Question
Hi Jim,
My sister has a raised vegetable garden and it hasn't been doing well for the past couple of years so she took the soil in to be tested. She was told it has a blight and was told to add sulfur to the soil, which she did. Her garden still is not doing well. What are some things she can do to remedy the situation? If she needs to remove the soil and start from scratch, does she also need to start with "fresh" wood for the frame? She lives in southern WI so would a cold winter freeze it out? Would adding a layer of leaf mulch help bolster the soil so the "good" bugs could overcome what is causing the blight? She would like to try a more natural approach to remedy the problem. Thank you for your assistance and we look forward to your response.

Answer
Hi Cindy,  I couple of things happen to soil in raised beds over 2-3 years.  The soil breaks down into smaller and smaller particles which compacts with time and it slows water and air movement through the soil and inhibits root development.  The slower drainage means the soil stays wet longer which tends to lead to fungal and nutrient problems.
The other thing that happens is the pH tends to lower so it may need to be adjusted.
Every year, add 1-2 inches of new organic matter and till it or turn it under as deep as possible. I apply 1 - 3 cubic foot bag of finely ground pine bark or pink bark mulch and 3 - 40 lb. bags of compost or manure for each 30 square feet of bed.
Check your pH.  I'd like to see it near 6.5. The sulfur will lower it substantially.
This fall, plant a green manure on it to be plowed under in the spring.  Annual ryegrass comes up quick and makes a good cover.  
Who told her it had a "blight".  Only a lab could tell by looking at the soil.  Diseased plants might tell you if you have a wilt disease or root rot, so just to be safe plant your crops in different areas of the bed.  Diseases typically hit one or two vegetables and the others are unharmed.  If the whole garden did poorly, its not likely disease, it's a  physiological condition caused by poor growing conditions.  
After planting in the spring, if the garden appears stunted, plants are yellowing or foliage is spotted, send me some photos so we can identify early any issues that we can correct.  Jim