Design for grow cabinet, need opinions

[Mtnberner]

Hello, I just scored at 3'x2'x6' cabinet and I'm trying to turn it into the stealthest grow cabinet possible. I want my intake on the roof, contrary to the ideal location which would be down low. I plan to get around this by forcing the hotter air down ward in 4 inch PVC with a low speed 120mm axial fan (0-60cfm). So I need a little affirmation that this will work ok before I drill a huge 4inch hole in the top. I also am worried about keeping this warm in the cold uninsullated garage, so I have also been thinking about placing a small 200w personal heater or 100w infared heat bulb up on top by the intake, for when the lights are out. This heater would be plugged into a thermostat inside the cabinet and hopefully wouldn't be too direct of a heat blast on the plants since the fan is pushin it through 5' of PVC. What do you all think of that, does it sound like it will work? I'm a planner and one who likes to draw out whats in my head, so here's a sketch of the setup I'm thinking about doing, let me know if there are in fatal errors in my design. Thanks very much, this is the best forum on

 

[TIDALWAVE]

Introducing heat in that manner will keep humidity way down!! Maybe even lower than you want?... Maybe in the 10%-20% range if I had to guess. I just built a stealth cabinet myself that is almost exactly the same as your dimensions. I run my lights through the night and it keeps the cabinet at 77-81, if they were turned off at night the box would drop to around 62. I also do not ventilate out of the top, my scrubber hangs from the top and sits at the front of the cabinet just above the lights. Another thing to think about is maybe putting your outlet choice on the outside of the box. I did and it looks a lot better than having wires all over the place hanging in your way, can become a real inconvenience with limited space.

Overall the box looks great!! Good job drawing out and planning!

btw here's mine https://31.media.tumblr.com/03d8134c340d44383601af99237c6829/tumblr_ng7x66uKiH1tllp31o1_1280.jpg

 

[Mtnberner]

Thanks for the advice tidal wave!, I like your cabinet, where do you ventilate if you don't ventilate out the top? The way my cabinet will be situated you will be able to see the sides very well, and you would see any light that leaks out the back reflect against my white walls. I will mount the power strip on the outside, it makes sense not to have all that electrical inside,( I was only going to do it on the inside so i could run a plug-in thermostat for the heater).

I also was thinking about running the lights 24/7, or maybe getting a cheap 400w hps for the winter and a cooler running LED light for the summer.

This will be my first grow, I'm looking into possibly doing auto flowers, will this work with the lights on all the time? If not , do you have any other suggestions for keeping it warm inside? Maybe just turning off the fans and hoping it stays warm for the few hours of dark? Thanks again!

 

[TIDALWAVE]

I ported a 4" hole in the top of the left wall and run my inline booster fan through this hole and then seal around the edges with a silicone caulk. Same thing for my intake setup except carbon scrubber is outside of the box with a support bracket underneath it.

If it's your first grow then don't push the speed of growth too much. The dark hours are just as beneficial as the light hours and plants prefer no interruptions during this time. Do all of your maintenance and work during the lights on time in the cycle. If you do auto flowers then you will only have a short amount of time before a 12/12 light cycle is introduced to the plant. I run 15/9 until the plant has showed the very first sign of its 3rd true leaves then I run an 18/6 cycle. Have thought about running a 20/4 after week 4 or 5 just to see if a 1-2 week duration using that light cycle will enhance growth but not over stress the plant. I will follow the 20/4 light cycle and then go back to a week or two of 18/6 then it's flowering time.

The heating issue is most likely gonna be something that just takes trial and error to figure out. HPS in the winter is a good idea if your running into issues with the temp dropping. You'd be surprised how well a sealed box can hold heat and retain it after the lights are off. What is the exact temp range that your shop stays at during the winter?

 

[TIDALWAVE]

Is there any way the box can sit above the floor about 3-4"s? If so, use that space to use heating pads or some sort of insulation that promotes heat. The heat will travel from bottom to top and stop cold air from flowing underneath. That will help while your lights are off.

 

[Mtnberner]

You're awesome tidalwave, I can space it up I think, I have a couple 4x4 pressure treated posts a can lay underneath it. I could just pile junk around the base to keep it stealth looking.

I haven't paid a whole lot of attention to the temps in my garage until recently, I have had temps as low as 28 degrees Fahrenheit so far this winter, with more of an average around 40 degrees (and about 50%-70% humidity). I imagine it could get as cold as 20 if there's a strong windchill outside. Lets not talk about summer either lol, it gets as bad as 110-115 degrees inside (I need to ventilate the garage badly, which I plan to fix in the summer).

Now you said my original heater idea would make the humidity very low, could I just foliar spray the plants with plain water, when the lights went out? I haven't researched controlling humidity yet, maybe I could add a humidifier? I don't know I'm clueless about humidity at this moment, there's just so much research to do on growing haven't had time to look into it yet

Thanks for helping me

 

[TIDALWAVE]

You can but foliar feeding with plain water at night wont do any good... At least I have never seen it be beneficial. The plants are gonna be drinking the water while the lights are on and anything that is applied to the leaves could possibly burn them due to the intensity of the light. I play with my temps so my plants drink more of a certain nute and then back off to a slightly lower temp for the days they only drink H2O. I never go over 80-82 and once flowering begins you wanna really watch temperature spikes cause the plant thinks winter is near and doesn't like the idea of more heat. A lil trick to get your harvest quicker is to slightly lower temps towards the end of the flowering cycle to trick the plant into finishing quicker.

It does take a lot of research and a good overall understanding of the biology behind plants. I will say this, research research and then yes research some more. But don't be afraid to jump in and learn either, a good plan is always better than going in blind.

Humidity shouldn't matter really as long as it's not falling out or shooting up. I fluctuate mine between 33% and 55%. High humidity can create a habitat for bad things!!

I really wish someone more experienced would chime in, I'm not a pro just done a lot of research and treat my grow like a hobby I want to perfect for personal satisfaction. I will say this though, the temperature spikes your garage could experience will likely cause a lot more monitoring on your part and more cost as well. No way to put a grow box in a closet?

 

[Mtnberner]

Oops, I might have miscommunicated what I was trying to accomplish by the foliar spray, I was thinking of doing that just to increase humidity, not to feed the plants. Anyway, I know it would be awesome to put it inside, I might have to bite the bullet and find a spot for it. I was going to mount a temp monitor on the outside of the cabinet, with the actual probe on the inside so I can monitor temps without breaking the seal and losing left over heat from the light. Like you said I think I'm just gunna have to jump in and see how it goes, figure it out on the fly, I ought to be able to keep temps where I want I will just have to work on my humidity.

 

[TIDALWAVE]

Try soaking a wash rag and then ring it out but not too much. The trick is to maybe mix lets say 1 cup of water with 2-3ml of 3% hydrogen peroxide, this should keep any unwanted mold/bacteria from forming. I've never used this but I have tried it to see the changes, 15%-35% increase depending on dampness temps and the overall size of your grow area. I think its a safe way to increase humidity and still remain sterile inside your grow area.

Whatever you do be very careful when foliar spraying, even if it's just water to increase humidity. MMJ is so sensitive that even the best of intentions can be met with a not so good reaction. Keep water and nutes in the soil or your reservoir when doing Hydro grows. I'm a DWC guy so my plants react a lil differently than a soil plant will but when it comes to anything above the media the rules are nearly always the same.

One more idea that I use for hatching seedlings is to wet a rag with a water/H2O2 mix then lay it over a heating pad. My lil seeds sit inside a rockwool cube or a jiffy pot on top of the rag and pad, hahaha rag and pad lol... Sorry... Keeps humidity in the 80% range and heat around 82F. Those numbers only apply to my smaller area underneath the main grow and this is with no ventilation or fans on.

BTW your temp idea is perfect. It's a common practice for some and I'm sure there are videos/journals that can show you how other people installed them in their grow area. One thing to consider is what will the temps be at the top, middle and bottom of the box? I have great ventilation and there is still a difference between top and bottom. I check temps at the top of the plant and adjust according to their height in the grow area. No need to freak out cause the temp differences are not always big, just some food for thought.

 

[LEDBud]

Co2 is heavy , any collected co2 from breathing etc etc would be on the floor as co2 is heavier than air , if your intake was off the floor surface you would scavenge any available Co2.

As a side benefit the floor air is the coolest and already at the bottom of your grow box , which also encourages the natural air flow from bottom to top with the fan off.


I also suggest making a 2nd floor 6 inches above the bottom floor , so you have space for airflow under the grow box.

Use it just for breathing room or add a drain and put a catch pan under it.


I did it this way its working very nicely

 

[Mtnberner]

Thank you ledbud, I knew about the natural airflow of warm air raising, but i didn't give any consideration to c02, so thanks for bringing that to my attention. The cabinet has a 4 inch false floor, that I could make a stealth vent in, but I'm in a fairly old garage, and that's where all the critters hang, I worry about them getting in down there, even with a filter screen installed, (I'm sorta planning on bug bombing a month or so before I begin, but would rather not if you all think its not 100% necessary). So ledbud, do you thinking i would be doing a huge disservice to my grow by not having the intake down low? I already bought the 4 inch PVC for the intake, but I could take it back if its going to be too detrimental to the grow. Thanks again!

 

[LEDBud]

I don't think it will matter to much at all for you , if at all as the Co2 concentration on your garage floor would probably be minimal anyways.


I found it useful to do because I will be using Co2 amendment to give the plants their Co2 supply as I will be using a dehumidifier instead of venting this winter.

In your case having fan's blowing fresh air over the plants will supply them with plenty of co2 , the fan's will speed up the leaves access to the co2 in the air , they like the wind for this reason.

 

[Mtnberner]

All right I think I might start drilling holes now then, I'm still up in the air a little wether to go with the platinum p300 or p450 for the light, that's my last purchase to make along with getting seeds. I want to get a light setup that I can expand on and double my operation if my first few grows go decent enough. ( thinking I might upgrade from my 2'x3' area to a 4x4' area if all goes good and keep the the 2x3 cabinet for clones or seedlings). After successful germination I will probably start a journal.

 

[LEDBud]

I think for a 2x4' rectangle grow 2 300w panels would be ideal and with a square 3x3 one p450 would work well.

I myself like the idea of using 2 lights in a 2x4 area but that personal to my situation. I will be using two 432w (230w) led panels in a 2x4 plywood cabinet for flower although two 300w would be plenty / lot's of light.

 

[LEDBud]

I suggest keeping the lights 6" to 1ft. from the tops of the plants the closer the stronger the light , every 6 inches you lose half the light power , that's a high price to pay in par light.

 

[Mtnberner]

I was leaning toward getting one P450 now for my 3x2 area, then getting another P450 when I expand, making that 2 P450s in a 4x4 tent. I figured the PAR numbers were so high on those lights that I would be able to hang them 18" above the canopy and get a little more spread of light, but if this isn't the case, maybe I need to rethink my lighting, possibly look into hps. (I could only probably talk my wife into letting me buy two led panels, I know they are cheaper in the long run, but she can't get by the initial cost comparison).

 

[LEDBud]

HPS are no different then the LED's they lose light power just as fast , and the PAR light is lower per watt.

If you want a good estimate of the lights spread and how it changes with height , take a 90 degree angle / carpenters square and flip it upside down and you can see the spread the LED panel will illuminate at 1ft. height. Most people keep them at a extra height to achieve more side lighting , it would be more productive (imo) to crowd your plants in a tighter area and pound them with light.

I am someone who uses close lighting so I can't help but suggest it to others , it may not suit your style as it is a bit of a odd way to grow , I'll be the first to admit it.. but hey it works and science backs it ha ha.

 

[Mtnberner]

Thanks LED, that was a very helpful post, I was wondering about plant spacing myself, your way of having the plants close together and pounding them with light does make sense to me, the best PAR is in the center and not the side lighting as I understand it.

 

[LEDBud]

Two p450 (270w) may work nicely for you in a 4x4 , a 3 x 4 would fit more evenly with the panels rectangle design. Your 2 x 3 area would work very well with one p450 , a perfect high output match really , with a 3 x 4 area for two lights being equally as bright over the garden , at about 1ft height.

you could use odd sizes like 2.5 ft x 3.5 ft or 3.5 x 4.5 and still be fine.

 

[Mtnberner]

P450 it is! I went to some local hydro shops thinking i could at least see a few different led panels in person, boy was I mistaken! I went to 3 different places, everyplace said they were pretty much junk, I'm assuming they all had bad experiences with old technology when they first came out on the market now they've wrote them all off as junk, not trying any of the newer tech. Do you think that's an accurate assessment? That just shocked me, cuz up until now I thought LED was the thing (going by what I've seen on the Internet). I trust what I've seen on these grow journals enough to give LED a shot though.

It's funny one place said there was only one good led light they knew of and that was the KIND lights, which from my research can't match the PAR of the platinum lights and are way more expensive at then same time. He said eventually he thought LED would be better then HPS, but he said they just weren't there yet. Well I think they are, just maybe not at a competitive price point, from the initial cost stand point.

Makes me want to open an all LED hydro store with quality lights, and give these old school shops a run for their money, lol!