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Bad Ph And Too Much Calmag?

Discussion in 'Cannabis Infirmary' started by MedicalDave, Feb 8, 2019.

  1. Hello farm,

    Having some trouble on my first grow.

    Cliff notes: 3 gal soil pots, watering at wrong ph, gave too much calmag. Will 9 gals tap water @ 6.5ph 75ppm flush save my girls?

    Growing in soil with vermiculite and perlite. 9 week veg, day 6 into flower.
    Been feeding 250-450ppm 5.9 to 6.5 ph for last month.
    I water once a week so the pot dries out. I feed 2 weeks then plain water third week and repeat.

    Things have been pretty good up to this point, although some lower leaves were yellowing on all plants my Canuck white rhino indices was worse off than the others. I thought I was deficient on cal mag so I should add some.

    2 days before flipI went to feed the plants some grow and bloom for flip transition (ended up flipping late) and mistakes were made measuring the calmag, I think I Added too much.

    I added about 30ppm calmag to 10 gals of water with 430ppm of botanicare grow and bloom already in there for total ppm of 460.

    The next day my canuck cookies had some wilted leaves near the top. I thought I overfed and would cut back next time. The day after the blue Hawaiian got hit too same way. Gave all the girls plain 6.5 water, until 1 gal ran out bottom.

    Thought I would let them dry out, then plain water again. Also my 20$ Amazon ph pen has been acting glitchy lately, I’ll replace it and check the calibration.

    5 days later, there’s burn marks coming from the edge onwards and the leaves are drying and curling. But not all the plant is affected, the lower stuff hasn’t been affected. and canuck c99 is showing it too.

    Day 6 I calibrate both meters and the old one was reading 5.8 on the 6.8 calibration solution. So I think I’ve been way off on ph this whole time stressing them out, and now I’ve given them ammonia toxicity trying to correct my false magnesium diagnosis.
    To make it worse my Canuck king tut just got smoked by whatever it is, and it’s not leaves getting burned it’s smaller stems keeling over going limp and real dark. So far the 2 indica doms haven’t shown signs but I’m sure it’s coming.

    So how do I flush out the cal mag, fix my ph and save the girls?
    9 gals of 6.5ph tap water?

    I’m real green and I would appreciate an experienced opinion before I kill them.

    1. Are you growing from seed or clones? Canuck Seeds
    2. How old are your plants? 10 weeks
    3. How tall are your plants? 28”- 40” indicas and sativas
    4. What size containers are they planted in? 3 gal
    5. What is your soil mix? 2 parts bagged cow manure, 2parts bagged potting soil, 1 part perlite, 1 part vermiculite, handful spaghnum moss.
    6. How often do you water and what type of water do you use? Once a week, 75ppm tap water.
    7. What is the pH of your water? 8 after chlorine Evaps, ph down to 5.9 to 6.5 for plants
    8. What kind of fertilizer do you use and what is its NPK ratio? Botanicare grow and bloom
    9. Do you foliar feed or spray your plants with anything? No
    10. What kind of lights do you use and how many watts combined? 1000w mh veg / 1000w hps flower.
    11. How close are your lights to the plants? 28”
    12. What size is your grow space in square feet? 5x4=20
    13. What is the temperature and humidity in your grow space?19-29Celsius.
    14. What is the pH of the soil? Unknown
    15. Have you noticed any insect activity in your grow space? Springtails, 2 fungus gnats on sticky paper. Some small transluscent worms in tray after watering (fungus gnat larva?)- use mosquito dunks and diameter IOU’s earth top dress 1 inch.
    16. How much experience do you have growing? I watched a YouTube video.
  2. Never use plain water to flush a def, only flush with clean nuits, and only flush with water at the end of flowering. 30ml of Calmag is not a lot in 10 gallons. Put some pix up of your plants so it gives other growers a chance to help, it's hard without the plant for evidence.
  3. JWM2

    JWM2 Premium Member Supporter

    You need to check the ph of the soil. Do a search for “slurry soil test” and do that. That will give you the ph of the soil. From there you can make adjustments as needed. However I would advise against major swings. Let them get used to the changes otherwise you’ll stress them out even worse. Find the soil ph and find your tap water ph. Then you’ll have an idea of what to do next.
  4. m8ty


    Get pH drops and toss the cheap pH meter, it also sounds like your soil has enough food for a month or two with out needing to feed anything. Another thing is the soil bugs the cheap soil and manure bags have.
  5. JWM2

    JWM2 Premium Member Supporter

    Yeah over fert sounds very likely. You’ve got the fert and watering schedule backwards. A common technique is water, water, water, fert.
    MedicalDave, 1diesel1 and chemistry like this.
  6. Hey guys thanks for all the reply’s!
    I agree I was probably over fertilizing the plants.

    I took some pictures with a flash light in the room.
    1st is blue Hawaiian, this is how it started out on the plants after I added cal mag.
    2nd is white rhino that I thought was mag deficient.
    3rd is the cookies that was hit first and the hardest. 25% of the plant looks like this.
    4th is the king tut. Instead of burning its turning very dark from the leaf stem to middle leaf and the 3 young tops are going limp.
    Last pic is sample of leaves: two on left are from king tut, one on the right is cookies, and the bottom one is a “normal looking leaf off cookies.
    Highkev and 1diesel1 like this.
  7. Soil slurry test. 1 part top soil by volume, 2 parts ro water at 7.0 and 19ppm / 0.038ec. @ 10celsius.

    Stirred for 5 mins, let sit 30 mins, stirred again and took readings.
    Tested at 7.7ph 102ppm 0.204ec.

    Tested Tap water in garbage can with air stone 8.1 ph 65ppm 0.152ec
    JWM2 likes this.
  8. JWM2

    JWM2 Premium Member Supporter

    Your pH is way too high. You need to get it down to about 6.5. (6.2-6.7) is a good range for soil. Your tap water needs to be adjusted too, thats how your soil got so out of whack. It drifted up after each watering.

    Your soil probably started near 6.5 and drifted up to where its at over time.

    You need to ph adjust your water from here on out. Its very alkaline and will do this if you're not careful.

    When feeding (or watering), mix your ferts then ph the solution to 6.2-6.5 then feed them.

    From here you're gonna have to figure out the best way of adjusting your soils ph. You can do it with watering in a solution ph'd low (5.5 to 6.0) for a while until the ph is in the correct range then once you are in range ph the watering solutions to 6.2-6.5.

    If you have any plants that have been severely affected then you might want to flush the soil with ph'd water to try and save them, otherwise they are going to die and you'll just have to learn from it and move on.
  9. m8ty


    pH drops for the win! Threw my cheap pH pen when I realized it gave me a different reading every time I stick it into the same cup filled with nutrient and water.
  10. m8ty


    Wow! Poor thing, take clones and start over, those plants are cooked! Some times it's just better to toss, learn from it and start over. Take some cuts, root them and next time don't kill them with too many nutrients, and cut that tap water with filtered water like a gallon of tap to a gallon of filter water to thin out all that salinity in your tap.
    MedicalDave likes this.
  11. Looks like a massive potassium deficiency, like the plant is eating it's self. Those uniform yellow leaves have been drawn back by the plant.
    MedicalDave likes this.
  12. The pics show an underwatered and hungry plant in my opinion.

    The leaves in the last pic show calcium, phosphorous and potassium deficiencies.

    Nutrient burn shows at the top or newer leaves first. Lower fans show deficiency of mobile nutrients first.

    If there is lime in your soil mix or oyster shell there is no need to ph most normal tap water.

    Plants do better in my opinion when fed a little dose each watering to runoff to help clear out excess and waste.

    I like to water when a moisture probe reads in the dry section about 2/3 to 3/4 down the pot. Drier is too dry and kills roots and wetter will prohibit uptake and drown roots.
  13. So I did a slurry test on my spare soil mix and it tested at 7.0 100ppm.

    So I’m thinking my water is raising the ph on me.

    I’ve been using ph down every watering and feed for the solution to be 5.9 to 6.5, but it looks like ph is drifting up after I water the plants?

    Should I switch from ph down to vinegar or lemon juice instead?
    Or should I top dress the pots with peat moss or aluminium sulphate?
    SoLowDolo and MIMedGrower like this.
  14. Thanks for all the replys. I appreciate everyone stopping in and giving their opinion.

    I have 2 clones from each plant, and I guess I can always grow more. Next round I’ll have do better amending the soil to account for my alkaline tap water. I thought ph down was enough but apparently not!

    I can’t get the time back I’ve already invested so I would like to finish the grow, get some experience in flower and save the girls if I can.

    This is a personal medical grow which will be made into coconut oil so it doesn’t have to be pretty.

    Would it help the plant to flush with 5.5ph plain tap water until water runs out the bottom then feed with 6.0ph botanicare cns17 -bloom at 250ppm until the run off reads 6.5ph?
    SoLowDolo likes this.

  15. Ph rises as plants eat. It falls in the medium when there are excess nutes.

    100ppm is deficient of everything. My well water is 150 ppm for reference.

    I stand by my post above. Too dry too hungry.

    I suggest running some fresh unadjusted water through the pots until the runoff is clearish then feed a medium dose of a complete balanced fertilizer with micro nutes.

    The botanicare grow is what i use all the way to harvest. My plants take 10-15 ml every watering. Pure blend grow i mean. Says right on the bottle best results feed every watering. I agree but not at their max feed numbers.

    This plant is in a 3 gallon nursery pot. Water only in ocean forest and large perlite mix transplanted up through veg for fresh nutes from fresh soil.

    Then about week 2 starting at 5ml and tapering up each watering (2-3 days) to the plants needs. After peak bloom is in full flowering mode i taper back down ending up at the same 5ml i started with during ripening. Maybe water only once or twice at the end.

    Always watching the leaves to tell me what they need and adjust accordingly.

    Unit541, SoLowDolo, chemistry and 2 others like this.
  16. I quite favour a 3 gallon pot, or rez in DWC, not to big and not so small that the roots suffer the cramps.
  17. jumpincactus

    jumpincactus Premium Member Supporter

    If your water source is indeed suffering from high alkalinity you need to read this.

    Some growers have expressed concern about the "high pH" of their irrigation water and its potential adverse effects on plants. The purpose of this article is to allay some of these concerns by pointing out the difference between "high pH" and "high alkalinity".

    Water Quality: pH and Alkalinity

    Follow link, do your best to understand the difference.

    heres another

    I hope this helps on your next run.
    SoLowDolo and MedicalDave like this.
  18. jumpincactus

    jumpincactus Premium Member Supporter

    heres a snap of a plant tht was watered with water that wasn't due to a high ph but with water that was hard or better stated had high alkalinity. looks like some of your leaves


    I would try to figure out if your water is too alkaline by testing your source water. High alkalinity or too much carbonates will over time wreak havoc in your rootzone. There are test kits you can buy to measure the total alkalinity of your water.

    When total alkalinity as CaCO3 is below 30 mg/L, the water has low buffering capacity. As a result, its pH will readily change depending on what is added to it. When total alkalinity as CaCO3 is above 100 mg/L, the pH of the water is high.

    I use Lamottes as I used to be a live reef tank hobbyist. They are top notch but pricey.

    you want your levels of total alkalinity between 30 MG/l and 100 MG/l
    Last edited: Feb 9, 2019
    MedicalDave likes this.
  19. m8ty


    The plants died when the salinity in the water ruined everything, even if you could save them it would take a month, by then you could have your new plants 30 days in and ready for veg.
    1diesel1 and MedicalDave like this.
  20. m8ty


    Can you get a bag of media with out having to make your own? Usually less than $20 bucks and already has the correct pH, micros and food availability ratios ??
    MedicalDave likes this.