While gauge is not important, your knit fabric should be relatively tight. If your fabric is too loose, adjust your needle size accordingly. You don’t want the stuffing to show through.
Description from MagKnits.com:
Knit vegetables have more uses than you’d think. You can use them as decorative centerpieces for your table. Toys for children, pets, or yourself. Fill them with something heavy and you’ll have an interesting paperweight. Fill them with something fragrant and you’ll have a unique sachet. Or let everyone know how much you like to knit and start filling your fridge with them.