also, I had my pump in the main rez, and not in line and that may have caused my heat issues.

Your design may be better than mine and work fine, but those are the issues I had with something that sounds similar size wise, and wattage wise.

 

[dotblunt]

I've a 6x7 footprint and run 3800W during peak 12/12, your 4x5 is just adequate for a 1k and will get you some fairly nice sized nuggz...you can always stagger your harvest to allow the lower buds to firm up after cherry picking all the nice colas. If I had your setup I'd run the 400W as well, I've 2800W HPS and 1K MH and so far I love the complete light the combination gives. With 10' ceilings and winter coming you shouldn't have a problem with heat, but if you do and still wish the extra light of the 400W just try running it for 6 hours in the middle of the 12 'on' period.

Good Luck!

 

[Daneel]

DonkeyPunch and dotblunt: Thanks for the input and information. I hadn't thought about running both lights or about cherry picking the big buds off the top. As for heat...I live just south of the equator in Southeast Asia so I won't be getting any cool winter weather. During veg my grow room hovers in the low 90s with my exhaust fan on. However, it is a humid heat instead of a dry heat that you would get in North America so it doesn't suck the moisture out of the plants. My grow room is a 4x5 closet in a spare bedroom. The bedroom has its own AC but for the time being I am only using a room exhaust fan which I installed in the wall of the closet venting to the outside. I could run the AC if needed but would rather keep electricity costs down if possible. It still remains to be seen if this will be a problem during flowering. If heat will be a problem what symptoms should I look for during flowering? No flowering? Spots? Wilting? Lack of growth?

 

[darksith]

If you have the right walls and the right shade you can have a footprint of 8x8 easy with 1kw hps. Pulling almost 2p a light in that room.

 

[bostrom155]

If you have the right walls and the right shade you can have a footprint of 8x8 easy with 1kw hps. Pulling almost 2p a light in that room.

How far away would the light be from the plants. I have 2 - 1000's and i'm always thinking the light is never close enough. I'm covering a 8x4 space. I'm about 18-20 inches above canopy now.

 

[Daneel]

Right now I'm still using my 400w MH but will switch to 1000w HPS about one week into flowering. Will probably be 12 to 18 above the plants if not too hot.