RDWC set-up help needed

ChesPan

Active Member
I have been dabbling a bit with dwc in 5gal buckets, with half way decent results (averaging about 2-3 oz per plant), but I know that I can do better as I have yet to try scrogging. Naturally, to make my life a bit easier if I am gong to scrog then I need an rdwc system. As I was half way into shopping I realized that the design I initially had in mind was flawed. After a bit more research I decided to come here and get help in in planning a new design. Now, a bit about the space that I am working with is a 4x2x7 tent with 600w hid light, 6" exhaust fan (outside the tent), and 6" filter connected to the light. In my original idea I was going to 3 buckets for plants and one for the res, but now I am thinking that storage bins might be the best way to go. I do have a few ideas that I would like to implement into the system such as incorporating a top drip system and using flexible hoses instead of pvc. Also, I am debating whether to make it an undercurrent system or not. So basically the question is if you were building a system from scratch how would you do it? Please keep in mind that I am more of a couch potato than diy guy so any instructions must be simple enough for a 10 year old to complete. Thanks in advance as all helpful suggestions and advice will be greatly appreciated.
 
Naturally, to make my life a bit easier if I am gong to scrog then I need an rdwc system.

That's somewhat debatable. Significantly more potential fail (/leak) points than with a DWC - or even multiple DWCs, IMHO. And, of course, by definition it'll be more complicated. Makes it far more likely that, IF you end up with one diseased plant, you'll have all diseased plants shortly afterward. Forces you to run the same nutrient ratio and strength for all of the plants in the system - which is no problem at all if you are running all clones from the same mother, of course, but it's not uncommon for two or three random strains to have nutritional requirements that vary anywhere from slightly to a great deal. This can even be the case with different phenotypes of the same strain (although generally less extreme).

Yes, pulling a reservoir "out from under" a cannabis plant that has grown into a screen can be a bit of a pain in the @ss. On the other hand, if the plant has grown into the screen a bit, you can often pop the lid, gently lift the root mass out (which IS a PitA for sure), and slide the reservoir out from under it. If you have another reservoir, it's just a swap, which is no problem (again, apart from the whole root mass thing).

Or you can leave the reservoir in place and just transfer the old nutrient solution out. Walk into any real hardware store on the planet and tell them you need a hand transfer pump/siphon for your kerosene heater (et cetera) and they'll sell you one for about two dollars. Or you can spend six bucks for the "deluxe" battery-powered version.

But that's neither here nor there. Everyone is different, and we all have our favored growing methods. When I was doing DWC, I went for big (20+ gallon) single-plant reservoirs, and made sure that I only had one plant per screen, (I liked eight square foot screens, or thereabouts), with a fairly lengthy vegetative phase. That way, when harvest day rolled around, I wasn't in there on my hands and knees trying to figure out how to harvest one plant from a multiple-plant screen; I just sawed through the plant's trunk below the screen, unhooked said screen from the walls, and carried the entire screen (with a helper) into my dining room and plunked it down on the table, where I could work at my own pace sitting in a reasonably comfortable chair. That worked great for me. Others would probably find some reason or other why they didn't like my style (and I theirs, probably, lol). As long as the method you choose works for YOU (or, if not, you at least end up learning things for the next rodeo), that's all that matters.

I do wonder, though:

4x2x7 tent with 600w hid light

How well does that work, having a really bright light in a tent that is so skinny, and twice as wide as it is deep? Do you end up with a really bright spot on the front and back walls, along with shadowed and/or dimmer areas at the other two walls (along the widest dimension)? Or do you use a linear light mover (aka Light Rail) to slowly move your light back and forth across the tent a bit, all day long?

If you DO end up with uneven lighting... as much as I like SCROG, it might not be the best choice for such a setup. With "untethered" plants, you always retain the option of moving them on a daily basis (or twice per day, or three times per day, or...) so that you can ensure each plant receives approximately the same amount of light-energy.

BtW, that size tent would make an excellent one-plant SCROG, using a 20 to 25 gallon Rubbermaid tote as the reservoir. Two, two and a half months vegetative growth (depending on strain choice, of course), and you could end up with a solid bud canopy by harvest. Again, assuming that uneven lighting doesn't become an issue. When you finished, I doubt the plant's root ball would even fit into a five-gallon bucket.

But that's just a thought. Again, whatever works best for you. (Relatively) large plants like that can have their own issues, I suppose. The most significant one I dealt with was the plant consuming seven, even up to 13 gallons of water per day when things got really hot in there. <SHRUGS> Which was usually no big deal for me - but you can do the math, remember to deduct for root space, and see that I couldn't exactly ignore it for more than a day late in the grow. It was not unheard of for me to dump quite a few gallons of water/nutrient into the reservoir before work... and return home to find my air pump and aquarium power head (awesome devices, those!) rattling because the only moisture left in there was a bit of dampness, lol.

Good luck with your grow! I'll be interested to see what kind of setup you end up with (regardless of what form it takes).
 
if you dont want to change your water out you need a chiller, air pump, and hydroguard. I have 4 plants and they suck down 5 gallons and 30 ppms a day (over 35 gallons) which would be hard to manage if you didnt rdwc. . but I've been just topping off for 5 weeks now no slime.

check my system Purps' Perpetual - DIY 800W & 350W LED - 9x6 - COCO/DTW & RDWC
 
Just throwing this out there but you dont HAVE to change the nutrient solutions (unless something goes wrong).

While, technically speaking, it might be true that the gardener does not have to change solution (since there's no actual requirement that the grower do anything, even grow to begin with, lol)...

It helps to prevent or at least minimize salt buildup. Unless you are giving your plant exactly what it needs - but no more - you are always going to have "leftovers." And that could eventually lead to problems. For example (warning: random numbers ahead ;) ), if you are giving a plant 12 PPM of molybdenum per week (whatever actual amount that concentration works out to), but it only consumes 9 PPM (ditto), then you're piling up more Mo each and every time you add nutrients. Of course there's a bit of a gap between "enough" and "too much," but pass that point and you are looking at a toxicity. Charts, threads, web pages, et cetera abound that show us how to spot nutrient toxicities. But even a quick glance at one will show that some toxicities can appear to be deficiencies of other nutrients, either because they mimic the symptoms of same or because they actually cause a lockout.

Some effort and, perhaps, a little luck can allow us to figure such things out, of course. But why take on unnecessary burdens just to save what amounts to a rather small amount of money? My brother likes to say, "Work smarter - not harder."

But if not, a person can usually figure things out, well enough. If they're growing all clones from the same mother, then the plants' nutritional requirements ought to be near enough as makes no differences identical - so it's no big deal.

If, OtOH, the person is growing from seeds, where the possibility of getting multiple phenotypes exists - or different strains, lol, where it's pretty much a given (to one degree or another) and things get just a wee bit more complicated.

If you are doing "fresh pours" every week (or some other time frame that is shorter than "months"), such differences might not even get noticed, assuming that the amounts of each separate element/etc. that are being used each time fall somewhere between the "enough" and "too much" points. You don't really see nutrient buildup even if/when the plants do not consume 100% of what you are giving them each time because you're also removing that excess... each time.

I've done the "no (or, alternatively, very sporadic) reservoir changes," and while it worked, I thought even at the time that my yield was effected. Possibly the taste and even potency. I certainly had more gremlins (issues that weren't especially easy to identify) during those grows.

And, looking back... I cannot really say that I saved much in the way of effort, lol. I guess it comes down to personal choice. Do you want to spend a little time and effort doing regular reservoir changes - or do you want to spend a little (or possibly significantly more than that ;) ) time and effort tracking down odd issues that might not even appear to make sense?

Work smarter, not harder, lol.

If I grow roses just because I like to see a rose once in a while, it's really no big deal whether my rose bush produces a couple now and then or a lot. If it's something that I'm planning on eating for food (or, in this case, consuming for both medicinal and recreational reasons)... then I should probably be at least a little concerned with maximizing my production, given any particular expenditure of time/money/effort/materials.

Another thing that should probably get more mention, IMHO, in regards to DWC / recirculating hydroponics setups is that plants secrete waste products via their root systems. In this, cannabis is not an exception. Over time, this thing can cause pH shifts and even nutrient lockouts. And it becomes another head-scratching gremlin-chasing event when the person starts trying to figure out whether they're giving too much of "X" or not enough of "Y" (neither, lol, their reservoir is just slowly(?) filling up with a bunch of "Z," "W," and "R").
 
While, technically speaking, it might be true that the gardener does not have to change solution (since there's no actual requirement that the grower do anything, even grow to begin with, lol)...

It helps to prevent or at least minimize salt buildup. Unless you are giving your plant exactly what it needs - but no more - you are always going to have "leftovers." And that could eventually lead to problems. For example (warning: random numbers ahead ;) ), if you are giving a plant 12 PPM of molybdenum per week (whatever actual amount that concentration works out to), but it only consumes 9 PPM (ditto), then you're piling up more Mo each and every time you add nutrients. Of course there's a bit of a gap between "enough" and "too much," but pass that point and you are looking at a toxicity. Charts, threads, web pages, et cetera abound that show us how to spot nutrient toxicities. But even a quick glance at one will show that some toxicities can appear to be deficiencies of other nutrients, either because they mimic the symptoms of same or because they actually cause a lockout.

Some effort and, perhaps, a little luck can allow us to figure such things out, of course. But why take on unnecessary burdens just to save what amounts to a rather small amount of money? My brother likes to say, "Work smarter - not harder."

But if not, a person can usually figure things out, well enough. If they're growing all clones from the same mother, then the plants' nutritional requirements ought to be near enough as makes no differences identical - so it's no big deal.

If, OtOH, the person is growing from seeds, where the possibility of getting multiple phenotypes exists - or different strains, lol, where it's pretty much a given (to one degree or another) and things get just a wee bit more complicated.

If you are doing "fresh pours" every week (or some other time frame that is shorter than "months"), such differences might not even get noticed, assuming that the amounts of each separate element/etc. that are being used each time fall somewhere between the "enough" and "too much" points. You don't really see nutrient buildup even if/when the plants do not consume 100% of what you are giving them each time because you're also removing that excess... each time.

I've done the "no (or, alternatively, very sporadic) reservoir changes," and while it worked, I thought even at the time that my yield was effected. Possibly the taste and even potency. I certainly had more gremlins (issues that weren't especially easy to identify) during those grows.

And, looking back... I cannot really say that I saved much in the way of effort, lol. I guess it comes down to personal choice. Do you want to spend a little time and effort doing regular reservoir changes - or do you want to spend a little (or possibly significantly more than that ;) ) time and effort tracking down odd issues that might not even appear to make sense?

Work smarter, not harder, lol.

If I grow roses just because I like to see a rose once in a while, it's really no big deal whether my rose bush produces a couple now and then or a lot. If it's something that I'm planning on eating for food (or, in this case, consuming for both medicinal and recreational reasons)... then I should probably be at least a little concerned with maximizing my production, given any particular expenditure of time/money/effort/materials.

Another thing that should probably get more mention, IMHO, in regards to DWC / recirculating hydroponics setups is that plants secrete waste products via their root systems. In this, cannabis is not an exception. Over time, this thing can cause pH shifts and even nutrient lockouts. And it becomes another head-scratching gremlin-chasing event when the person starts trying to figure out whether they're giving too much of "X" or not enough of "Y" (neither, lol, their reservoir is just slowly(?) filling up with a bunch of "Z," "W," and "R").

Cant argue with ya there, lol well said.
 
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