Peanuts should be large enough not to fall out thru drainage holes, so you don't need any mesh.
I would cover them (the peanuts) with some landscape felt before filling the container with the soil since I wouldn't want to have peanuts mixed up with the soil.
Rina

you can use the stuff that needle pointers use, and bonsai folks. plastic mesh, about 1.50 for a huge 18x18 inch chunk. makes a bunch of 2x2 squares ...

I use plastic/fiberglass window screen.