Sphagnum moss, obtainable from a florist, is a good liner, because, even when wet, it holds a lot of air. If you start with dry moss, before placing it, moisten it well with a solution of weak fertilizer for the benefit of the plant roots. Osmunda fiber, procurable at garden centers, is a good substitute for sphagnum, because it decays slowly, but it has the disadvantage of drying out quickly and is an unattractive dark color. Because Osmunda is springy, pack it firmly so drainage will be adequate.
At the base of the wire frame, you can insert a saucer to catch excess water. This will then hold a supply of moisture for roots, and the saucer will prevent a drip-through to porch or terrace. Some types of baskets, among these clay, come with saucers attached.
How to Plant a Basket
To grow plants only in the center of a moss-lined
basket, fill with soil and plant with care. For immediate effects, select fairly large plants, all ready to bloom. You can add hanging plants, ivy or vinca, at the edge, with upright growers-wax begonias or zonal geraniums-in the center for height. This is a simple variation from the typical hanging plant of ivy-leaved geranium, lantana, fuchsia, or tuberous begonia.
With some kinds, strawberry begonia and star of Bethlehem (called also Italian bell-flower), you will want plants to creep down the sides of the basket for a cascade. For this, first place moss in the basket and spread soil to the halfway mark. Through the wire openings at the sides, insert young plants, laying them carefully on the sides. Then pack soil around the root balls. Repeat higher up, adding more moss, soil and plants until you reach the top center where larger specimens will be planted upright. At the surface, make a central depression to catch water.
Fertilizing Basket Plants
After planting, suspend the basket in a barrel of water, a pail or a garden pool up to the rim until it absorbs enough moisture for the surface to feel wet. Then hang up the basket to dry. Or dip it in a weak fertilizer solution if you did not soak the moss previously. After this treatment, feeding will not be needed for two weeks. Thereafter, dip the basket in a fertilizer solution once a week. This method enables plant food to spread throughout the moss lining. If you prefer, you can feed plants with a solution poured over the soil surface.
For baskets, use the soil mixture recommended for window boxes, unless plants require something special.