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Thread: Help identifying ongoing problems

  1. #1

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    Default Help identifying ongoing problems

    Hello people! I'm a noob growing my 2nd plant (1st time indoors), and I'm having some problems which I fail to identify. I would appreciate any tips, advice or opinions.

    TLDR: https://imgur.com/a/C9WFHQm (scroll down for more pics)

    34 days ago I planted an autoflower seed (silver haze auto) in generic gardening soil I had laying around, which I mixed with around 10% lava rock which I use for my succulents (I thought it would help with for aeration). I sterilized the mix in the oven as I had some problems with fungus growing other types of plants in the past.

    Mistake 1: I over saturated the soil with water before adding the seed as I didn't know any better at the time. The seed sprouted 3 days later, so the plant is 31 days old now.

    At day 9, I saw the first problem: leafs were curling inwards and seemed very dry (https://i.imgur.com/YMeodYf.jpg). After asking around for advice, I believe this was due to a combination of factors: lights too close (I use LEDs, at the time I was using 2 x 13 W 1500 lumen 2700k phillips bulbs, as in this video https://www.youtube.com/watch?v=XnIzB_8knLU,at 10cm from the plant) + low rh (~40%) + very strong ventilation. I turned off the ventilation, lifted the lights, got a humidifier and everything got a bit better over the next days (here is the plant at day 11: https://i.imgur.com/wBsIS5g.jpg).

    At day 13, the plant started showing yellow / brownish tips on the branches, which was surprising as I hadn't started yet feeding. I got a TDS meter and measured my tap water, turns out it's very hard, around 400 ppm, with a ph of ~8. From this point I switched to distilled water, to which I add 1 ml of plant magic calmag per liter, which brings the ppm at ~200.

    Mistake 2: I went overboard with the humidifier, leaving it on all the time for days, to the point that the leaves were constantly wet. Around day 16, this (or at least I think this is the reason) caused the new growth to claw and the lower leaves to show rapidly yellowing and browning, showing deficiencies. From what I read, too much humidity in the air prevents the water flow from the roots up into the plant, so no nutrients are available, that's my reasoning for concluding yellowing + browning were deficiencies.

    I removed the humidifier, got a new rh probe as the old one was showing 60% even though the leaves were soaked and kept going. Even though the plant looked bad and it never fully recovered, it got better and kept growing.

    I started feeding at day 21 with 1 ml of 7-3-6 fertilizer per liter of distilled water, in addition to the 1ml of calmag, bringing the total ppm at ~350.

    I water by weighing the pot every day: I waited until what I thought was completely dry, wrote down the weight, and wait until it reaches that again to water. Typically for me that is ~1.9kg dry, then I water until I have decent run-off (~1l of water, pot is 6l), I wait a few minutes, then weigh again and it's typically ~2.3kg. I used to water once a week in weeks 2 and 3, lately I'm watering ~ every 3 days. I also noticed that when the pot is ~1.9kg the plant droops a lot and it takes it ~10-12h after watering to perk its leaves back to normal. I also have a 3 way meter measuring light / soil ph / soil moisture which I use to double check the moisture level before watering, and it's almost all the way to dry. I am adding all these details because to me the symptoms look like overwatering and I am very careful not to do it, but it's possible I still do.

    I also measure the run off ph, which is 6.5, the same as the feed, and the TDS, which is ~400 ppm, a bit more than the 350 ppm feed. From what I read, this could indicate some build-up in the soil.

    Light schedule is 20 / 4, I grow in a PC case which I converted and use 6 led bulbs like in the video above which should give ~750 par. The bottom of the case is raised and has holes for air getting in, and there are 2 exhaust fans on the "roof" of the case (which has holes as well) for getting the hot air out. The temperature stays at ~27.5 - 28 C while the lights are on, and drops to 21-22 when they are off. The humidity stays at ~45%, goes up to 65% for a few hours after I water.

    The main problems that I still see:
    • new growth continues to have yellow tips, and has done that since week 2
    • the older leaves keep dying (yellowing, then browning), and it seems to keep moving up (I remove the leaves once they are fully yellow)


    Pictures of the symptoms: https://imgur.com/a/C9WFHQm (scroll down for more pics)

    Thanks very much for reading this far, and for any help you might offer!
    If I forgot any details, let me know!

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  3. #2

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    I think you had everything going correct right up until the point you went to distilled water and calmag, all calcium and magnesium mixes have significant nitrogen and other minerals that you don't need in such high quantities. A better solution would be to use distilled water to reduce your tap water by 50% or maybe 60 or 70% if that makes you feel better.

    I would go ahead and flush the plant with a mixture of distilled water and tap water, about three times what the pot can normally hold. Then come back with a light feed and work from there.

    You've actually done quite well figuring things out and I applaud the early part of the grow where you figured out you had low humidity, low lights and too high of fan speed. I think you were spot on there.

    If you want to stick with distilled water and calcium and magnesium supplementation then put 1 mil of calcium magnesium in 4 liters of water and see how it goes. Remember to get plenty of runoff cuz that stuff will build up in your soil.



    J

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  5. #3

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    Thank you very much for your answer! Indeed the calmag solution is very high in nitrogen (8%), so I will back that off and see how it goes.

    I will follow your advice and flush, then stick to regular tap water diluted with distilled water. I pulled up the water analysis of my city, it should be around 3 ppm No3, 120 ppm Ca 2+, 10 Mg 2+, 130 SO4, 60 ppm Cl and 40 ppm Na. So very rich in calcium and sulfate with little magnesium in comparison. Do you think this imbalance could cause issues?

    Last questions: would it be possible that I still overwater, i.e. would overwatering symptoms look similar? Or, even though I know it's very unlikely with autoflowers, that I underfeed?

    P.S. sorry for breaking the rules, and creating a new account. The original one got banned because I spammed to be able to post links (even though I don't think I did, I just wrote thank you messages for the guides I've been reading as a lurker, but I understand how it looks). Just want to apologize if I offended anyone, and thank you for the wonderful content created by this community.

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  7. #4

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    Over-watering can have some similar symptoms, but it becomes real obvious very fast and it can be severe. once over watering advances a little bit your new growth will be very droopy and almost look fuzzy or kind of like velure in texture it's kind of strange to describe. I don't think that's an issue for you right now.

    You probably will end up magnesium deficient at some time and the solution to that is an occasional foliar application of magnesium sulfate, magnesium sulfate is epsom salts with no smelly stuff or additives.



    J


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  9. #5

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    Banned means just that... banned!
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