Q.How To Plant Multiple Horsetails In A Planter
I have a 31½”W x 11¾”D x 15¾”H planter. I just purchase 20 one gallon horsetail plants. I want to create a thick full privacy screen in the planters. How much space should I give each plant to grow into a screen?

Certified GKH Gardening Expert
Spread them all as far apart as you can in your container. They spread very quickly. It will be important to divide them every year, as they will overcrowd the container, quickly.
Here is an article that will help with the care of the plant:
https://www.gardeningknowhow.com/edible/herbs/horsetail/horsetail-herb-growing.htm