I am running a PVC DWC hybrid type hydro setup, and lately it has been getting very hot in my grow area due to smoking hot weather outside.

It has gotten up to about 86 degrees in the room ambient temp, but the nutes have been cooler, down around 80 or so.

It was suggested to use H2O2 to keep the oxygen going to the roots, so I have been reading up on it and have started adding 20ml to the 55 liter reservoir daily, as well as some epsom salts to try to keep the leaves from yellowing too much as also suggested here.

I'm noticing a definite improvement to my plants, they are growing quite rapidly, and i can see a huge difference from morning to night time in their growth.

I'm just concerned about the heat as I am still getting a bit of leaf curl, kinda "canoeing" like around the edges a bit, but nothing major.

The roots on these 3 week old plants are over 2 feet long already.

I examined the roots and they look pretty good and healthy, and are growing fast (starting to go down my drain tube now!), no noticeable rot or anything, and nothing smells bad, but there is a bit of a "yellowish" tinge to them, is that an indication of bad things to come?
I hope not.

Am I using the appropriate amount of H2O2?

Should I be adding it daily, regardless of if it gets cooler in the grow area or not?

Thanks!!

The dosage of peroxide depends on the strength of it.

I buy the 35% food grade and use it at 0.5ml/L twice a week. This makes a very dilute sol'n of 0.0175% using this calculation.

35% x 0.5ml = X% x 1000ml
17.5 = 1000X
X = 17.5/1000
X = 0.0175%

Close is good enough so you don't have to be dead on exact.

To get the same dilution using a different strength of peroxide you need to know how much peroxide is needed for each litre.

Say you have 29% food grade.

29% x Xml = 0.0175% x 1000ml
29X = 17.5
X = 17.5/29
X = 0.6034ml/L

Or 0.6ml/L of 29% for the same dilution.

A ml is the same as a cc for measuring.

I use it twice a week for maintenance but have gone to 5X that to fight root rot with success.

The 3% or 10% peroxide commonly available from drug stores contains preservatives and is not recommended for continuous use. It's fine for short term to help keep algae down or fight a root infection tho.

With your type of setup your roots will be getting O2 from the air itself so as long as you have lots of bubbles in your rez the O2 should be fine.

At warmer temps it's much easier for nasty things to gain a foothold and can rapidly take over.

The slight discoloration of the roots is normal but watch for any slimy coating and get extra peroxide in there if you see any.

Thanks Labrat,

I actually disconnected the aquarium air pump today and hooked up a medical air pump that makes the reservoir look like it is at a full boil in the middle....lol.

The thing draws 2.5 amps, which sux, so if this isn't gonna give enough O2 to the nutes while in the reservoir I don't know what else I can do.

I put that air pump in an electric coleman cooler thinking it would cool it down and put cold air in the reservoir but instead, the heat it generated just warmed the cooler up, so I actually resorted to floating a couple 1 liter plastic jugs full of frozen water in the reservoir to try to cool the nutes down.

Last time I checked the nutes were 21 degrees C, and the ambient temp is around 26 - 28 degrees C.

It's smokin hot here in NS right now!

So putting 20ml of H2O2 (3% from the drug store)daily in my 55L reservoir for the short term until I can get better quality stuff will be ok for the plants??

Is once a day too much??

How long can i keep adding the drug store stuff before there's an issue do you think??

So how do these plants that were started june 12th look to you? About right for their age, and reasonably healthy considering the circumstances?

I've trimmed off the lower leaves that were heat damaged.

See the leaf curl? I'm pretty sure that's heat related right??

Thanks!!

Labrat, I know you've been growing with DWC for years, but have you ever grown in a recirculating system like NScooknet's, where there are no airstones under the actual roots at 80 degrees?

Reason I ask is I can hit those temps, but my systems all bubble right under the roots. If I have an airstone clog, I'll have problems in the plant above it, despite all the other airstones.

But I don't have the water flowing in my systems, just bubbling.

I know in nature, streams and rivers pick up a lot of dissolved oxygen as they move, crash across rocks, etc.
This is something I've actually wondered about for a while, how much of an effect does the water flowing in a RDWC system actually have on the DO level? (Maybe it actually is possible to have flow rates to the point where as long as you have adequate aeration in the res, you don't need it in the tubes, or a chiller?)


NScooknet, plants look pretty good, btw. The edges of the leaves curling up isn't a big deal, that won't slow their growth or anything.

Thanks guys for taking the time to give me guidance, it has helped me out alot.

This has been a real learning curve for me, not just about growing cannabis, but hydroponics in general.

I've learned alot, but still know that I know very little compared to most people doing this, so thankfully there are people out there like yourselves who are willing to share your experience and mistakes that hopefully keep me from screwing things up too badly.

One question, what is the "ideal" temp or temp range that the hydro nutes should be?

I know over 70 degrees is bad, but what is ideal?

Can it be too cold?

Thanks!

Thanks Labrat, they seem to be coming along nicely thus far, better than I expected my skill level to be able to produce so far for sure, especially in a home made hydro system.

I would probably have more faith in a store bought system that is proven, but hey, what's the fun in that?

Ya aint gonna learn unless you jump in and figure stuff out from scratch.

The nutes are holding at a steady 21 degrees so far, and the TDS is at 700 now, since they seem to be relatively healthy with no more weird leaf things going on (other than the curling from the heat) I figure why push it with the nutes concentration.

So what happens if the nutes are at 21 degrees, but the ambient air temp gets up to 30 degrees, which it has done on really hot days here?

I am going to switch to 12/12 within a week, I just have to staple up some black plastic to close the grow area in to block out light, and before that, I have to put a more adequate air extraction fan in place, right now it's just a wimpy little 4" dryer flex hose with a small fan duct taped to it to suck air out, clearly not enough as my grow area and the back of the house is starting to smell kinda "skunky" at times, uh-oh.

Looks like I really need to get some higher % H2O2 if I want to make sure things don't go wrong, there isn't any mush or anything in the roots, and they are a very slight yellow brown in some areas, but there "is" a bit of a scum forming around the roots floating on the surface of the water.

When I agitate the roots, the scum will float back down into the rez.

After this grow, I'm going to get a few 3 foot long aquarium bubble wands and silicone them to the bottom of each of the PVC tubes, that way I'll be sure to be able to have flow of nutrients from the pump, and also good movement of the nutes around the roots.

Live and learn, hydro 2.0 coming up for the next grow, the challenge is to keep everything going without any problems until harvest time.

BTW, at what time will I start seeing signs of sex in the plants?

My Health Canada plants are not feminized, so unfortunately, some of those beautiful plants I've been nurturing might be on the chopping block eventually.

If I luck out, I won't get any males, but that's probably not reality is it??

Why cant HC at least supply us with proper genetics for a proper yield so that one can actually stick to the 15 plant max??

You "should" be able to grow 30 plants planning on half being male, so that after culling out the males you end up with the allowed amount of plants to go to harvest.

Either that or supply feminized and preferably auto flowering strains for patients that are most likely going to be newbies like myself.

As far as my lighting goes, I have to go strictly with florescent for a number of reasons, and currently, I have six 6500K 4FT tubes going, which I'll be replacing 3 of those tubes with 2700K tubes, and also adding 4 of the 26W 2700K CFL bulbs to it as well.

Hopefully the plants will respond well to that. HPS lights are just not an option right now.

So, what do you think??




The plants on the right are smaller because I didn't get to adding them until over a week after the first plants had sprouted, oops.


These roots are definitely gonna be a problem, gotta put some screen around the drain to keep them from clogging the tubes!

[quote=NScooknet]Thanks Labrat, they seem to be coming along nicely thus far, better than I expected my skill level to be able to produce so far for sure, especially in a home made hydro system.

I would probably have more faith in a store bought system that is proven, but hey, what's the fun in that?

Ya aint gonna learn unless you jump in and figure stuff out from scratch.

Damn right! Screw the store bought stuff! My exhaust fan is out of a microwave that I mounted on a couple of corner brackets and screwed into the wall to fit under a 5"-4" adapter and blow through the existing 4" exhaust pipe. The previous owner had built a cold room downstairs. One of the big reasons I bought this place. It's been working fine for about 7 years now.

It's nice and cool down there so heat isn't an issue unless I'm running 3-400 watters or fire up the 1000W

MH






The nutes are holding at a steady 21 degrees so far, and the TDS is at 700 now, since they seem to be relatively healthy with no more weird leaf things going on (other than the curling from the heat) I figure why push it with the nutes concentration.

So what happens if the nutes are at 21 degrees, but the ambient air temp gets up to 30 degrees, which it has done on really hot days here?

The warmer the air temp the more your plant will transpire so you are better off with lower ppm to prevent nute burn. 30 is only 86F so that's about perfect to promote vigorous growth which is what you want and if you can keep the nutes at 21 or lower you got 'er dialed in!

I am going to switch to 12/12 within a week, I just have to staple up some black plastic to close the grow area in to block out light, and before that, I have to put a more adequate air extraction fan in place, right now it's just a wimpy little 4" dryer flex hose with a small fan duct taped to it to suck air out, clearly not enough as my grow area and the back of the house is starting to smell kinda "skunky" at times, uh-oh.


Once you enclose it you're gonna really have to monitor the temps in there for a few days to see how it goes.

Is odor going to be a problem where you are? Even if your legal and all it's best to run stealth. To many little tweakers out there that could rip you off.

Looks like I really need to get some higher % H2O2 if I want to make sure things don't go wrong, there isn't any mush or anything in the roots, and they are a very slight yellow brown in some areas, but there "is" a bit of a scum forming around the roots floating on the surface of the water.

When I agitate the roots, the scum will float back down into the rez.

You definetly should get some food grade peroxide to get rid of the scum before it turns into something worse. Some big garden centers have it and most if not all hydro stores have it. I got my last liter a couple weeks ago at a garden center in the city for $11.99. Health food stores have it too but usually weaker and twice the price. A liter of 35% will last you a couple of grows.

After this grow, I'm going to get a few 3 foot long aquarium bubble wands and silicone them to the bottom of each of the PVC tubes, that way I'll be sure to be able to have flow of nutrients from the pump, and also good movement of the nutes around the roots.

I've been thinking about that bubbles under the roots thing and I don't think it's a good idea.

Airstones eventually plug up and they will be a bitch for you to clean if you can clean them at all. I usually go through 4 - 12" stones per tub for each grow. 2 running at a time in each tub. I've tried everything to clean them but nothing seems to tune them up. Sulphuric acid just eats them and neither bleach, caustic soda or peroxide did the trick either.

Live and learn, hydro 2.0 coming up for the next grow, the challenge is to keep everything going without any problems until harvest time.

BTW, at what time will I start seeing signs of sex in the plants?

My Health Canada plants are not feminized, so unfortunately, some of those beautiful plants I've been nurturing might be on the chopping block eventually.

If I luck out, I won't get any males, but that's probably not reality is it??

Usually you can tell sex by around 6 or 7 weeks. Tried to find a good link here for early sex identification but no luck. Just look very closely at the junction of the branches and the main stems or where the bud sites

Why cant HC at least supply us with proper genetics for a proper yield so that one can actually stick to the 15 plant max??

You "should" be able to grow 30 plants planning on half being male, so that after culling out the males you end up with the allowed amount of plants to go to harvest.

Either that or supply feminized and preferably auto flowering strains for patients that are most likely going to be newbies like myself.

You seemed to have confused gov't services and logical thought processes. Those two are mutually exclusive.

As far as my lighting goes, I have to go strictly with florescent for a number of reasons, and currently, I have six 6500K 4FT tubes going, which I'll be replacing 3 of those tubes with 2700K tubes, and also adding 4 of the 26W 2700K CFL bulbs to it as well.

Hopefully the plants will respond well to that. HPS lights are just not an option right now.

So, what do you think??

I would stick with the 6500K lights until stretch is over as it will hold the stretch down a bit. Put the cfls in with 2700s to add some red and extra lumens. As the stretch starts you will notice a big spike in feeding that will taper off as the stretch slows. That should be about two weeks then swap in the 2700k 4'ers.

Too bad you couldn't get an HPS for the flowering. I noticed a huge improvement in yield and quality when I got my first 400W HPS. I figure a 600 would be perfect for your setup.

Looking real good so far. I'm curious to see if it's decent pot when it's not all ground up and irradiated like the crap I hear the gov't ships out.

one thing I learned when I kept the MH in for the stretch is my bud sites didn't stretch out to what they could have been and so you'll get smaller buds lengthwise then you would have, just something to think about or consider.