Rhubarb

How do I grow Rhubarb and care for it?

I have had a rhubarb plant in a large pot for about two years and feed and water it regularly, but some of the stalks are soft. Should I be feeding more and re-potting?

My rhubarb has not performed as well as it used to. I put homemade compost on it each year and the plant grows okay, but then some of the green leaves wilt or get reddish brown spots. Is it a natural process from the relentless sun or is it a disease?