Need help identifying an issue

[Angrytrukker]

Hello fellow forum browsers,

Some of the plants in the grow tent are showing the following signs.

It is day 12 from seed germ.
The grow tent stays on the warmer side, 82-86 deg F.
I've been using the following chart for watering, except I have not been adding the optional CaliMag.
https://www.growweedeasy.com/sites/...s/Drain-to-Waste-Nutrient-Schedule-custom.jpg
My tap water comes out of the faucet at ~120 ppm.
I am using a mars hydro 1200 grow light at 26 inch from the plants 18light/6 dark.

The following picture is another plant from the same tent which has undergone the same watering/ light/ and temps.

If anyone can help me out , I would much appreciate it!
From browsing around online, I think that it is calcium deficiency but I am uncertain so that is why I am here.

Thanks

 

[HigherTheHigh]

That looks like heat burn from maby spraying water? i dont run led but that sounds like its to close, i run a 600w mh at 30".

 

[Scientific]

Hmmm... that is a puzzler, but I'll take a shot.
Ca/Mg deficiency seems like a good guess based on the brown spots on the leaves, but they're young for that, and at 100+ PPM I would guess that you have some calcium carbonate in your water (though not necessarily...), which would argue against that. BTW, Nebula's page on Ca/Mg is very good. You've probably already read it.

I have used Nebula's chart--the same one you're using--successfully and have faith in her advice, so I doubt that't the problem. I suppose a measuring error on your part is something to consider (easy to do--I've done it--just a moment's inattention...)
If it was my grow, I'd add cal/mag, raise the light in case that's an issue, and I would definitely up-pot immediately. I'm certain that you will find that your tap roots are already circling the bottom, which is not good (but I don't think that has anything to do with the symptoms).

Also, although they're not showing signs of overwatering, they look wet. Are you letting the soil dry for a day or two between waterings. "Cannabis doesn't like wet feet."

I wish i had something brilliant and definitive to offer you. Good luck. They really don't look too bad. Do repot soon, though.

 

[Scientific]

That looks like heat burn from maby spraying water? i dont run led but that sounds like its to close, i run a 600w mh at 30".

OK, I like that better than any of my guesses. Maybe a combo of too intense light and too high temp? (Duh, I completely forgot about the 86 degrees--that's significant and way too high).

 

[HigherTheHigh]

Yeah i think thats what it could be, i only ever spray my plants just as my lights go of.

 

[Angrytrukker]

Thanks for the reply!

I think also that the heat is the issue. When I water the plants some gets on the leaves and I try to wipe it off with a paper towel but I think they are still moist and end up burning.

I will try the following:
-Raise the lights a little
-Make sure not to get any water on the leaves
-Repot
-Add the CaliMag to my water
-Water less frequently
-Also gonna try to make a makeshift air cooler with a styrofoam cooler and some ice and lunchbox icepacks so the air goes through that before it goes into the tent.

 

[Scientific]

Thanks for the reply!

I think also that the heat is the issue. When I water the plants some gets on the leaves and I try to wipe it off with a paper towel but I think they are still moist and end up burning.

I will try the following:
-Raise the lights a little
-Make sure not to get any water on the leaves
-Repot
-Add the CaliMag to my water
-Water less frequently
-Also gonna try to make a makeshift air cooler with a styrofoam cooler and some ice and lunchbox icepacks so the air goes through that before it goes into the tent.

That all sounds like an excellent plan to me. Getting that temperature down would make the plants happier. Unless your ambient temp is that high, just ventilating your grow room better can help a lot.

If your humidity is low, blowing a fan over a big pan of water to make a "swamp cooler" will both lower the temp significantly and raise the humidity.

 

[Cultivator]

How often are you watering and are you allowing medium to dry out. I see this alot with new growers who grow in soil. Its likely the start of a root prob due to over watering.

However it could also be calmag def. You are growing under LED and you must supplement with calmag when growing under LED.

 

[Cultivator]

For sure it has nothing to do with wet leaves. Or light being too strong. Those mars hydro leds arent that intense and at 26inch away it should be fine.

As scientific states the plants are a little young for calmag def and id tend to agree normally. However in soil that isnt allowes to dry out and be aerated and with led it can accelerate this issue.