Light Burn Heat Stress Issues

Discussion in 'Sick Plants and Problems' started by waffle house, Oct 8, 2014.

  1. #1 waffle house, Oct 8, 2014
    Last edited by a moderator: Oct 10, 2014
    My plants have light burn and heat stress, one of them is pretty bad with yellow covering maybe 20% of it. I let them veg too long (1.5 ft on avg.) and they grew a lot taller than expected. My lights quickly got maxed out and my heat in my room went up. To make up for this I added co2 with a controller, but I am using a room not a tent. Doesn't look like the light burn is progressing but I still see heat stress. What confuses me is I thought with co2 I could run hotter in my room but I am still seeing stress when temps get about 85+ Would not using a tent with my co2 be wasting all the co2? I am running a 2 hose portable a/c in there and a few fans running with no exhaust. Any advice for anything is appreciated thanks. If yall need pics i can provide.
    I am running DWC in 5 gal black buckets, using hydroton as the medium. The set-up is indoors, in a room not in a tent. I think they are a mix of indica/sativa because they went from 1.5 ft in veg to 4.5 ft in flower.
    They are 5 weeks into flowering.
    (2) 600w (1) 1000w on them in flower they are approx. 1.5 ft from light (maxed out here). I am running HID lights and currently running HPS lights on them for flower.
    I change the resevior out once a week and use tap water with chlorine conditioner. I am using Adv. Nutes Coni A&B + some supplements. I fed them 14-1500 ppm with the avg. ph at 5.8.
    I am running a 20lb co2 tank with regulator and co2 controller set at 1500 ppm. My temps range from 75-80 lights off and 80-90 lights on depending on how hot/cold outside.

  2. No pics no proof
  3. I've got my lights raised up higher, and my ambient temps are starting to drop with the weather. Plants are recovering and looking a lot better. Just wondering why my plants are getting so stressed during the heat even though I'm running co2, makes me think I'm doing it wrong...
  4. Maybe this will help, observe below:
    Many growers do not know that water's pH will fluctuate on its own depending on the surrounding environment. Reverse osmosis and freshly distilled water start with a relatively neutral pH (around 7.0), but the pH of this water will actually lower when this water is exposed to air. This is because the water absorbs carbon dioxide from the surrounding air. This fluctuation can be intensified in growrooms that supplement CO2, which is one of the reasons why so many indoor horticulturalists who supplement CO2 experience difficulty balancing their pH. In a CO2-enriched environment, it is not uncommon for neutral water to drop to a pH of 5.0 within a few hours. One way to minimize this effect is to remove the reservoir from the growing environment so it will not be exposed to high levels of CO2. Hydroponic systems where the nutrient solution makes minimal contact with the growing environment are less affected by the CO2-caused pH-lowering phenomenon.
    Tap water is even worse in terms of pH instability because it is chock full of elements that will affect pH. Calcium and magnesium, which are known to cause pH instabilities, are probably the largest contributors to pH fluctuations in tap water. This is one of the reasons why so many hydroponic growers use filtration devices to remove excessive amounts of these elements found in tap water. Growers with hard water often experience constant problems with pH stabilization due to the high concentration of calcium and magnesium.
    The nutrients used by hydroponic growers also have a direct influence on the solution's pH. In fact, the higher the concentration (measured in parts per million), the greater the influence nutrients have over the pH of the solution. Nutrients affect pH in a few different ways. First, as the chemical compounds are broken down by enzymes or microorganisms, some are absorbed by the plant, but the remaining portion is left in the solution to contribute to the pH. For example, when a chemical compound is broken down for nutrient absorption and produces leftover molecules that are alkaline, the pH of the solution will rise (become more alkaline).
    It's not just the remaining molecules and their pH that affect the solution's overall pH, however. The plants themselves, as they absorb nutrient ions, give off ions in return. For example, when a plant absorbs potassium ions, it gives off hydrogen ions in return. Hydrogen ions are acidic and result in a lowering of the pH. On the other hand, a plant gives off hydroxyl ions when it absorbs nitrogen ions, resulting in a rise of pH.
    Growing medium
    Last, but not least, is the medium. Although most growing mediums are stable, their chemical composition still affects the pH of the nutrient solution. There are countless chemical and biochemical processes happening in and around the medium, all of which affect the pH of the nutrient solution. Hydroponic gardening has an extremely high absorption rate and, teamed with a comparably high concentration of nutrients, the medium is ultra-sensitive to these chemical and biochemical processes. In nature, soil acts as a large-volume natural pH stabilizer. The pH stabilizer in hydroponic gardens is the solution itself, which is extremely weak in terms of being an effective buffer. As the concentration of a nutrient solution changes due to absorption by the plant or evaporation of the water, the pH will also change.
    Hydroponic gardening speeds up virtually every biological process and, in turn, can accelerate pH fluctuations. In order to maintain a pH “sweet spot,” growers must gain a heightened understanding of all the contributing factors that affect the pH of the nutrient solution.
  5. I don't really have any issues with Ph I use a digital Ph meter (and tds meter), I usually only have to adjust it initially when I add nutes and usually just once before the next water change.
  6. Thought maybe it was the CO2 spiking your ph.
  7. Here's some pics. Maybe we can help each other.

    Attached Files:

  8. simple overfertilization
    when temp rise water evaporate and you can't feed every time watering, give only water and feed with nut once a week

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