What's the problem with these leaves?

[Javier-de-Tandil]

Hi to everybody: the following pictures are from leaves of my growing hops. Are they overwatering, underwatering, pest? Because their tips are yellow. What's the problem with these leaves? Thank you for your answers!!

[gregscsu]

I believe yellow tipped leaves can be a symptom of both under and over watering.

[adruma]

Put your finger in the dirt. Do you feel water, does your finger come out wet? If so, ease off on the water a bit.

[roffenburger]

The last picture-leaves in the background look "speckled." turn them over and look really hard for mites. They are tiny and leave a network of web on the back side of the leaves. Little SOBs if you ask me.

[Javier-de-Tandil]

The last picture-leaves in the background look "speckled." turn them over and look really hard for mites. They are tiny and leave a network of web on the back side of the leaves. Little SOBs if you ask me.

Yes!!!! I found some mites on the back side of the leaves. They're almost invisible! Well, at least I know the problem, already. Now, I'll kill them. Thank you very much for your answer!