Plant died in 3 days, yikes

[The Germinator]

It's simple actually. Give the plant what it needs and don't need and it'll grow. You did something wrong. Not enough air or too hot of water or too hot of air temp or too much nutes or ph was off ect. Back to the basics.

 

[TorturedSoul]

Could a few days of over 90 degrees take the plants out?

Yeah, if you weren't supplying sufficient amounts of DO to the reservoir and/or it was comparable in temperature to bath water. Otherwise, highly unlikely, IMHO.

When a plant - and cannabis is no exception here - has sufficient oxygen levels in the reservoir and sufficient airflow above, the process of transpiration will allow it to survive low triple-digit (F) temperatures. It won't be a real productive time for it (understatement), and if it's a regular thing you can expect airy buds at harvest time, but it won't kill it.

What I consider to be sufficient levels of DO in the solution is "a bit" higher than many seem to, lol. (I used to joke that it'd take a mouse a half hour to drown.) So bear that in mind. Also, if you use aquarium air pumps as your aeration devices, remember that those things heat the air they're pumping into your reservoir. Not greatly so, true... But hop in your car, roll the windows up, and turn your heater on low. Hot yet, lol? Now stay in there for days and never turn that heater off. Dead yet ? Yeah, it's like that for the plants, too.

When you're pushing the upper range of temperature, you'll want to maximize the amount of light-energy you're giving the plant(s), too. Plants @ 100°F under 62½ watts per ft.² of HPS light are going to be a lot healthier than ones @ 100°F under 32 watts per ft.² of CFL light. There's a relationship. This is also reflected by the fact that plants can process more light-energy at higher temperatures (to a point, of course). It's actually a three-way relationship, with CO₂ level as the third factor. But adequate fresh air should have ensured that the level of CO₂ didn't drop enough to have killed your plants.

Been my experience that a "too warm" but highly-oxygenated reservoir is a healthier environment than one that's of reasonable temperature but isn't sufficiently oxygenated. Of course, there's heat and then there's heat, lol; if you're making soup, it doesn't really matter.

When you get into conditions like this - and assuming that you didn't have a [FAIL] on the whole oxygenation thing, of course - what often happens is "little problems" become BIG ones, and they can end up killing plants. It's like... Well, you'll probably survive having to work ten hours on a hot day better if you haven't just received a beating first. Or something. Less room for error.

Are you regularly calibrating your pH and EC meters? An out-of-calibration meter is worse than no meter at all.

 

[spysmasherr]

All great points. My well water PH has always been spot on for gardening. Under 7.0 always, usually around 6.4 ish. A DO use an aquarium air pump. Did not know they make "hot" air which combined with the heat wave that hit could've been the tilting point. I have calibrated my PH meter (with solution) but not sure if I did my EC meter, don't think so. What do I use to calibrate the EC meter and what is a good choice for oxygen pump that won't heat the air? This growth didn't see and note burn up to their dyeing off days. Thanks

spy

 

[flashmp3]

6.4 may have been too high for hydro! Most of the time death is linked to bad ph or too hot temps

 

[Mayne]

tuff lose man,

DWC is supposed to be 65-69F res, and 5.8 PH, not 6.5.

also, think about this, If your pump is in your tent, the air your hitting your res with, is being HEATED by the same air temp in your tent.

Ive done DWC, and it was the worst mistake and waist of time and money on the BS, in my case anyways. PH Perfect saved my enthusiasm, lol.

 

[spysmasherr]

I get what is being said. As a senior gardener at 57, I've actually been gardening since high school. Regular gardening that is. I have a big vegetable today garden and made my own Raspberry farm. I make awesome jam!!! Good for the munchies. I used to take care of country homes for rich people in NYC when in high school. That is how I got into gardening. One home had an older son who was a true marijuana enthusiast, travelled the world seeking big bud . He happened to leave a 1/4 lb of Yellow Acapulco Gold gold. It was my bailout when I didn't have weed. In the early 80"s I grew some serious sense, one garden purple hairs, one garden orange. That was in dirt. The hydro is new to me. So I am learning. The thing my plants were actually doing great and then. BOOM. I've experienced root rot but that comes on a little slower. I just hope to avoid it from happening again. Funny my 1st grow last year in hydro was good. Had some nice Afghan Skunk and Topcat plants. No real problems. Anyway that's my story. Gonna start one new DWC plant pretty soon. Will make a few changes and take it from there.

spy

 

[The Germinator]

Unless you're using a water chiller then your water gets as hot as the room if not hotter. Even using hydrogaurd or z7 I'd still try and keep water under 75. The cooler the better. At high temps there's not as much oxygen. There's some good advice above.
Use good calibrated meters. Ph and Ec
Keep temps within range. Water and air.
Good airflow. Less is usually more of anything.

 

[Virgin Ground]

The warmer the water, the less oxygen it holds. As the temp goes up you must increase surface turbulence in order to oxygenate the water. Air pumps do not add oxygen directly to the water. Oxygen is raised through gas exchange at the waters surface brought about by turbulence. I do not run hydro. I do however keep aquatic plants and fish. Same theory applies. I guess should go educate myself on hydro now though. Do plants take any oxygen from the water?

 

[spysmasherr]

My thought was the roots get more oxygen in the hydro vs soil setup...thus bigger and better roots leading to more uptake to help the plants produce more product.

spy

 

[Lazarus13]

That pic made me sad! I grew in dwc for about 2 years and had decent success but summertime battles with rez temps and lugging water up steps twice a week were wearing me out. I switched to perlite hempy and can say without a doubt im glad i did. Almost the same growth rate as dwc with none of the same worries. Its been easy peasy. If you're going to continue in dwc a chiller will be your besty. I also used to sit my air pumps on my a/c register to cool both the unit and the air coming out of it.
Good luck on your next go.

 

[TorturedSoul]

6.4 may have been too high for hydro! Most of the time death is linked to bad ph or too hot temps

I'd expect the pH to drop when he adds nutrients to it. In the flowering phase, especially (phosphorous).

If your pump is in your tent, the air your hitting your res with, is being HEATED by the same air temp in your tent.

Yep, should ideally be outside of the grow space (and higher than the reservoir, to prevent any possibility of coming home one night and seeing that the pump shat itself and allowed your reservoir to siphon dry).

Ive done DWC, and it was the worst mistake and waist of time and money on the BS, in my case anyways.

I've always seemed to do better in DWC than soil and soiless. Just can't seem to really get into the latter (although I'll still use it from time to time). We all have our own personal "best methods."

I get what is being said. As a senior gardener at 57, I've actually been gardening since high school. Regular gardening that is. I have a big vegetable today garden

Growing cannabis is just like growing anything else (and easier than some things). Just need to know the pH sweet spot and the ratios of nutrients that it prefers, on average (will be some variance from strain to strain). Deficiencies and toxicities will exhibit the same symptoms, regardless of the type of plant (more or less), so if you can tell what's wrong with your tomato plant, you can tell what's wrong with your cannabis plant. Except you shouldn't ever see blossom end rot (but cannabis also loves calcium).

The hydro is new to me.

Best pH shifts downward a bit. Nothing is there beforehand in your media, it's all supplied via your nutrient solution. Keep the dissolved oxygen level of the solution as high as possible. No soil means no buffer - screw-ups show fast (almost immediately) - but fixes do, too... If you do 43 different things, over time, and go into your grow room one morning and find your plant figuratively laying in a corner, crying, lol, it's most likely due to the last thing that you did, which kind of cuts down on the guesswork. Don't drop an extension cord into your reservoir . Not enough DO in your DWC is comparable to being constantly waterlogged in soil. Don't put your aeration devices on your lighting timer, lol. If you've got a 23-gallon reservoir - but you're growing a <BLEEPING> tree, and you decide that, "Ah, it'll be okay if I don't bother to top of the reservoir before I leave for work," don't be terribly surprised if you come home late that evening and hear your various aeration devices rattling because the plant has transpired 13+ gallons of water while you were gone and there's just a damp spot around the root mass. Keep your meters in calibration. The higher the DO level, the more efficient the plant is at using nutrients (therefore, you may well find yourself not having to use as much). Leave the "organics" for other growing methods, that way you won't end up growing other things than just cannabis in your reservoir - plus, you can supplement with H₂O₂, both to prevent "nasties" and to give an oxygen boost when it (quickly) decomposes. By all means, use air pumps and air stones. But also consider adding one of these to your reservoir:

Aquarium Powerhead

• TorturedSoul
• May 6, 2010

Inexpensive aquarium powerheads circulate while injecting air.

Oh, and relax . Have fun.

Air pumps do not add oxygen directly to the water. Oxygen is raised through gas exchange at the waters surface brought about by turbulence.

YES!

Do plants take any oxygen from the water?

That's how they get it, via their root system.

My thought was the roots get more oxygen in the hydro vs soil setup...thus bigger and better roots leading to more uptake to help the plants produce more product.

Yes, that plus one generally feeds the plant directly (as opposed to feeding the microbial life and having that excrete nutrients in a form that the plant can actually use).