Once you get just one, start growing it. There is a chance it will drop an extra seed some time during regular adult harvest. You can multiply one into several fairly quickly if you tend your garden daily.
I'm not sure the best place for drops, especially without knowing your school or level etc but here is a link to the wiki showing all the drops we know of:
I do garden key limes and if you don't already know, they drop extra key lime seeds quite frequently. So if you already have even 1 or 2 they are worth planting straight away instead of waiting to get the full amount you want first. My second account has 4 wizards with 138 planted each (total of 552), all from just 1 or 2 seeds. I feed tons to pets now I have so many. It's well worth planting ANY you already have!
Alia Misthaven
