Swiss Chard Stems Slowly Turn Brown And Leaves Discolor With Hot Weather

Question From: S. Fetlock - MICHIGAN
Q: I grow swiss chard every year. On occasion, and this year, some of the plants in mid august (hot weather in SWMichigan) have stems which slowly turn brown, simultaneous with leaves going off color as well. No evidence of insects or mildew. I dug up one; the root is healthy looking, solid, white. I can find nothing on the web that fits this description of a problem.

A: These are cool weather plants, so now is the time to start a second planting. Best And Happy Yardening, Nancy