Plant leaves browning and getting brittle during flower

**got_milk** · 16-07-20, 08:26 AM

Hello fellow growers.

These 2 plants are part of my first grow, here some details:

Strain: Diesel auto & QuickOne auto
Grow medium: 50/50 mixture of Soil and coco with ~10% perlite
Light : Started them indoor under a set of LED modules ( ~60W, DIY ) Put outdoors in week 6
Pot size: 4.2gal / 16l fabric ( "root pouch" )
Nutrient type and schedule : Early on I used a 7-3-5 fertilizer slowly raising the dosage until I reached the recommended one. Since flowering started I'm using PK 13-14 'enhancer' from Plagron at it's recommended dose with every watering ( too much? )
Watering schedule: Using tap-water, no PH-meter - I think my watering is on point now after some earlier mistakes during veg

Now on to the problem - lately some of the lower fan-leaves developed curling/browning at the tips which are very brittle. I suspect it's either a potassium deficiency or nutrient burn. Maybe one of you pros can pinpoint the problem for me - I gave them pure water yesterday with quite some run off just in case it's nutrient build-up in the soil.

**Jumper114** · 16-07-20, 08:46 AM

Looks like nutrient burn and some heat stress to me. Looks like a fair amount of 'tacoing' going on. As they are outdoors, its not light.

A photo with lights off and a flash would make it easier to be sure.

**got_milk** · 16-07-20, 08:51 AM

Thanks, Jumper. They're outside on the balcony and im getting decent-ish sunlight these days. I'll make a photo with flash tonight and post it.

**Jumper114** · 16-07-20, 08:58 AM

Not sure what you can do other than ease off their feed and see how they behave. I would normally recommend giving them a good flush to ensure no salt build up. However, without a pH meter, and being neither full soil or coco - that could do more harm than good.

In flower they will need a little N as well as PK. I taper down N whilst slowly up PK - whilst maintaining the same EC. I would recommend an EC and PH pen if you continue to use nutrients !

Be aware, PK13-14 is very strong stuff. You want to be 1/4 strength and gently go up. Every feed? Seems excessive for the stage your girls are at..

**got_milk** · 16-07-20, 09:06 AM

I put plain water yesterday with a bit of run off and will do the same for the next watering whilst closely monitoring for new brown spots - let's hope for the best. I'll make some more photos tonight either way, I have 4 more autos that might have gotten a bit too much N as their leaves are noticeably more dark green than the others. ( other than that the leaves look healthy, no clawing )

**got_milk** · 17-07-20, 06:43 AM

Here some more photos taken in the dark with a DSLR + flash.

These are my 4 new family members - 3x Bubble Kush and one Royal Critical. They were just moved outdoor and look healthy besides the leaves being a tad too dark. ( most likely overdid it with the N-dominant fertilizer )

And here a group photo - I built the planter for my 4 initial plants. One tiny HazeBerry is already chopped which leaves 2 more and a Royal Kush which was germinated a few weks later.

**got_milk** · 21-07-20, 09:10 AM

After giving leaving out all nutrients for the last 2 waterings with a bit of run-off it doesn't seem that the issue got worse / spread to other leaves. I guess it could be worse, let's see if the buds continue to develop - as this is my first grow I see it as a learning moment