Twin 70w CMH Cab

[Gnz]

Today I decided to bite the bullet and replace my flower cab (it's going to become my new veg cab), since switching from CFL to CMH I've been battling light and heat stress issues and have decided the only fix is a little more floor space and head room.

Plus it gives me the excuse to build a tidier, more organised cab than my old one.

I bought the cabinet below, its flat pack mdf with a white plastic veneer. Internal dimensions of each half are roughly 400mm deep x 800mm wide x 800mm tall, or just under 3.45 sq ft.

Light currently comes from a 70w double ended RX7s CMH bulb in each section, one at 3000k and one at 4000k as it's running some plants which have just flipped. I'm going to add a pair of 24w 2700k CFL to each section to increase the w/sq ft if I need to.

Air is pulled through a light trap in the base, through a pair of 100mm elbows into the bottom cabinet, then through a 125mm 180cfm inline blower into the top cabinet, where it's pulled out through the top via a 250cfm exhaust fan. I may add a second inline fan to the bottom unit as an intake fan if I have any temperature issues.

Currently running two neglected NL from my old veg cab, and a mystery bagseed all at 3-5 weeks veg, flipped them today because I needed something to put in the cab but they're a lot smaller than I'd usually flip them at. It's also finishing the stressed out bagseed from my old flower cab which is at day 58 and coming out shortly.

I have some foil tape I'll run along the back seams, and some wiring conduit for the wires running along the back corner to finish yet. Remaining light proof and controlling smell isn't an issue as they're in a dark "lung room" of sorts with my other cabs, this cabinet seems to be reasonably light proof on its own however.

Eventually I'd like to have each half of the cabinet running a 10 week strain at 5 week intervals with a single large scrog in each. I may reveg one of the northern lights to achieve this.

 

[Gnz]

Plants are now arranged as below, you can see the colour temperature difference between the 4000k and 3000k bulb clearly in this photo.

Top (4000k 70w CMH 12/12 day 0)
Nirvana NL from seed 5 weeks veg x 2, mystery bagseed 3 weeks veg. These have all been subject to heavy underwatering, the NL on the far left has suffered the most.

Bottom (3000k 70w CMH 12/12 day 58)
Mystery bagseed, this has spent some time under a mix of cfl and cmh along with having a bad stress episode from seeing 200+w in 1.4 sq ft early in flower which it never really recovered from. Still seems to be yielding okay considering how damaged it is, looking forward to trying it regardless!

The photos seem to be rotating themselves at free will, apologies in advance for the neck strain.

 

[MicroRoy]

Nice looking set up. Good luck.

 

[Gnz]

Nice looking set up. Good luck.

Thanks man, hope your projects are going well. That shot glass thread in your signature and the square foot challenge thread in the micro grow forum convinced me to start growing a while ago now, good to see the place still thriving!

 

[Gnz]

24 hours in and the young plants are looking much happier about their new home.

Was planning to run the flowering plant to 70 days but I might go a little longer, day 59 and not showing any amber trichs yet. Will continue the flush and see what happens!

Wiring conduit added and joins all sealed with foil tape, temperature is sitting at 21c/70f lights on so I'm going to add 2x24w CFL's to the top half of the cab tomorrow.

 

[ReikoX]

Nice looking cab there. Hope it all works out for you. This your first time using those CMH? How do you like them?

 

[Gnz]

Nice looking cab there. Hope it all works out for you. This your first time using those CMH? How do you like them?

Yeah I switched to CMH in my old cab when the bottom plant began flowering 8 weeks ago, I only really began to get it dialed in over the last few weeks so results won't really show till the next round presuming no problems with the new cab.

The bulbs are great to work with, compact and don't give off a huge amount of heat, light distribution seems to be pretty good and 70w cmh looked brighter than ~120w of cfl. Will be interesting to see how it does at ~20w/sq ft rather than 60 because 60 was too much.

I have a 150w ballast, so I may end up putting a 150w RX7S bulb in one half of the cab at some point and running 2 x 70w in the other, have some CFL's and LEDs to play around with first but I prefer how tidy the cab is with a single bulb in each half.

 

[Gnz]

Looks like the ladies upstairs will make up for their short veg with super fast stretch, no complaints. Have spaced them apart further and will transplant into larger pots shortly before root growth slows. These plants have all been topped so in this larger cab I'm only planning to do a little supercropping to tame these early flips.

The fan pulling air from the bottom section to the top is giving the plant on the right a gale force battering, going to duct it across the back of the cab and aim for a more even leaf flutter across all the plants. Have shifted everything to the left as a temporary fix.

 

[grouchy]

The fan between the sections may be redundant imo. Adding a couple more passive intakes/light traps in the bottom and just holes in the divider should work well for airflow

 

[Gnz]

The fan between the sections may be redundant imo. Adding a couple more passive intakes/light traps in the bottom and just holes in the divider should work well for airflow

I'll try cutting another 125mm hole in the left side of the divider and remove the fan, I'd originally intended to have 4 intakes so have another set of elbows to fit.

You're right, the top extractor fan should move plenty of air for the whole cab. I'll keep an eye on temperature around the lower bulb and see if it makes a difference.

 

[MiniFridgeLED]

Very nice setup man. I need to get a mother setup and get a super small fridge for on top of my already existing fridge with intake and exhaust holes so I have a dark place to dry the bud as well. Then I can have a perpetual grow. Have 3 to 4 mother's in mind. Question, you ever had NL smell like diesel when touched?

 

[Gnz]

Very nice setup man. I need to get a mother setup and get a super small fridge for on top of my already existing fridge with intake and exhaust holes so I have a dark place to dry the bud as well. Then I can have a perpetual grow. Have 3 to 4 mother's in mind. Question, you ever had NL smell like diesel when touched?

This is my first run of the nirvana NL and at least a month from starting to get smelly, most stuff I've grown smells slightly 'diesel' like in late flower and then mellows out again after a cure. But this is probably a common trait of indica dominant plants.

 

[Gnz]

Coming up to the end of day 62, first amber trichs showing on the larger top buds with more than half of them milky. Lower buds still have a little way to go, only just starting to show a few milky trichs.

I think I'll chop at day 72 right before I'm out of town for 4 days, if the lower buds aren't showing amber trichs by then I'll leave them till I get back.

 

[Gnz]

70w over 3.45sq ft at 12-24" distance was never going to cut it, growth in late flower has been okay but I doubt initiating flower at 20w/sq ft will ever happen.

I've ordered a 150w 3000k bulb for the downstairs section as I intend to continue using it for late flower.

Upstairs is a bit different, the CMH bulb is recessed into the exhaust unit so I really needed some side fill.

I've installed a 24w 1550lm 2700k CFL on either side of the CMH, they're vertical as I plan to replace each with a pair of 18w 2000lm 2700k LED bulbs. For now its up to just under 35w/sq ft but will end up a little over 40.

 

[MiniFridgeLED]

That is so sweet what you got going on there. You should try to get two of those "v" bulb things and put 2 CFLs on each side or just one in each because I have read quite a lot that the majority of the light from CFLs comes from the sides of the bulbs. Just my two cents. I love your set up and most likely will do that instead of a tent in the future.

 

[MiniFridgeLED]

This is my first run of the nirvana NL and at least a month from starting to get smelly, most stuff I've grown smells slightly 'diesel' like in late flower and then mellows out again after a cure. But this is probably a common trait of indica dominant plants.

I have scoured Nirvana's site and have 5 different seeds I want to get from them to try in the future. I want to try some really hardy old school genetics before I branch out and start to grow stuff that people are just now inventing. Thank-you for answering me about the smell it has calmed down some but it may be because I don't move them anymore and siphon my waste water out.

 

[Gnz]

That is so sweet what you got going on there. You should try to get two of those "v" bulb things and put 2 CFLs on each side or just one in each because I have read quite a lot that the majority of the light from CFLs comes from the sides of the bulbs. Just my two cents. I love your set up and most likely will do that instead of a tent in the future.

I'm gonna switch them over to LED or I would definitely have put the bulbs on their sides, I think I'll end up with 2x18w LED on either side of the CMH but I'll see how a single one does for now.

Certainly cheaper than a tent! Only downside is its not so easy to transport or pack away. But for under $200 USD lights and fans included I'm happy.

 

[MiniFridgeLED]

I'm gonna switch them over to LED or I would definitely have put the bulbs on their sides, I think I'll end up with 2x18w LED on either side of the CMH but I'll see how a single one does for now.

Certainly cheaper than a tent! Only downside is its not so easy to transport or pack away. But for under $200 USD lights and fans included I'm happy.

Check these out big dog as supplement. A little pricey but if they worked it'd be great.

 

[MiniFridgeLED]

At 1141 reviews with that high of feedback I normally find it hard to believe they are all bot posts. I looked at those before though and thought those would be great on something like my next pick I will post so you can direct the light anywhere

 

[MiniFridgeLED]

Here they are