Diagnose calmag deficiency/rust fungus??

[Carbar64]

Any ideas if this is a fungus or deficiency?

Northern lights autos, just 3 weeks in to flower? Lower leaves dry and crisp off, upper leaves with yellow/brown spots curling up?
thanks!

 

[9fingerleafs]

That’s a potassium deficiency symptom. If you are feeding nutrients then check ph if you’re not then you may need some during flowering. It’s not that bad either. Many organic soils just can’t hold enough nutrients for when flowering comes. What are growing in?

 

[Carbar64]

That’s a potassium deficiency symptom. If you are feeding nutrients then check ph if you’re not then you may need some during flowering. It’s not that bad either. Many organic soils just can’t hold enough nutrients for when flowering comes. What are growing in?

just growing in store bought compost, and feeding tomato feed every other water - my ph reader defo needs replacing sooner rather than later then! Thanks