I was given seeds from a friend (more specifically I was given Heirloom Calla Lily Seeds and Bundle of Buttercup Seeds) but when I go to The Subeta Gardens it gives me this message: You do not have any seeds to plant! Come back to me when you do!

Is there a step I need to take first before I can plant my seeds?

These seeds aren't real seeds. They're an old sort of event item, where they could be planted to help clean up Centropolis. I'm not sure if you can still do anything with them here but I don't think you can.

This is a list of the plantable seeds at the gardens.

Ooh okay thank you for the information. :) I bookmarked the page of plantable seeds that you linked me to for future reference so thank you for that as well! I'm going to go buy a different kind of seed now.