Rule of thumb: How many plants we should pot.
Spider plants, and boys purchased 4- inch; would like to place in large hanging baskets
Certified GKH Gardening Expert
There is no real good rule of thumb. How many you plant is plant dependent, and sometimes, not important. In this case with the spiderplant- They are very comfortable being rootbound and crowded.
As long as you plant with an inch or two between plants then they will be happy. More importantly is the care that they receive. This article will help: