Here is a decidedly unscientific response: We leased some land in Southern Cal to a family which first raised strawberries and then tomatoes on it. Subsequently, we planted Avocados on the same land. We traced the problems which ultimately led to taking that parcel out of the Avocado orchard to the tomatoes. If memory serves, and it must go back to the 50's, we concluded that, unless you rotate crops in the same family (eg. potatoes) on less than a 3 or four year schedule, or if you are working in marginal soil, the problems will not be severe. However, if you have blight or any number of other persistent diseases, even heavy composting will not cure the problem. If you have the room, establish a rotation and stick to it. With the spread of late blight, I think it's doubly important to keep the reservoir of infectious diseases at a minimum. On a related topic, we suggest that you not compost potatoes, potato plants, tomatoes or other related plants even if you use a rapid compost regimen. On a small scale, there are always margins of a composting mass which don't reach or hold "high" temperatures long enough. RY >At 11:27 PM 2/17/99 EST, you wrote: >>Do you rotate the location where you plant tomatoes from one >>year to the next? >>I've been growing tomatoes for about 10 years. I have always heard that I >>should rotate where the tomatoes are grown each year to help prevent soil >>borne diseases. Last year, on a different maillist, many people said that >>rotating tomatoes isn't necessary. If I remember correctly, two of their >>reasons were 1) healthy plants could handle typical soil borne diseases >>fairly well, and 2) soil high in organic material would supress those >>diseases. --------------- Richard Yarnell, SHAMBLES WORKSHOPS | No gimmick we try, no "scientific" Beavercreek, OR. Makers of fine | fix we attempt, will save our planet Wooden Canoes, The Stack(R) urban | until we reduce the population. Let's composter, fly tying benches | leave our kids a decent place to live. --