I want to put together the smallest grow box I can for a 400 watt hps over hopefully 6 top44 plants. I hope to find a large armoire or something, otherwise I will go plywood. Dimensions will approximately by 4'Wx6'Hx3'D. To cool the hps, I plan on having 8 computer fans, each rated at 88 cfm. (I amk on a huge budget and already have the computer supplies.) Will this be enough to keep the box cool? Also, what are some good ways to make the random plywood box in my appartment look less out of place? How do you light proof the air holes? Thanks guys!
you could make a DIY cool tube and use 2 of those fans to push and pull air over the bulb. not sure how much heat that would pull away but it WILL help. 8x88= 704 unrestricted CFM's, your box is 72cuft so you should have PLENTY of air movement. I have a Plywood box that is 2x2x4, I painted the outside white, put it n a closet with a blanket over it and if anyone asks I say it's my JANKY gun safe.
I found an armoire at 3' 2" wide, 5' tall and 1' 10" deep. Thanks man, I'm glad those fans will work out. My current plan is to have the 8 fans vent into a small top compartment housing ballast, etc and from there have the air just go out holes in the back. If i wanted to make a carbon filter, would my computer fans be able to handle it or would they jsut be useless?
you should just make a square frame out 2x4s and use b/w poly or panda film to cover it. the b/w or panda film is light proof and much easier to make hole and such in. and the plastic poly wont hold as much heat as the plywood.
Alright, got an armoire! it measures 2' deep, 3' wide, and 5' high. I will be using those computer fans to cool it. Should I go with a 400 watt hps, or will a 250 be almost as good and produce less heat?
Gotta order the light tonight, so 400 watt or 250 watt? they come with an 18" bat wing reflector, and I will be using those computer fans with passive intake. for my space (5'h'wX2'd), and for around 4-6 plants, should I get the 250 or the 400? thanks!
get a 250 unless you plan on getting an air cooled hood with a more powerful exhaust fan. It is possible to cool that box with a 400 but defintely not with some computer fans and a batwing reflector. Hope this helped
How many plants are you planning? you are going to be on the outter reaches of a 250 if you push for 2 many plants. I would go with a 400 and a DIY cool tube, You should be able to mount 1 fan blowing directly into a hurrican or bake a round, and pulling as a booster on the other side. that will leave you with 6 should be plenty. To think of it you wouldnt have enough to push into a scrubber with those fans at the end. so you could have the tube sealed so no odor would pass through??? hope my cheesy paint pic helps...
Skip the computer fans all together and mod a Stanley blower if you want to use a carbon filter. They move way more air under load and are fairly quiet. 8 80mm fans will be noisy as all hell in case you didnt know. Axial fans are great at free air flow but really cannot move air once obstructed, rendering their CFM rating useless. I tried using a 120mm x 38mm, 135 cfm fan in my 22 cu ft cabinet and it worked fine with no filters, but quickly became inefficient with them and caused temps to rise. I switched to the Stanley blower ($45 at Walmart) and never looked back.
They are 4 inch silent computer fans. If i go with a 400, I'll have to make a cooltube. I could use a glass candle holder or something, but how would I then attack it to the reflector? What if the fans couldn't push enough air through the tube? My other idea was to just get a sheet of steel and cut pieces to make the bat wing reflector more of a box, and then attach a duct right behind the bulb sucking in. Which would be a better idea?
you could just hang the reflector above your glass, with string or something.... be creative!! if your fans cant push enough air then you need to improvise, try different ways then just my pic. As Giggity said axials arent really that good once ducted. You could put you "push" fan just outside your box with NO ducting behind it and have the "pull" fan the same place, that would free up some CFM's on the one fan and MAY be enough. If not The stanley blower is a KILLER deal at $45.......and the mod is SIMPLE! Check out this post. Stanley Blower Fan Mod - International Cannagraphic Magazine Forums that would prob be your best bet, and the least hassle, but if its not doable than improvise!! you can do it!! good luck!
I'm growing in a similar sized box with a 400w HPS. I've had my share of heat problems =D My box is 22"x31"x61" -- you have WAY more fans than I do currently (but I'm ordering a 565 CFM within 24 hours, and am currently vegging under CFLs) I would say that ~700 CFM (unrestricted) would keep that cool as long as they remain unrestricted. As soon as your start putting in duct work and filters, those fan's won't amount to much. I guess it depemnds on if you're going to do that or not. My fans are 100% unrestricted and allow for light leaks, that will change once I start flowering. I'm running err... maybe 100 CFMs out of 2 PC fans pushing like 30-35 each and a rather weak fan taken out of a space heater. When I ran a temperature test on the HPS with those fans blowing I hit over 100 degrees, but that's due to not having enough intake. When I removed the bottom of my armoire the temps dropped another couple degrees to about 98.... bear in mind you have 7x more CFM's than I do =D You can check out my grow journal in my sig if you'd like. I'm growing 6 plants (3 strawberry haze and 3 green monster). If you can swing 100 bucks, I'd suggest the 8" 565 CFM fan which is what I'm going to be ordering. It's less CFM than you have, but it's still more powerful and will handle duct and filters with ease. http://www.plantlightinghydroponics.com/valueline-centrifugal-fans-c-76_629.html
i have to add my vote for the stanley blower, for a box that small, you will absolutely need a cool tube. Lowe's sells a lasko blower which is the same thing under the original brand. The surrounding fans won't be able to dissipate heat fast enough to keep temps under control.
i used to use a box, and i copied baronvanhooti on here who put a piece of glass that covered the entire top of the box except for the last two inches which allowed air to pass over the light bulb, putting the extraction fan on the opposite side of the whole in the glass ________________________________________________ Fan light | _____________________________________________ | | | | plants
that makes sense! he meansto custom make a hood pretty much but instead of vents you just leave a gap between the glass and the wall..then mount the fan behind the light pulling the air up thru the vent and over the light...problem with that is if the plants are belowe the glas.you will be sucking up humidity and blowing it over the bulb! over long period of time this cannot be good! just stay with the cool tube design! the theroy is great! I have a similar design going but have a few mods to it for my specific needs! go check it out!
Ok if youu are still following thisthread I have some helpful info. I grow in the crawl space under my house. This space is really really small. It is about 2 feet tall so what I did was dig a 2 foot hole and put my 21 inch tall x 20 inch wide x 28 inch long box in that hole. I have a 400 watt hps mh that hangs over the top of my box. I have a glAss lens over my light with four inch ducting. The way I cool my light is by pulling air out of the hood with a Stanley blower mod. This is probably the best investment I've made so far. I can get my plants within 8" of my light and the temps are only 82 or 83 degrees F. At about 12 to 15" the temp is 72 to 75 with the blower on high. The blower only costs $45 at walmart. And my box is opened top so this isn't even running with my fan. Win the runs then the temps drop around another couple degrees.
I think the 400 will be fine in there I have a 400w HPS in a tent measuring 2'8"x2'8"x5'3". You will need serious ventilaion for sure though and a cool tube. Here's an idea for you if you check High Tech Garden Supply I bet you can get a better price on the 400w you are looking for. I have used there products many times with much success and good customer service. Now that you saved a little cash you can buy a real nice fan. Check out Grow Lights, Grow Lighting & Hydroponics - Plantlighting.com they have amazing deals on fans like Vortex and Valueline. I use the vortex but I here valuelines are not bad. Don't cheap out on ventilation you will end up buying it twice and if it fails kiss your plants goodbye. Did I mention to blowers I reference to come with a warranty? The vortex comes with if I remember correctly a 10 year one. Dude if you can't get it all right now save a little longer and do it right. Also as far as your box goes I'd reccomend you buy a grow tent they'd look less out of place then a giant wooden box. I use a Secret Jardin and the labels are very small and can be easily covered. No one sees my tent but I have heard a couple users say that people have mistaken there tents for those portable closets. Also if you search these forums you can find a DIY cool tube out of a Pyrex Bake around that is cheap and works well. Good luck I'm postive you will be more happy if you save your money and buy nice stuff once. Edit: here's the link to the cool tube DIY http://forum.grasscity.com/grow-room-design-setup/184802-diy-best-cool-tube.html
