Browning/purpling between veins, and leaves curling. Need help.

Hello everyone. Quite confused here and could do with some advice.

I am currently growing inside a tent, with a 600w HPS light and in coco/perlite 50/50.
I have two plants in the tent, Kosher Tangie and Chemdog.
They are both around 4 1/2 weeks into flowering.
My equipment for measuring temp/humidity, well I don't have anything yet.
I measure PH with indicator, it's around 6.5 and it's been kept consistant.
The temp does fluctuate slightly between day/night.

The Kosher Tangie is fine, had a slight calcium def but that got fixed with a flush and a tiny amount of superthrive. Now it's back on the nutes and looking pretty good.

The Chemdog is where my problem lies.

About a week ago a couple of the main leaves started to fade on the edges, I took this as normal for flowering.

About three days ago I added 5ML/10L of PK boots at 12/14, alongside my normal nutes that it has been loving.

Yesterday I noticed some very dark purple streaks on some of the leaves, curling around the edges and some having brown spots and streaks. So I thought it was P def and gave it anotherfeed with 10ML/10L of PK boost along with and extra 10ML of CAL/MAG (taking it to 20ML/10L).

Today I came home and it is much worse.
So I have just flushed it with PH'ed water and a very small dose of Superthrive.
But I would like some help, as I am new to this.

Photos of leaves attached.

Im growing in basically the same medium , do you have a cal-mag in you normal nutrient feed? you never want to add more nutes when you see any kind of change after introducing a new additive especially more of the one you just introduced,excessive Phosphorus can shut down cal-mag which is vital when growing with coco. You should really get something to measure your temps/humidity it can definitely have an impact on your plants being that your this late into flower for sure something to measure humidity you don't want but mold or rot. Adding beneficial microbes is the best thing I ever did when growing with coco. hope this helps!

Cheers mate, hopefully flushing today with light cal/mag and small amount of superthrive will help clear any lockout of cal/mag if that is the case. Yeah, just waiting for next payday in a week so i can get those things measured and under control.

you defitnely have a heat problem there ,when you make adjustments like that wait a week let the plant recover and then adjust if need be .you got to get you some meters though .

You have a problem with your Heat you can tell by the way the leafs are. Look at the outer edges of the leaves you will see how much the jaggedness on the edges are deep, that means too much heat, When your plants are not getting enough heat you will notice there is a very small jagged spot not as deep, a plant does this to cool down when to much heat is detected, and less when its cooler which is better for your plants, too much heat Good luck

Possibly heat, but also looks like advanced cal/mag deficiency. Hard to say without knowing your temps and where these leaves are on your plant. On top would usually point more toward heat, whereas if they are elsewhere on the plant, they point more toward a deficiency.

that's a heat problem id figure a way to control that soon you don't want your buds to start fox tailing secondly the plant won't produce as well in high heat

Thanks for all of the help, the flushing seems to have stopped the purpling/dying to an extent. I'll keep my room a bit more ventilated by leaving the tent a bit more open from now on. Strange thing is, they have been fine for a few weeks and now struggling with heat ?

gazja420 said:

Thanks for all of the help, the flushing seems to have stopped the purpling/dying to an extent. I'll keep my room a bit more ventilated by leaving the tent a bit more open from now on. Strange thing is, they have been fine for a few weeks and now struggling with heat ?

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Maybe they grew closer to the lights? Count me as one more who thinks it is probably heat related from the pics. Do you have a thermometer in there?

Mountain Chief said:

Maybe they grew closer to the lights? Count me as one more who thinks it is probably heat related from the pics. Do you have a thermometer in there?

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Yeah that's a fair point, I've moved the light a fair bit away from the plants now so hopefully that will help. Get a thermometer in a week when I get paid, I will be getting better out take and in take fans too. Not entirely sure why the leaves have turned purple and then brown between the veins?

The curling up of the leaves is heat stress, or low humidity. The browning in between the veins could be a cal/mag issue or again heat stress. Purpling could be from too low of temps or strain.