A good soil mix is the most important part of growing terrestrial
orchids, breeder Bill Mathis says. That means preparing the hole
before you plant, whether you plan to grow the orchids in raised
beds or in a mixed perennial border.
Here are his planting suggestions:
The most popular hardy wild orchids are lady's slippers, which
like a loose, well-drained soil. Mathis recommends one part
composted wood chips or leaves and three parts coarse sand mixed
with a little coarse Perlite. Because drainage is important in
preventing fungal root diseases, he suggests testing a potential
planting site by digging a hole 12 to 18 inches deep and about two
feet in diameter and filling it with water. If the hole drains in
less than four hours, it's acceptable.
Add a couple of inches of gravel or coarse sand to the bottom,
and fill the hole with the soil mix to within two inches of the top.
Place the lady's slipper roots on the surface, carefully spread them
horizontally, and cover with the soil mix until the shoot tips of a
bare-root plant are barely under the surface.
Newly acquired bare-root plants may benefit from being soaked in
cool water for 15 to 20 minutes before planting. After planting, add
a leaf mulch to the bed to help maintain consistent moisture.
The yellow lady's slipper is considered the easiest to grow in
the garden, and like most of its kin, it thrives in high shade. (In
this climate, the showy variety prefers more sun, but midday
shade.)
All hardy wild orchids, and especially lady's slippers, have low
nutrient requirements, Mathis says. He fertilizes once a month with
a solution of Miracle-Gro all-purpose plant food that's only 25
percent of the recommended rate. Stop fertilizing as blooms
fade.
In winter, these orchids benefit from a mulch of three or four
inches of shredded leaves or pine needles, to help stabilize soil
temperatures. But remove it carefully in early spring to allow
shoots to emerge.
