What is the best soil for transplanting orchids? Should I put rocks in the bottom to ensure good drainage? Also do I need to stake all flowering shoots? Is feeding them recommended or should I just continue to give them plain water? I appreciate any advice that you can offer.
There are many different species of Orchids and they don’t all have the same requirements. However, the chances are very good that you have a Phalaenopsis Orchid, so I will respond accordingly. If you have a different Orchid species, let me know.
Most Orchids do not grow in soil potting mixes. This is because in nature they are adapted to living up high attached to the bark of tropical rainforest tree limbs. Their roots are normally exposed to the air in humid conditions and will easily rot if planted in damp soil. In this respect, Orchids are different from most other indoor plants.
Potted Orchids are normally grown in bark chips or sphagnum moss or a combination of the two. Better plant shops sell small bags of Orchid mix. The mix should be without any soil and should be very porous and lumpy.
Orchids – even mature ones – rarely need pots larger than 6-8 inches in diameter. Be sure that the pot has drainage holes so that excess water flowing through the porous potting mix has a way to escape and not rot the roots. Using rocks or other “drainage material” in the bottom of the pot is an outdated and discredited practice. Drainage is never a problem if the pot has drain holes and the potting mix is properly porous.
I would wait about two years before repotting an Orchid. It takes about that long for the potting material to start to decompose. Gently remove the old material and replace it with fresh Orchid mix, keeping it in the same sized pot. It is fine if some of the roots grow over the rim of the pot; Orchids are not like other potted plants.
Never repot or disturb the roots when the Orchid is in bud or bloom. The flower stems (called spikes) are staked only to hold them upright so they are more visible. It is your choice as to whether you want to do this.
The easiest way to water Orchids is to take them to a sink and flush clear water throughout the potting mix. The excess water will run through within a few minutes after which it can be returned to its normal location in bright indirect light. If your tap water is on the hard side, use filtered or distilled water. Once a month, water with a solution of half-strength general purpose plant food or fertilizer.