Hello Louann,

The most likely cause of curling leaves is heat stress and water deficiency. Considering how high your container mixture is in organic material, it might be draining and drying out much more rapidly than you realize.

A secondary cause of curling leaves is nutrient deficiency. Another side effect of mixtures with excellent drainage is that nutrients easily leach through the soil with heavy waterings.

The purpling of the leaves may be an indication of phosphorus or potassium deficiency.

You mention the lower leaves are yellowing and mottled. This could be an indication of a fungal infection, or more likely, the plant is moving nitrogen from the lower, “spent” leaves to the new growth. This could be why the new growth is smaller than you expect.

Here is a Penn State article that addresses container grown tomatoes and organic alternatives: https://extension.psu.edu/container-grown-tomatoes

I hope this helps.