Growing orchids can be an interesting and rewarding hobby, giving a grower exquisite flowers that are exceptionally long-lasting. Understanding an orchid's growth and potting needs, and when and how to repot, can help ensure a healthy plant that lives for many years. When buying a new orchid, paying some attention to the vase or pot it comes in can help you decide whether immediate repotting is advisable or if it can be delayed.
It's All About Air
Although there are hundreds of orchid types, the great majority are epiphytes, or air plants, which grow with roots exposed to extremely moist air in their native habitats. Most cultivated orchids are grown in pots, with a mixture of bark chips, moss and other ingredients that help keep air moist around the roots but also keeps roots loose, with good air circulation. If your orchid came in a glazed ceramic vase or pot, which doesn't transmit air through its walls, the roots may stay too damp and become prone to rot, especially if there's no hole in the bottom of the vase that allows water to drain out. This could mean the plant needs re-potting, depending on its condition.
Timing Is Important
The best time to re-pot an orchid is usually when it's finished blooming and slows its growth, becoming semi-dormant. If your plant is in a ceramic vase but appears healthy, you could delay re-potting if you don't allow the potting mix to stay wet for long periods. Check the moisture level of the mix every few days by pushing a finger gently into the mix and only water the plant if the upper few inches of potting material feels dry. Water the plant well, allowing water to drain if a hole is present. If not, tilt the pot on its side after watering and keep it in this position for a minute or two, allowing all excess water to drain out.
Detecting Signs of Trouble
If an orchid pot drains poorly and the potting mix tends to stay wet, there can be insufficient air around the plant's roots, which can cause problems. The signs of trouble in an orchid are different than those seen in a plant grown in soil, and can include drooping leaves that sometimes develop shrunken areas, or roots that become slimy and later shrink and dry up. You can check the health of an orchid's roots by gently exposing one or two near the top of the pot and checking their condition. Healthy roots are thick, firm and white or greenish on their outer surfaces. If the orchid shows signs of damage, it should be re-potted even if it's still in flower.
Re-potting the Plant
To re-pot an orchid, remove it gently from its vase or pot by thumping the sides and bottom of the pot to dislodge it. Shake potting medium off the roots and examine them, trimming away any that are mushy or dried up with shears or a sharp knife. Be sure to disinfect your tool by wiping it with rubbing alcohol between cuts. Choose a slightly larger new pot that has one or more drain holes, or use a pot designed for orchids that has sides with slits. Place some gravel or packing peanuts in the pot's bottom to improve drainage, position the orchid in the pot at its original depth and pour new, pre-moistened mix around the roots, gently packing it down. Keep the plant in a shaded location for a week or two, misting the plant and surface of its mix twice daily until you see new upper growth.