QUESTION: How long does compost last in pots?
ANSWER: Both commercial and homemade compost can last for over one year when sealed, but the overall volume and composition can start to break down and deteriorate significantly after the first year and the microbiological activity can also diminish significantly after the first year, so it is recommended that compost be used within a year for optimal results, though compost doesn’t really expire or become unusable after a year has passed.
If stored properly, compost won’t expire, but it will lose volume and nutrients as time goes by. You can also rejuvenate old compost and used compost as well by replacing lost nutrients and adding in more organic matter.