(a) Before planting the potatoes, he clears the land and weeds all the wild plants. The next thing he does is to prepare the beds.
"Clears the land" sounds like the American pioneers, chopping down trees to plant fields of corn.
(a) Before planting the potatoes, he weeds out all the wild plants and then prepares the beds.
If you want to keep your original, drop the "to" in "to prepare."