I was wondering why the leaves at the bottom of my mint plants started turning yellow? See photos:





There are also some weird spots on some of the leaves that are healthy:



I water these mint plants a lot. Meaning I water it with 3-4 pints of water in a go and that water stays in a tray that I have under the pot. It should be the issue though. The entire plant looks healthy at the top.

Any help will be appreciated.

The silvery patches on the lower picture may well be caused by an insect but I don't know what sucking insects you have there. Maybe a leafhopper? Have you seen any pests around the plants?

When the oldest leaves die on a plant it can be normal, but I'm not sure in this case. Have you checked the underneath of the leaves for spider mites?