Help crispy leaves

[Rompson]

Hey peeps, first time grower and poster,
So I am going to add some photos to this post to see if anyone can help me with what's going on here. Here's a bit of info

Growing a couple of white widow in coco perlite mix 70/30. Am using a coco specific nutrient that's says it is buffered with cal mag currently have never gone more than a tad over half the nutrient recommendations which comes out at a ppm of about 1300 with my tap water being 350 of that. Am using a resivior run to waste system which feeds water nutrient mix till run off once everyday. Ph 5.8 through veg and 6.0 in flower. Photos are taken about 4 weeks into flower.

Anyway as can see from the photos the leaves begin to brown from the edges in. Sometimes looking someone what spotty. They go dry and crusty and tend to curl down or to one side. At first I thought nutrient burn and lowered the amounts of nutrients drastically but this had little effect. I also flush every two weeks with ph balanced plain water. My run off readings are same ppm as going in with ph run of slightly higher 6.2. This all started just before the flip about 5 week ago and has got worse. I have now added cal mag at 1ml per litre to resivior for the last 2 week since a lot of research I had done pointed in that direction. Also i dont think it's light burn since lights are always around 2 feet from canopy . Can anyone help me with what they think this might be. Need anymore info just let me know. Appreciate any help I can get.

Cheers

 

[Old Salt]

to the form...

Light burn was my first guess. What light are you using, HPS?
Heat stress is next on my list. Is your hand comfortable at the canopy level?
What nutrients are you using? Chances are one of our members is using the same brand.

I grow in coco/perlite using General Hydroponics' Flora Trio and supplements at 30% label strength. I feed my plants the nutrient solution twice per day, 20 min after the lights come on, and 1hr 40 min before lights out until I get 10% run off. This is automated. I never give them water only.

In my opinion, the PPM and pH of the run off are not important. The concentration and pH of the nutrient solution you use is important. I don't check the PPM of my nutrient solution, prefering to go by the concentration of nutrients I add. I do adjust the pH. At this stage of growth I set it to 6.2.

 

[MickFoster]

I'm no expert at diagnosing plant problems but I think it's nute burn - I would cut back on the nutes. Good luck.

 

[Rompson]

Hey man cheers for the feedback. I was running 600w how but recently changed it over to a couple of cheap led lights which don't put out as much heat. Which was the main reason I did it to avoid heat stress. Seems all good at canopy level.There had been a few hot days here but inside the tent never really went above 30c. Then again it's hard for me to know 100% because I work away for weeks at a time so it's hard to know just how hot it gets some days that im not at home. However on days that are really hot that I've been here to see it doesn't get above 30c. With the new led lights highest the tent get Is about 27c