My home garden
Why are my vegetables not producing as they use too? The leafs turn yellow and fall off. Use to have a beautiful vegetable garden.
Eaton County Michigan
Without knowing your crops and conditions it's hard to say what the problem could be. First off, have the soil tested. This can be done through MSUE at http://www.msusoiltest.com/ . Certain nutrients may have been depleted from the soil and need to be replenished or perhaps the pH of the soil has changed and needs adjustment. The soil test is a great place to start. Some other things to consider include a change in the water source. If you have been growing vegetable in the same area year after year there may be a buildup of pathogens (diseases) or insect pests. If you have a butternut or black walnut tree nearby it can poison the soil for some vegetables.
I hope this helps,