Help! Leaves yellowing, tips brown dying

[Slytiger]

I’ve got some plants with the same symptoms, mid to upper leaves get a yellow edge then the tips turn brown and die. I monitor the PH 5.5 - 6.2 and try to give them CalMag and prescribed nutrients. Not sure what is happening, I’m following all the GWE instructions.

I’m growing in 5-gal coco coir fabric pots
The PH at 5.5 - 6.2
6 weeks into vegetation, grown from clones (*Who’s ya daddy strain)
18/6 light, 80% LED intensity at 30 inches from plants.
81 degrees avg., 60% humidity, 1.0 VPD
Water every 3-4 days with Canna coco A+B nutrients, CalMag

 

[golfnrl]

Hi @Slytiger Welcome Aboard.

Everything appears to be in range. Are those leaves all over the plant or confined to one area? If they are localized I might not worry about it. Do you have air blowing directly on that part of the plant?

 

[Slytiger]

It’s occurring on different plants mostly on the middle to top leaves. Oscillating fans at 5 - 6 speed. 25 min. on, 5 off

 

[golfnrl]

I'm wondering if you don't have a potassium deficiency going on. Could be heat/light stress as well. With an 81 average what is the temp range? Does it get really hot and then cool off? I wouldn't think light stress with your lamp 30" above the canopy. But it could be.

Have you checked out the Plant Problems page on Growweedeasy.com?

How to fix Cannabis Potassium Deficiency (K) Pics & Symptoms

Leaves with a potassium deficiency have yellow, brown, or burnt edges and tips. It may look like nutrient burn, but the leaf margins also turn yellow.

www.growweedeasy.com

 

[Slytiger]

Thanks so much for working with me on this problem. My temps range from 86 - 68 degrees. I have a small A/C ducted into the tent that sort of keeps the temps down, but it maintains an average 80 - 81 degrees.

I had looked at the potassium deficiency page and tried to keep the PH at 5.5 - 6.0 (Nebula says most problems occur with improper PH)

I’ll try to move the lights higher and see what that does.
This is my second set of clones (third grow overall) and I noticed the stems are thinner than in previous grows. I plan to let these go for a few more weeks before switching to flowering mode. Just trying to get a healthy, sturdy base going.

 

[Ckbrew]

I think you are calmag deficient. What kind of coco are u using, did you buffer it before setting up the pots, how much are you using in your nute solution? Why are you watering only every 3-4 days? Coco should never be let to dry out.

 

[Slytiger]

I think you may have given me a clue to my problem. I use Plantonix Coco Bliss but not the pre-buffered version. I had used Ph’d water to expand the 10 lb brick, let it sit for a day, then added Perlite before putting it into the 5 gal pots. Whenever I water, I use Botanicare CalMag plus at 1 tsp / 5mL to a gallon (along with Canna coco A&B) After mixing the nutes I balance the pH to 5.5.

I will get my automatic drip irrigation working again (I hadn’t reconnected the system from my last harvest a week ago) to give the plants a daily watering with the nutrient water.

 

[Slytiger]

If everything goes well I would like to get back to this! It’s my last grow in mid-veg.

 

[Slytiger]

This is how things look currently

 

[Slytiger]

Ok, after a week or so things are all green and back to normal. I was able to soak the coco coir with Canna coco A+B and CalMag and it looks like there wasn’t enough of the CalMag in the soil, so I trimmed off the bad leaves and waited. Once the plants got the proper amount of nutrients, they began growing like they should.

Thanks much for all the help and suggestions, from now on I’ll make sure to get the pre-buffered coco coir.

 

[Allotrope1000]

The experienced forum members noted three things:
- CalMag. In coco/perlite you MUST buffer it.
- Watering. Coco likes to be constantly damp and is near impossible to over water.
- pH. While 5.5 might be a tad bit low, likely not an issue. pH issues always my first check.

Your grow seems to have recovered nicely. Just needed some CalMag and more water/nute solution to distribute it. Good job!