My plants are dying, help yellow tops & all new growth

1st time coco coir grow. I used perlite in some pots till I ran out, then straight coco in rest. My plants were doing great till week 4. They turned yellow on top and in new growth. I gave it a boost of cal nitrate & Epsom salt with no change in 5 days. I then thoroughly flushed, but no change. Its stopped growing except for the yellowing getting worse. This was the week I was going transplant into growbags that arrived and then next week top & put inside last minute remodeled grow room with 1/2 mh/hps and 1/2 led for comparison. I now have 4000k meds for the next run. Any suggestions? All help is appreciated!

  • Mix of 4-Power Plant, 6-Critical Mass & 5-Train wreck from here(ILGM)
  • Method: 6 Coco Coir+Perlite/ Rest is straight Coco Coir
  • Vessels: From solo cups to whatever modified jugs & pots I had.
    New Grow bags arrived 2 days ago.
  • Avg PH of Rain Water=5.8, Solution=6.16, runoff= 6.1
  • PPM/TDS = 430 avg intro & runoff
  • Indoor
  • 3000k + 660 nm LED w/Samsung lm301b diodes
  • Temps; Day=82°, Night=75°
  • Humidity; Day & Night=50-70%
  • Ventilation system; Fans only so far
  • AC, Humidifier= have on hand but not needed yet
  • Co2; No


Looks like a pretty bad iron deficiency. When I had that issue I hit the plants with a calmag foliar spray (due to the chelated iron in it). Cleared it up pretty quickly. This is a couple days apart

Good deal, that does look better. I’ll sure give it a try. Its my 1st run with coco and everything has went through my head. I had read about nitrogen problems with coco so I went with the nitrate and epsom for the added nitro. Its straight rain water with a EC=0 & occasionally a 1. I did multiple soil test for the npk and everything was checking good. I never thought of iron. Thanks ill start a folier spray this eve when lights are back on. I’ve been using the straight rainwater for my spray. Thanks BobbyDigital! Will follow up in 2-3 days. Happy Growing!

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You really need some green led lights so you can work in the garden at night. Green does not affect the plants photo period.

I would only hit the plants with a foliar spray just before lights out. Water droplets on the plant with the lights on can magnify the light and burn the leaves

It can depending on close the light is. I spray mine lights on or off. But i run my lights at 6 feet and the plants 4 feet below that. They never get hot enough to burn anything.

No doubt, I should have known that. This led is all new for me and I hadn’t heard or read that in my research on them, but makes perfect sense. I have some green led flashlights on my rifles that I can use till I can grab some. I was ready to do it my next opportunity. I’m in panic mode after no growth and watching it get worse for 8 days. My lights have been at 18" for 2 weeks. The hottest it’s gotten is 88°. I put some fans on timers and it stays around 78° on average. I did some burning when I tried the spray with nutes, but none since immediately going to the straight rainwater. I’ve been spraying 2x daily, once at lights on while cool and getting started and again at 15 minutes before lights out. I’ve been so impressed with the newer led’s that I’ve spent a fortune to replace half my room and 2 staging areas that will be moving into in a few days. I’m just waiting for this to clear so I can transplant into the growbags.
Thanks! All advice appreciated! Happy Growing

My last grow i went through same problems. My question for you is your coconut coir pre rinsed before you bought it or if not did you rinse it before use. The problem with alot of it is it comes from coastal areas and is loaded with sea salt and it takes around 4 to 5 weeks for the salts to release enough to really start damaging your plants.
My fix was heavy rinsing of all my pots. First round I did I ran 5 gal ph’d water through 5 gallon planters hoping that was enough but it wasnt. A week later i had to do it again. That finally fixed the issue for me. So you may just need a good rinse. Please consider this before you start adding lots of nutes to your plants that may finish them off.

Thanks Warkat, that’s exactly what I was waiting on someone to say, but hoping it wasn’t as huge a deal as it is. At about 2 weeks too late, I remembered reading that a couple times while researching it. I did not rinse before planting. I just rinsed 2 nights ago at about a 1/2 gallon water per gallon of coco. I’m guessing I better rinse again heavier this time. It seems to always need watering. That’s why I put the freezer bags around them so I could catch and measure my runoff. I was afraid of running over by watering so much. It takes a lot of water to get any runoff started and only overnight to catch 80% of what I put in. My ppm/ec has been near exact what I put in. That’s a big change for me. How often do you water? I’m going into 5 gallon bags as soon as this clears. I’ve been watering every 3 days with no signs of overwatering till my rinse, but as you see it was nothing bad even.

Plantonix Coco Coir Brick, OMRI listed for Organic Use (5 Bricks) 1.4 LBS
It goes on to say “Our coco coir products are organic to be very high quality and very low salt content. Very low level of EC is attained by repeated washing with fresh water.”
Thanks again Warkat!

Preybird1 - It’s been at 18" above plants for 2 weeks. The supplier recommends 18"-24". Had no signs of distress till this. Thanks

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That is the exact brand I’m using now and this is my results on my new grow

A few other pointers.
This is a pretty big temp swing, and a bit on the high side.

Also, I noticed plastic bags around all the containers. You may be overwatering and keeping them too wet. Ideally you want to flood them, and then let them dry almost completely out (ie. Water just before they start dropping).

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Those bags are a big no no the soil has to breath and your suffocating it that way.

Ahh good catch. Yep you have to have air. Sometimes i use plastic pots because it hold moisture longer. A lottttt longer. But now i only use cloth pots.

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Please ignore the temp gauge. I’ve had that thing outside & a lil of everywhere. Also it quit working last week. I meant to take it out. I have 2 digital sensors measuring my temp(1@ plant level & 1@driver area) and 2 on humidity hooked thru wifi. One even has overall air quality. Check, there even still sitting on the 48" heat mat set at 70. Yes I going to remove during this next heavy flush. I had been using.that old temp gauge directly under the lights to try and find any hotspots till it started messing up.
You guys are great and on top of things. I should’ve explained the bags in a lil more detail. I started using them for exact measurement of runoff “overnight” until I got a feel of the coco. Mainly week 2 and again after the flood/rinse 2 days ago. I do not leave them on. I had decided to take pics as I finished the flush. They were temporary only after watering to be on the safe side of overflow in the beginning and for any excess after the flush/rinse. Didn’t want any flooding on electrical items in the floor. It was all threw together quickly while I decided to update my actual room at the last minute. Its a very stable “heat pump controlled” environment. Thanks guys, keep the suggestions coming! I’m grateful for each one!


Beautiful!! Nice job Warkat!! I was well on my way until this. They’re at 4 nodes from starting seed soak on Jan9th. It’s my first time with ILGM and they are by far the strongest seeds I’ve dealt with. I’m now a loyal ILGM customer!! I’m just an old retired and unfortunately disabled guy just getting into experimenting with things indoors. It’s my 4th indoor grow, 1st at this location. It’s completely different than outdoors in 80’s and early 90’s! It was sure fun then, but I really need it now! Lol
Keep me in check if you see anything
Happy Growing

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I to am up there a bit 64 disabled and depend on my meds. This way I know exactly what is used to produce them too.

Good to hear about the bags not staying on