Why are my plants dying?

Contact your County extension service and give them details on what types of plants and possibly getting your soil tested. Not knowing where you live, or how your soil has been prepared, or what plants you're using it's a little hard to give you good information. However, they will know everything including what's in your backyard! Great resource

must be in the soil....

what plants are you referring to, what is the location, how did you plant them?

If your water comes from the "city" well, put the water up in containers. Then 24 hours later some of the chemicals will have evaporated. I have had to do this in some cities I have lived in.

I had a beautiful garden once that turned to mold overnight. I was told it was in the soil and half the pumpkin patches in our general area had the same problem.

In addition to having the Extension Office test your soil, you could also have them test your water as well. If you are on city water, they make have changed what they put in it and if you are on a well, you may have a bigger problem then dying plants...nice to know either way.

So much of this kind of problem has to do with the weather were you live. Research on-line or call your local garden centers and they will probably have some answers.