Edges of leaves burning/dying

[JP1]

Problem: edges of leaves changing. Getting worse going into flower

Medium/grow method: coco autofeed dtw

Feed: and supplements used: Athena liquid nutes, calmag, recharge, yucca 500-580ppm. Just switched to flowering nutes this week

water source: well water 70ppm

Strain/age: multiple strains, all autos, 8/10 plants showing same issue. About 60 days old

light used: led. Mars fc6500

Climate: indoor tent 75* 60%rh

Additional info: grow journal

https://www.autoflower.org/threads/jp1-way-over-my-head.88679/

 

[jam005]

I get this. i could be 1million % wrong but i get this when i forget to ph my bloom feeds when using Explode a bloom additive, or im just doing it wrong. i dilute my feed further and take off all damaged leaves. i get leaf curling through light damage as well as i use a few small lights. i would calibrate my ph pen which i do whenever i have these problems. just to be safe and have a look at the bloom feed again. if its only some plants it could be a reaction to the new bloom food. your tent looks great. i love your tent floor.

 

[JP1]

Definitely not pH. Gets checked every day and I check calibration weekly

 

[MIAutomatic]

I bet you are getting salt buildup in the medium. I know there is a lot of advise that suggests coco is a good medium for drip fertigation, but it really does much better with flood style watering IMO. Even when feeding at low levels with drip I always started to get burn on my leaves. Coco really needs to have its “reservoir” refreshed at least daily during vigorous growth. The reservoir in this case is the water your pot holds. I think with drip in coco the liquid exchange does not happen quickly enough to make sure the medium is getting properly refreshed with new nutrient solution. Think of it as running a DWC but just constantly topping up the reservoir. It works fine for a while, but eventually you will run into balance issues.

I suggest you hand water one pot till you get 20% runoff and check it. I bet the runoff EC from a vigorous hand watering will produce runoff with much higher EC than you nutrient solution.

Good luck!

 

[JP1]

I clean and refresh the rez weekly. They get watered 6x/day to runoff. I also weekly top water with a quart of fresh feed and yucca. I was getting a lot of salt build up on the bags and added slf100 to the feed starting a couple weeks ago and the salt has basically disappeared from the bags

 

[DCLXVI]

Yep, I read through your thread and any little bit I could come up with, you already had covered. I am at a loss. Hopefully someone much smarter and experienced comes along.

EDIT: just an idea but; maybe try watering less frequently with more volume for a slight wet/dry cycle? See if it improves?

 

[MIAutomatic]

EDIT: just an idea but; maybe try watering less frequently with more volume for a slight wet/dry cycle? See if it improves?

This is exactly the approach I would take.

 

[JP1]

I've actually been upping the watering lately since they were drinking more. When I stop getting runoff from a couple I usually up it. They started not producing runoff about 2 weeks ago so they went from 24 to 32oz/day. Upped it again last weekend. They're currently getting about 48oz of feeding per day each with runoff

 

[DCLXVI]

What is the ppm of input and runoff?

 

[JP1]

540 going in. I'm check the output after work