This method provides the easiest, most economical way to experiment with drying.  Here's all you do:

1.  Spread food evenly in a single layer on trays--between one and two pounds per tray.  Make trays of wire screening tacked to a wooden frame (about four inches smaller than oven dimensions), or tack cheesecloth to oven racks.

2.  Preheat oven to 150 degrees Fahrenheit (or as low as the oven thermostat will permit).  Place lower oven rack about three inches from bottom of oven and other rack above, allowing space between for two trays to be stacked on a rack.

3.  Dry vegetables for four to 12 hours.  Stir the vegetables several times.