Planting wire baskets isn't as easy as planting plastic hanging baskets. But whichever type of basket you are planting, begin by choosing the right type of soil. A successful soil mix for hanging baskets must be lightweight and able to retain moisture.
Make your planting mix.
One way to achieve a suitable mix is to start with a bag of high-quality potting mix and add perlite or vermiculite at the ratio of three parts soil mix to one part additive. Perlite and vermiculite both lighten the mix; vermiculite also absorbs and retains water. Both are available at garden supply stores. Mixing in time-release fertilizer granules is a good idea, too.
Soak sphagnum moss in water for at least 10 minutes.
Support a round-bottomed basket on a large pot or bucket to keep it upright.
Begin to line your basket by laying sheets of dampened moss — about 1 inch thick — along the bottom and halfway up the sides.
The steps for planting a solid basket are similar to those for planting any small container.
Loosely fill the basket with soil to just below the moss level, and then resume lining the sides with moss.
Continue right up to the top until the moss covers the rim area. Use plenty of moss so you don’t have any gaps, and fill loosely with more soil until you reach the top.
Begin planting the sides by starting near the bottom.
Carefully open a space between the wires and through the moss. Loosen any tangled roots, and insert the roots through the hole and into the moist soil. Use more wads of moss to tuck the plant in securely, and gently bend the wires together above and below the plant.
Continue planting the sides.
Allow at least 3 inches between plants as you stagger them evenly around the sides. The more plants you place here, the quicker things can grow together and the less basket you’ll see later on.
Plant in the top of the basket.
Space plants evenly with the tallest in the center, allowing at least 3 inches between plants. Set them so that the soil level is slightly below the rim. Again, the fuller you plant the top, the quicker your basket can become a mass of color and texture. Be careful not to plant right over the roots of side plants near the rim. Firm the top plants in, adding more soil as needed but keeping the level below the top of the moss.
Attach the supports and hang the basket, and then water until water drains freely.
Replace any moss that may have fallen out, tucking new moss securely around the plants and water daily as plants become established. Hanging baskets dry out faster than most other containers.