Continued leaf yellowing & death.

Discussion in 'Sick Plants and Problems' started by TobintheGnome, May 27, 2010.

  1. What type of medium? Soil.
    What brand and type of soil? 2/3 Fox Farms Ocean Forest 1/3 MG Perlite.
    Indoors or outdoors? Indoors.
    What strain? Northern Lights
    How old are the plants? 7 weeks & 4 days. Day 24 of flowering.
    What type of lights and how many watts? 1 600w HPS.
    How far from the lights? 14-16"
    What is your watering frequency and source of water? Tap water allowed to sit for 2 days and adjusted to a pH in the mid 6's. See water/feed schedule below.
    What, how much and when was it fed? NPK? See water/feed schedule below.
    What is the medium/runoff pH and PPM if in hydro? Unknown.
    What are the temps and humidity in the room? 80-83 degrees daytime, 70-72 degrees nighttime. 39% @ 81 degrees.
    What size pots? 5 gallon.
    Any bugs? Look real close. Not that I can see.
    Any other pertinent info? See water feed schedule below.

    Switch to 12/12: 5/4/10.
    No nutes prior to 12/12.
    5/4: Watered.
    5/9: Watered & Fed at 1/4 strength. Tiger Bloom & Big Bloom.
    5/13: Plant #1 flushed with 10 gal pH corrected water.
    5/15: Plant #2 flushed with 10 gal pH corrected water.
    5/18: Watered & Fed at 1/2 strength. Tiger Bloom & Big Bloom.
    5/22: Watered.
    5/25: Watered & Fed. Big Bloom @ 3/4 strength. Tiger Bloom @ 1/2 strength. Grow Big @ 1/4 strength.

    Plants were flushed because of suspected pH issues.

    Lower fan leaves yellowing & dropping.

    Upper fan leaves showing initial yellowing & browning. Starts near tips and moves back.

    Upper fan leaves showing numbers of small brown dots.

    No significant increase in flower/bud size in a week or more.

    See pictures.

    What should I do next?

    a) continue with standard water/feed cycle. Water on Saturday, feed at 1/2 strength the following Wed?
    b) Flush this weekend?
    c) something else?

  2. What is the exact PH of the water going in, and what is the PH of the run off? How are you testing the PH?
  3. The pH of the water going in is 6.4 - 6.6. I'm using an API pH Test Kit to measure pH.
    pH Test Kit - API

    Tap water pH: 6.8-7.

    Using Pro pH Down & General Hydroponics pH Up for pH adjustment.

    I've not tested the run off. I've read conflicting information about the validity of using run off to measure soil pH. I can check at next watering if necessary.

  4. I think you need to get a handle on the pH. My first inclination is that it is running on the low side. The leaves with the spots look like CA to me, which would be locked out at 6.5. The bottom leaves look like N, but that wouldn't worry me too much since you are in flowering mode.

    I use FFOF and my bags seem to be on the low pH side. I water in at 7.2 and measure the run-off at 6.5-6.6. I tested the soil pH and it came back from the lab at 6.5 -ish... So the runoff was fairly accurate, IMO.

  5. You need to stop using that PH test kit. By the time you add nutrients, the color of the water has changed so dramatically, the PH test color chart becomes useless. It looks like you have a PH problem, causing nutrient lock out.

    Checking the run off is the best way to know, for sure, what the PH of your soil is. Pour slowly and let the water go fully through the soil. You don't want to have it drain down the side and out the drainage holes, you won't get a very accurate reading.

    Good luck.
  6. That's a calcium def mate, I get that all the time with coco LOL Calcium gets used up heavily during flowering, I normally see it starting at 2 or 3 weeks into flower. Looks like a little mag def too (they go hand-in-hand most times).

    Most likely it's low ph, either your water is low, or you have nutrient buildup in your soil (making the ph low), or both!

    Runoff ph is your essential friend here. The conflict you read about are most likely the sticklers who like to harass people and say it's not an 'exact' measurement. And they are right, it's not, but it's very valid for what we need here, and accurate enough to adjust and get you back on track.

    Getting your ph straight is priority, adding more calcium/magnesium will make the problem worse if your ph is too low (toxicity issues...).

    You did good with the flush, I think you need to raise your water ph a bit (runoff reading will confirm). This calcium issue is a major pain because it will continue to progress for a bit after it's fixed. The spotting will stop eventually, but you will lose a lot of leaves. Stay strong man!

    Calcium & mag lock out below 6.5 (talking soil ph, not water in soil's case)

  7. Thank you for the feedback gentlemen. :)

    I'll water my babies this Saturday and get a reading on the runoff pH.

    Assuming pH is the problem, should I do a 2nd flush? Or just bring the water pH up on future waterings/feedings?
  8. #10 Antigen, May 28, 2010
    Last edited by a moderator: May 28, 2010
    You could do another flush, and use 15 gallons if possible. I know it's a lot, but sometimes you need that much to push all those acid salts down to the bottom of the pot and out the drainholes. Most of that crap likes to sit near the top so you need to add lots of water to make sure it all flushes out.

    You can also add 1/2 strength nutes to the last gallon you flush with, since flushing will also remove nutrients.
  9. 15 gallon flush is underway. Plant #1 is finishing up its draining. Plant #2 to begin shortly.
  10. Now that I've completed the flush, how long before I see any sort of results? What should I look for? Will the spots go away? Or just stop their expansion?
  11. Also, I'd been hoping to start adding Molasses next week. Is it added to every watering or just the feedings? How much per gallon?
  12. its probably the MG perilite you have in there. I've had the same situation and once I switched them to straight FF Ocean forest it went a way. Besides ff already has perlite so why add more?
  13. You can probably expect the damage to continue a little more even though you have corrected the problem. The damaged leaves will not recover and will probably get a little worse. As long as your new growth is not affected and the problem does not get a LOT worse then you should be OK.

    And I don't know about the molassess, I have never used it.
  14. ^^ I agree with all Antigen has said here. Calcium is such an irritating def IMO because it's so delayed in stopping. But as long as the runoff ph is 6.5 or higher, the plant will be be fine even though it'll look like it's not. The damaged leaves will continue to yellow, brown, & die - just watch the new growth.

    And I think it's good thing you added perlite, flushing can be a long and miserable ordeal with soil that doesn't have much. It has a ton of benefits and does not cause calcium defs that I'm aware of, in fact MG perlite is coated with nutrients which I've always found a plus.

    Molasses is a good thing, especially if you have organics involved (and you do with FFOF...). Molasses is food for the beneficial bacteria that turn organic matter into food, and it supplies a few nutrients as well. 1 tbsp/gal usually works fine, once a week is plenty.

    Hope this helps!

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