70W HPS in a grow tub?

Hello there, i'm a new grower who has little in the name of space and has to keep this whole operation relatively low key... i've decided to start a stealth grow in two hollowed out speakers for the seedlings (they also have nice potential for clone boxes in the future if all goes well!) When these plants soon outgrow the speakers, i'm going to move them into a Rubbermaid 'DIY grow tub'... essentially it's just 3 of the large snap-on-top tubs stacked over each other (total dim's: 29" x 20" x 49"), light sealed, mylar-lined and fitted with a carbon filered exhaust with passive air-intake. originally i was thinking of doing the entire grow with CFLs, but now I'm thinking about going out to buy a 70W HPS to compliment the flowering stage and i was curious if i could run into space and heat problems if i did.

Could i use a HPS bulb -one as low powered as 70 watts- in such a small space? and if i did how small would i have to restrict my plants in order to keep the HPS bulb at an adequate distance from the plants? i understand users of the higher-watt HPS bulbs keep them about 20 or more inches away from their plants.

Any thoughts?

Well, for small spaces, I would definitely recommend clf's, but I have comfortably run a 70w HPS in a pc grow.

~ooli~

Really? how did your PC grow go?
i have planned on using CFL's for this entire grow given the small space i have to work with, but i want to try and reach this method's full potential... I think a 70watt HPS bulb would help me get there, or at least get closer if i can manage to keep the plants from getting burned and keep the grow space's temps. within reason.

lsdhighway said:

Really? how did your PC grow go?
i have planned on using CFL's for this entire grow given the small space i have to work with, but i want to try and reach this method's full potential... I think a 70watt HPS bulb would help me get there, or at least get closer if i can manage to keep the plants from getting burned and keep the grow space's temps. within reason.

Click to expand...

I grew once with a 70HPS.. Wasn't very impressive. Depending on how many CFL's you can fit, I would consider them.

Do these small watt hps bulbs work without a ballast? Do you need to get a sefl ballast base for them? How do the work? Very curious. Thanks

I've never used a 70 watt hps, but if you can use it without high temps in your box, I'd recommend it. You will have a little bit better quality light, but mainly you will get that light from using 70 watts, where the same amount of light from cfls will use more electricity. Best thing you can probably do is set up your grow space and experiment and see what will work better for you. Keep in mind that multiple cfls will usually require more space. A single 70 watt hps will be a single fixture, leaving more room for bud.

A concern of mine is the heat coming from the bulb. i understand those owners with 250/400watt HPS bulbs keep them at quite a distance unless they're on a moving track... is the heat from a 70watt bulb drastically less?
would i be able to keep this bulb 6 inches away from my plant tops if the temperature in the space was under control?

lsdhighway said:

A concern of mine is the heat coming from the bulb. i understand those owners with 250/400watt HPS bulbs keep them at quite a distance unless they're on a moving track... is the heat from a 70watt bulb drastically less?
would i be able to keep this bulb 6 inches away from my plant tops if the temperature in the space was under control?

Click to expand...

In a word....yes you could. I am running a 250 watt hps in a euro vent hood, and my plants tops are touching the glass on the hood, and they're not getting burned. The key is airflow - I am running a can filter on one end of the hood, and an inline fan on the other side. My entire vent/filter system is a straight shot except for a single 90 ish degree bend. With my set up I could probably run a 400 and have the light almost touching my plant tops. I'm not sure how hot a 70 watt hps will get, but if its all enclosed in your grow cab, even a few cfls would make it too hot. Filtered airflow in and out of your grow space is the key.

I am currently using a 100 hps i bought at home depot. Its an outdoor unit so it is sealed nice. I cut two holes, one for intake, one for exhaust. This way all the heat is collected in the housing and immediately vented. Keeping my box kool.

id get one of those 12" square 1" thick 45 watt lcd's no heat and itll leave you way more room up. i found them for 120$ and they put out way more usefull light than a 70w hps.

70w hps i would think would put out a good amount of heat for that small space. id add plenty of air in and out. maybe try using 120mm computer fans their quiet. most anyway and all youd need to do is ask an electrician here how to wire it to 110 or is that 120? ya im high...

02ws6ta said:

I am currently using a 100 hps i bought at home depot. Its an outdoor unit so it is sealed nice. I cut two holes, one for intake, one for exhaust. This way all the heat is collected in the housing and immediately vented. Keeping my box kool.

Click to expand...

thats aweosme man, i'm going to Home depot to pick up everything for my entire operation it seems lol.
what area of the store did you find it in? i can only find a 70watt HPS bulb, i cant even find the ballast for it within the store... too sketched out to ask any of the workers thre about it, i'll suck it up and ask about it soon :S

Home depot doesn't carry ballasts or ballast kits unless you buy one of those flood lights everyone is talking about. Go to an electrical supply store and you'll find whatever you need at a much better price.