Wash a gallon plant pot with soapy water. Rinse the container with 1 part bleach and 9 parts water. Pups will live up to one year in a gallon container without having to be transplanted.
Fill the container with a half-and-half mixture of peat moss and sand. This gives the agave pup lots of drainage and a loose texture. Loose soil makes it easier for the roots to spread out.
Dig around the pups with a sharp-edged hand shovel. Check to see where the pup is connected to the parent plant. There should be a connection made of plant roots.
Cut the roots that connect the pup to the parent plant with the edge of the shovel. Leave at least 1/4 inch of roots on the pup. Remove any damaged roots with a pair of sharp pruning shears.
Push the agave pup into the soil of the gallon container. The pup will start to grow roots in a couple of weeks.