Weird yellow spots on leaves

Cannabis Leaf Symptoms & Plant Problems | Marijuana Nutrient Deficiencies | Grow Weed Easy

 

Ok let's try this link

Plant Doctor - Diagnose Your Plants! | Grow Weed Easy

It's on there.

 

That is some weird markings. The new growth looks good though. Looks like your growing in coco. What kind of nutes have you been using?

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These aren't similar at all?

 

Aah haa! It's a fluctuating ph issue!

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I used 6.2-6.4 for Coco/soil mix

 

Mixed, not layered.

 

I don't understand the purpose of using both coco and soil when both require different pH levels. Can someone explain?

 

You can add perlite to the soil and achieve the same goal without having to deal with the pH problem.

 

Nope

 

I agree mic. Perlite is a better medium for boosting drainage, aeration, and water holding capability of soil. Coco does have many of those properties and as long as you only used a small amount, maybe 10% it wouldn't effect the ph buffers in the soil I don't think.

Coco does seem to have some very beneficial properties and I wouldn't automatically think that mixing it with soil would be a bad idea. The promix I happen to use (sunshine promix 4) is heavy in coco. It's peat moss, coco, perlite, dolomite lime, and organic wetting agents. Even though it contains significant coco it behaves a little more like soil and isn't as picky about PH with the dolomite lime for a buffer.

I'm a huge perlite fan. Many coco growers mix perlite in with their coco. I won't grow without mixing in at least 10% extra perlite in whatever medium I use even if it's already in there. I feel like it's one of the secrets that experienced growers learn. In order for cannabis to grow and expand rapidly it needs a very loose and well aerating medium. Most all bag soils and mediums straight out of the bag get too compact and choke the roots for air preventing rapid growth. A generous mix of perlite solves that. Many growers use up to 30%. I'm usually about 15%.

 

One of the properties of coco in general is that it takes more cal/mag to grow a healthy plant in it then other mediums. Considering that and your symptoms I believe you may be low on magnesium.

It may be caused by lockout from the ph range being off but when you get patterned yellow areas right in between the leaf veins only the most likely culprit is lack of magnesium.
Magnesium Deficiency | Grow Weed Easy


The spots aren't usually so isolated as they are in your plant. They usually fade into the green areas. Its also not very typical for a plant that young to have deficiencies yet. It's barely had time to deplete the medium. 95% of the time when you see a deficiency in a plant that young the ph is off preventing absorption. If I were you I would feed between 6.2-6.5.

 

I find those charts kind of funny. When was the last time someone had a boron, copper, or zinc deficiency? Most of those deficiencies will never happen to you if you have any kind of comprehensive feed schedule. The plant needs Nitrogen, phosphorus, potassium, calcium, magnesium, and iron. Everything else it needs in amounts that are so small they make up less then 1/100th-1/1,000,000th a percent of total nutrition.

If you are ever really deficient 99.9% of the time it will be one of those 6 elements. Sort of seems silly to me to list boron deficiency first in a list like that. Most people who think that's what they have are misdiagnosing. That's a super unlikely deficiency to have.

"My plants were sad and I couldn't figure it out. Then I realized that I just needed to add some boron and they took off like wildfire." - said no person ever.

 

I had originally thought it may be a magnesium def. also.

I had a copper deficiency 2 grows ago, but I agree that it's very rare to have those deficiencies without N-P-K defs.