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Grow Box - Questions.

Toleman

Toleman

Well I have built myself a grow box to house some seedlings until spring

Its basicly a cardboard box 2' x 1' and 1.5' tall. I have lined it with 10mm (just under 1/2") polystyrene as insulation and light reflectivity. Im not sure how reflective it is though? I have ran out of 10mm polystyrene so the bottom will be lined with some 25mm (1") stuff I have.

I have ordered 2 pc fans, one for drawing air at the bottom, one for extraction at the top. I have a 12v transformer for powering them.

The lighting is a 2' T8 shop light (2 x 18w) - do you think this enough for 2' squared? I can always add a couple of 20w cfl's.

The box can fit a maximum of 8 6" pots so eventually it will have 8 plants in but its just seedlings for the minute.

P031109_1956.jpg


What do you think?
 
My personal opinion is that heat/electricity and cardboard are a scary combination......I'm sure it will be fine, but as an electrician, it just scares the hell out of me...:)

The 2 18 Watt tubes should be ok. The issue will be heat retention but should be ok i guess....what style of tube are you using?? You can get grow tubes for the 18 watt lights....
 
Hi Moyboy. Im using Daylight tubes but I have warm white so maybe a combo of 6400, 2700?

I also have some experience with electricity, I did a year at college but needed an apprenticeship to go any further with it.

The tubes are cool running, the cable is secured so connections can't be pulled loose and the house is fitted with a 30mA RCD. I know there is a very small potential fire risk but its greatly minimised. The light is also going to be suspended mid box from 2 light hangers. These will be attached to the underside of a desk above and the flaps on the box adjusted for ideal temperature.

Chris

p.s the plug top is fitten with the correct fuse (3A) and the cable is 2.5mm capable of upto 20A.
p.p.s its going to be in my bedroom so temps shouldn't be a problem (Still living at home)
 
Toleman said:
I have ordered 2 pc fans, one for drawing air at the bottom, one for extraction at the top. I have a 12v transformer for powering them.
Click to expand...

Im doing something similar with mine, but am still puzzled as to how to power the fan(s). Id usually plug them into a computer motherboard or power unit.
I know I can pick up a small transformer or even use a cell phone charger......

But how do they hook up?

Cut off the connectors and rewire into different connectors?
 
We both seeking the same info Tole, looks like we are doing the same thing ;).

I read between 20C and 30C is good, 28C being optimal for most.
Ill wait until my lamp has arrived to see how much heat it generates before i tamper with heat. I reckon my tub will get too warm if its left on for several hours.
 
I don't know about the wattage per square foot but the temps that Wunder stated are pretty good although I wouldn't want to go below 25C when germinating or you will get a higher fail rate......28C is great!!!

Most chillis are not to worried about a few degrees either way, but over 32 and under 25 isn't good.......Superhots can be a little more sensitive to temp variation and like to be at a set temp which is around 28-30C in my experiences
 
folks can get way to anal with temps and the likes, i never have and prob never will check the temp in my box, i no that it ain't up near 25 prob not even as high as 20, but the seedlings in there don't seen to mind,
Chris you say how many pots will fit in but you've gotta remember the spread of the plants
My box can fit 30 3" pots (square ones) but as the plants get to full term in the box you'll be lucky to fit a dozen in there
 
Might reduce to 6 then. :)

Currently only using one fan at the top sucking heat away. Should be enough to stir it up a bit.

Might add the other when I can be bothered with the mess of crumbled polystyrene.

Chris
 
yea you could just have passive air flow, poke a few holes around the bottom and have the fan exhaust the heat at the top of the box thus drawing air in through the holes.
 
Toleman said:
Try Ikea and Wilkinsons. I got this from wilco for £4 - its 50 litres by the way.
Click to expand...

Are you going to use that instead of the cardboard box? Cardboard is very flammable and also weaken with the humidity.
 
nope still using the card lined with polystyrene, Seems to be working fine so far.

That plastic tub is going to be the reservoir for my hydro system - I was just showing whats available for cheap.

Chris
 
Toleman said:
Answered on FF forum Wunder.

Chris
Click to expand...

Uh What/where is that? Sorry for the noob question.
I'd like to set up some little fan thingys too.
Would you please show a pic of how the box looks in your room now?
I would be more concerned about circulating the warm air down around the plant's bases to control dampness. But...
 
Disclaimer:
Im no expert on this and its my first grow box im making.

But, on a PC, which is essentially a ventilated box with microchips in, you push out warm air at the top and rear, and pull in cool air from the bottom and front. Thats how you get a good airflow going through.
The warm air is going to rise, so you exhaust from the top.

I think the thing with a grow box is not so much the temperature (as in PCs) but not having any temperature focussed on one point under the lamp, hotspots.
Also you are going to want fresh carbon dioxide coming in.

I plan to have one 120mm PC fan at the top of the box, and a similar sized hole on the bottom of the opposite side. This should keep the air circulating and bring in new air.
If it doesnt seem to be working well enough ill add another fan over the lower hole to increase air intake.
 
Hi ABM,

FF stands for FireFoods and is a brit-hosted forum but everybody is welcome.

You need a 12v transformer of some kind. I presume your in the States so Radio Shack might be your best bet. You want either a 12v transformer or a variable one which you can change voltages on.
Something like this:
http://www.maplin.co.uk/Module.aspx?ModuleNo=32746&C=SO&U=strat15

Alternativly an old ac to dc adapter which you may find in a draw somewhere, commonly used to power things like Radio's, modems, laptops, ect. Even a 9v - 12v phone charger would work. It must be AC to DC though. Then cut the plug of your fan. It will either have 2 or 3 wires going into the main body of the fan. These are normally red and black (plus yellow if 3). Ignore the yellow if its there, cut it off or tape it up, its for speed monitoring when used in a pc. Connect the red and blacks to your power supply with connector blocks or crimps and you ready to go.

P101109_1646.jpg

P101109_164601.jpg


Sorry for the poor pics

Chris
 
ok Thanks That's pretty cool! I need to make one or 2 of those.
I just thought you would want to push the warm air down towards the plants. I want to do a study.
Great pics actually.
Tony
 
I thought about drawing air low and pumping out at the top but I then realised this could make it too cold. The fan on the left is sucking in and the right is removing. The fans got enough blow and I can feel the breeze from it at the bottom of the box. The air in theory should be doing a U shape.

Its not the neatest thing ever but it does the job.

Chris
 
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