Hostas are herbaceous perennial plants that, although flowering, are grown primarily for their striking foliage. They thrive in shady areas of the garden, which is an added bonus. Although the plants aren't too particular as to soil pH (any pH between slightly acidic to slightly alkaline is fine), they do much better in a fast-draining soil texture. By incorporating charcoal into the planting site, you can not only create a better draining soil, but aerate the soil as well.
Purchase pre-ground horticultural charcoal online or at garden and hardware stores. You can also use the briquets available at the supermarket, although they will need to be ground into smaller chunks, according to Mingxin Guo, assistant professor of agriculture and natural resources at Delaware State University (NPR).
Dig up the planting area to a depth of 12 inches, crushing the soil with a gardening fork. Remove any rocks or old roots that turn up. Level the bed with a rake.
Pour a 3-inch layer of compost onto the planting bed and mix it to a depth of 8 inches. Again, level the bed by using the rake.
Add a 2- to 3-inch layer of charcoal onto the soil. Mix it as you did the compost to a depth of 8 inches.
Dig a hole for the hosta plant. It should be twice the diameter and the same depth as its current pot.
Place the hosta's roots into the hole and fill the hole with soil. Pack the soil around the base of the plant.
Water the hosta until the water puddles. Then, lay down a 3-inch layer of mulch, which should be spread out 1 foot from the base of the hosta.