150w HPS / DWC - Small-Cabinet Grow

This is my first grow journal as well as my first foray into hydroponics and indoor growing. Feedback/help/constructive criticism/advice greatly appreciated as I'm here to learn. The journal is beginning in week 2 of being in the cabinet - week 1 through 2 photos attached.

The cabinet dimensions are only 34" (H) X 24" (W) X 15" (D). Exhaust ventilation is provided by a $14 bathroom exhaust fan from a home-improvement store rated at 50 cfm. I am using an additional (quite) booster fan at intake (mainly used to keep a small amount of airflow within the cabinet when the lights and main exhaust fan is turned off and if I need to put the cabinet into quite mode). An additional small circulating fan has been placed blowing across the HPS light housing (including the internal ballast) and bulb. The light housing/ballast never gets more than slightly warm. Temperatures in the cab top out in the upper 80s at the hottest points with all fans/lights (incl. CFLs) running... roughly 10 degrees above room ambient temperature. Humidity stays pretty much pegged at 20% due to home A/C use - unable to find a way to raise it due to rapid air exchange inside the cabinet... so not worrying about it unless a problem shows. Exhaust fan may be upgraded along with the addition of a carbon filter later in the grow as needed.

Ionization smoke alarm installed internally (located above the lights and near the exhaust intake). All wiring is above water level. HPS light is double-hung with safety hooks.

I am using about a 20'ish liter Sterilite container for the DWC system, however only 17 liters (max) is usable due to holes for the handles. 2 dual (2 line) air pumps go to 4 airstones. The outside of the reservoir and lid is covered in Panda film. Black silicone aquarium air lines were used for light-proofing the reservoir.

For lighting, a 150w HPS and three 26w (currently) CFLs providing additional light spectrum in the 5000k-6000k range. The interior of the cab is covered in white/black Panda film.

The plants are seed from a random bag that was indica-like with it's effects. Due to my height limits in the cabinet I thought I was just better off with an indica + short vegetative period + LST. Males will be culled with an expected 2 females being kept for final growth.

Would like to try a SCROG grow... as it seems like it would make the most use of the space I have... however, not sure how that would work with seeds and having to cull out males mid-grow. Does anyone do this when growing with non-feminized seeds?

I am using Liquid Karma (LK). LK used at full recommended strength as listed on the bottle for hydroponics. Have not started nutrients but have purchased Pure Blend Pro Grow and Bloom - will likely just start them on half-strength PBP Bloom and not use the PBP Grow at all until I figure out how much of a vegetative growth time I can get away with.

I have had an issue with pH that has been corrected. I believe the water was so base here I burned the seedlings at first which seemed to stunt their growth for a couple of days and resulted in a 'clawing' of the first leaves. Plants otherwise look healthy and are growing quickly since maintaining the pH of the reservoir to ~6 pH with phosphoric acid.

looks good man. try to get those temps down if you can. i'm interested to see how this grow goes. I'm considering going hydro for a grow to see how it compares to soil.

good luck.

peace

crazytrain is correct on the temp.... anything over 80º you'll have problems later on if you don't lower the temps. Mid 70's is best.

Thanks for the feedback. I've been trying to tweak the temperature down - in fact I already bought another 50 cfm exhaust fan to add if needed. But before installing it I wanted to try adding more passive intake area. For such a small space, wouldn't 100cfm be like a wind tunnel in there? The seedlings already 'quiver in the breeze' of the intake. Just trying not to kill the plants... yet, so I've put off doing anything different.

crazytrain, it's cool to be able to watch both the roots and the plant at the same time. It's highly educational if nothing else - but it's crazy how fast the roots grow in the reservoir - which is something I've never been able to see before. I'm having a blast learning and watching the plants grow and feel like a kid doing a science experiment. Beats going out into the middle of a swamp to ninja farm in the middle of summer in any case.

SableZen said:

Thanks for the feedback. I've been trying to tweak the temperature down - in fact I already bought another 50 cfm exhaust fan to add if needed. But before installing it I wanted to try adding more passive intake area. For such a small space, wouldn't 100cfm be like a wind tunnel in there? The seedlings already 'quiver in the breeze' of the intake. Just trying not to kill the plants... yet, so I've put off doing anything different.

crazytrain, it's cool to be able to watch both the roots and the plant at the same time. It's highly educational if nothing else - but it's crazy how fast the roots grow in the reservoir - which is something I've never been able to see before. I'm having a blast learning and watching the plants grow and feel like a kid doing a science experiment. Beats going out into the middle of a swamp to ninja farm in the middle of summer in any case.

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yea man deff beats ninja farming lol but the plants wiggling will help to strengthen and grow a thick stalk to it's not to windy. i know quite alot bout growing just not dwc. i wanna learn so i'll watch and help out wit what i can. jsut try to get your temps into the mid to high 70's and you will be ok. 81 or 80 isn't bad just not optimal.

later bro

Added another 50cfm exhaust fan to the system based on the above advice. Also added another internal circulating fan. Temperatures (res and cab) dropped by 5-7 degrees. I think that's the best I can do until I get a small a/c unit.

good deal man, what are your temps lookin like now?

It looks like I am 5 degrees over ambient temperature at plant level. It's 81F next to the seedlings in the cab right now (while it's 76F in the room outside the cab). So while it's still in the low 80s, it's hotter today in the house than yesterday so the fan has made an improvement. The plants look happier (less droop) and new growth is present just since this morning.

Thanks for the advice, - any guess on when would be a good time to start 12/12? I was planning on waiting until all the seedlings had their fourth node going. I'm concerned about the height limit I have.

i would wait til they are around 8 inches or when they have around 5 or 6 good sets of nodes

That sounds good to me crazytrain. I'll flip to 12/12 at node 6 or at 8" - whichever happens first.

Just for journal benchmarks, the first five-bladed leaves at node three are growing out. Cotyledons are starting to yellow. Will add first nutrient mix (PBP-Grow) to reservoir @ 1/4 strength this Friday (3/5/2010) and get a good look at the root system at the same time. Having to adjust (lower) pH once every 48 hours to keep it within 5.5-6.5 (about 1 point rise every 48 hrs). Will post pictures tomorrow.

Edit to add: This weekend's project list is to add two more 3" passive intakes, another circulating fan, and temporary lightproofing for the back.

sounds good man. do you have digital ph and ppm meters? if so how much were they? i'm excited to start a hydro grow in my pc case, but i wanna watch a few grows and gotta wait til i move out of parents house lol. i just graduated from college so.. ha

peace buddy

The guy at the store talked me out of buying (surprisingly) an EC/ppm pen. He claimed that with small DWC and bio/organic nutrients it was not as important to fine-tune ppm. That I'd have just as good of result by closely watching the plants as the nutrients are increased while changing the reservoir every two weeks or more often if needed. This isn't really a big deal with such a small reservoir to fill and replace (it takes about 5 min. to do).

I will likely still buy one once I start nutrients... the cheapest I saw at the hydro store was $40.00. But I've seen them on ebay for as little as $15... I'm sure you get what you pay for though when they are that cheap though.

I'm using a $7.00 bottle of General Hydroponics pH drops/kit for pH that will last a couple of grows at least even with daily testing. Digital pH meters will probably run you in the $50-$200+ dollar range. The $7 pH kit I have is accurate enough to give results within a 1/2 point of pH between of 4 and 8.5... the salesman also talked me out of a digital pH meter claiming, "you'll want the pH to slowly fluctuate anyway between a range of 5.5 to 6.5 to maximize nutrient uptake, therefore it's not really necessary to have greater accuracy than a 1/2 point in pH."

I probably won't end up buying a digital pH meter. But we'll see.

And congrats on graduating from college - will be there myself soon.

SableZen said:

The guy at the store talked me out of buying (surprisingly) an EC/ppm pen. He claimed that with small DWC and bio/organic nutrients it was not as important to fine-tune ppm. That I'd have just as good of result by closely watching the plants as the nutrients are increased while changing the reservoir every two weeks or more often if needed. This isn't really a big deal with such a small reservoir to fill and replace (it takes about 5 min. to do).

I will likely still buy one once I start nutrients... the cheapest I saw at the hydro store was $40.00. But I've seen them on ebay for as little as $15... I'm sure you get what you pay for though when they are that cheap though.

I'm using a $7.00 bottle of General Hydroponics pH drops/kit for pH that will last a couple of grows at least even with daily testing. Digital pH meters will probably run you in the $50-$200+ dollar range. The $7 pH kit I have is accurate enough to give results within a 1/2 point of pH between of 4 and 8.5... the salesman also talked me out of a digital pH meter claiming, "you'll want the pH to slowly fluctuate anyway between a range of 5.5 to 6.5 to maximize nutrient uptake, therefore it's not really necessary to have greater accuracy than a 1/2 point in pH."

I probably won't end up buying a digital pH meter. But we'll see.

And congrats on graduating from college - will be there myself soon.

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sweet dude good to know. i was looking into the costs of that stuff after i last posted and thought shit thats alot for suck a small thing lol how often do you check your ph? how long til you graduate? stay in school as long as you can man, finding a job has been freakin tough lol.

peace

I did the whole setup starting without even any tools for $350'ish - and that includes all the endless odds and ends you have to buy (like weather stripping, latches/handles, panda film, etc...). So by the time I harvest just 3oz from it, it's already paid for itself and then some - even if I'm a crappy grower. Besides, it's already paid for itself in entertainment value so no worries even if I don't ever pull a harvest from it at first.

I check reservoir pH at least once a day - but probably not necessary to check it that often. Otherwise I mainly have to pH adjust anytime I add any water or nutrients.

I'm in my last two years of a bachelor's - had been doing the military thing since 1997. Yeah it's a tough job market right now, no doubt. One of the main reasons I'm going back to college along with everyone else.

good deal man. how much of the ph up and down stuff do you have to add to adjust the stuff? never worked with it before. how old are the plants now? pics? ha

peace

Just 2cc's/mL's will change the pH of the reservoir downwards by about a point.

The pH has been holding steady the past 3 days with no adjustment needed other than pH'ing a little water I added to top off the reservoir. Most of the work with pH happens when you add water, nutrients, or additives that have different pH levels being mixed together. Otherwise I just monitor the pH once a day to make sure nothing bad or unexpected is going on. It hasn't been a big deal, just a very slight learning curve at first.

They are somewhere around 2 or 3 weeks of age now. I didn't record the exact date I germinated unfortunately. But they've been in the cab for almost 2 weeks as of today.

Attaching some pics I just took under the lights:

Notes: Stems are starting to thicken up. The runt of the group is growing fast now so probably won't cull it.

Individual pictures for the journal:

awesome dude thanks for the info. deff guna reference this grow when i start my hydro grow...whenever that will be lol

Cool, hopefully you can learn from my mistakes/successes as I go. I'm sure there will be some frustration ahead but so far it's just been enjoyable. Definitely keep me updated with any grows you do!

i'll let ya know when i get started. but since i'm back living with parents i'm not gunna even try to grow. lol they don't know i smoke and i need to keep it that way. but my case is deff stealth enough to get by. but there is always the what if ya know. so may be a few more months til i geta job and move out with the gf. hopefully.

peace