i have orange rusty looking spots on some of my big fan leafs and even on a few small ones, its some kinda of diffenecy but i cant figure it out, I feed with fossil fuel, big bud, advanced nutrients veg, 2-2-1, fox farm grow big, shultz plant food 10-10-15 I use tap water, i let it sit for 4 days or so, because when it comes out the ph is about 8 and it usally stays 7-8ph i cant get it any lower, Also this plant is budding and is random bag seed
Rust spots are typically caused by two things.....overfertilization and overtranspiration. The first is obvious, too much nute. Flush well and start over with nutes at 1/3 or 1/4 strength. You are feeding quite a varied cocktail of goodies, cut back for a while. The second, overtranspiration is caused by too much heat and light. In its attempt to keep cool, it basically sweats out too much moisture. You may need to move the lights back a few inches, or provide better ventilation depending on your room temps. The good news is that as the plant gets bigger, overtranspiration is a less common problem.