Whats this brown crud

[Brigand13]

These are 2 weeks into 12/12 and all are well but this 1. The plant on left looks fine but the other developed this brown/ rusty stuff on upper leaves in just a few days. All get same nutes etc. Any ideas what this is?

 

[netwerx]

looks like heat burn to me. Can you get a close up?

 

[Mr.Hades]

Theres water on the plants correct? You prolly should stop spraying water on flowering plants. Could also be nute burn. If its not the same strain, some strains are more sensitive to nute mixes. How is your humidity?

 

[Brigand13]

Thanks for the help. We can rule out heat burn, the top is in better shape than the leaves below and the others dont look like this. They are on FF nutes, currently at dosage on bottle and cal/mag at 1 tsp gal. Some other plants are showing some rusty brown specs and small areas on edges. They are mostly on upper leaves. No pests or humidity problems. I feel certain this is either too much or too little of something but I'm not experienced enough to know which

 

[Mr.Hades]

It looks to me like you are burning your plants...

When was the last time you transplanted? Are they rootbound? If I were you I would do a flush with plain water, check your humidty and drainage in soil. Then next watering, use only a 1/4 of what it says on the bottle until growth picks up and then up to half of what it says on the bottle...

With most fertilizers it is east to feed too much, even when you are following guidlines on the bottle. A good rule to not over feed is, If it says use 3 tablespoons per gallon use 1. Also dont constantly feed, plants need just plain water sometimes as there are plenty of nutrients usually in the soil between feedings.

 

[Brigand13]

they have been in 3gal pot since they were app 3 weeks old from clone. I never had problem with root bound before. 1 of 2 white widows has this(the 1 above) and 1 of 4 skunks has it. Here is a pic of the other ww.