Cut them off from the parent plant with a sharp knife. If there are any roots at the bottom, try to save them, but chances are there won't be any. That's not a problem. The next step is rooting them.
Douse the cut part and the bottom of the plant with some garden sulfur and some rooting hormone powder. Rooting hormone powder is pretty easy to find at your local Home Depot. I had to go to a real nursery to get garden sulfur. Anyway, the idea is to keep the little plant from rotting while giving it time to grow its own roots.
|Sago palm pups being rooted|
Water them occasionally, but don't overdo it, and be sure the water drains away. The "bulb" itself will keep the plant alive for several years, and it will take at least one year for the roots to develop.
Once the roots are developed, the new plant will push a flush of leaves. When it does, it's OK to start watering it, a little more, and the plant can go into its permanent home. It takes patience, because cycads grow very slowly. The plant in the photo above is probably about thirty to forty years old.
By the way, you don't have to root the pups, but it's a good idea to cut them off of your sago, anyway. They take away energy from the rest of the plant. But why not root them? I'm sure forty years will go by pretty fast!