As you continue your vegetable garden from year to year, avoid planting the same or closely related vegetables in the same spot. Otherwise, there could be a buildup of diseases and/or insects in the soil that prefer that plant family. In general, different plant families are not susceptible to the same diseases and insects. By changing the crop planted in a particular location every year or so, you can prevent many disease and insect problems from building up to serious levels. An example of effective crop rotation would be to plant peas or beans in the spot where potatoes, tomatoes, eggplants, or peppers were planted the previous year.