Asked April 23, 2021, 12:26 PM EDT
Ramsey County Minnesota
Thank you for writing.
Fertilizer pellets last about 9 months after potting but in a bag, without water, the nutrients have no way to leave the soil. I would only fertilize if the potted plants did not grow properly.
Many people add too much nitrogen which can cause plants to shift from flowers and fruits to simply have a lot of leaves.
If it is really important, you could put the potting soil in your garden or windowboxes.
I hope this helps.