Ordinary grasses are known for their protective qualities. When charged with magical intent, they’re excellent for protecting the garden. Early in the spring, cut some tall grasses. Just a handful will do. Tie the bunch of grass in the middle with some jute twine or a few more stems of grass. As you stand in your garden, hold the bundle of grass. Charge it with these words:

Green and noble grasses,
Guard this garden as
each season passes.
Guard the seeds I plant
with my own hand.
Protect the vegetables and
the flowers so grand.

Lay the bundle of grass in a corner of your garden. Leave it undisturbed. Let it return to the earth from where it came. Repeat this spell next spring if you wish.