Brown spots on lowest leaves

No, it's appearing all over the plant. But for a calcium deficiency, it actually seems too uniform between the leaf veins. That's more typical for a magnesium deficiency, which would also come with light discolorations. I'm guessing it's a particularly nice calcium deficiency with an upcoming magnesium deficiency. That should actually progress quite quickly. Flush the plant with pH and 20 percent runoff. Then water with pH and lightly fertilized water, including a light dose of CalMag. It should start to feel better quickly. If you have it, or can get it quickly... you can mix half a gram of Epsom salt with a liter of water and spray the leaves with it. That will give it magnesium back. Happy Gardening 💪😎