Most of last year's fertilizers and pesticides should be fine to use this year unless they were:
1. Stored in direct sunlight
2. Stored in a hot place for an extended period of time
3. Exposed to water and got wet
4. Contaminated by a pesticide, gas, or oil
5. Frozen for an extended period of time
Potency is reduced with time even if these situations do not occur, but one year is not enough time to discard the material. For more information on storing pesticides see: Storing Pesticides Safely. For more information how to select, handle, apply and dispose of pesticides, visit the eXtension site Homeowner Pesticide Safety.
