Phalaenopsis Orchids?

It is best done in late spring or early summer after blooming has completed. Phalaenopsis plants must be potted in quick draining mixes, such as fir bark, tree fern fiber, chunky sphagnum peat, charcoal, perlite, or combinations of these. Root rot will occur if plants are allowed to sit in an old, soggy medium. Your young plants should grow fast enough to need repotting yearly and should be potted in a finer grade medium to allow good root contact. Mature plants are potted in a coarser medium may stay in the same pots for years, provided that medium is changed when needed. To repot, remove all old medium from the roots, trim off rotted roots, and spread the remaining roots over a handful of medium in a pot. Fill the rest of the pot with medium, working through the roots, so that the junction of the upper roots and the stem is slightly below the medium. Be careful not to leave large air pockets in pots. Use a stick to push the medium in between the roots. Keep plants in shade and wait for one to three days before watering.

Fertilizer should be applied on a regular schedule, especially if the weather is warm when plants are actively growing. Application of a complete fertilizer, such as Miracle Gro, Peters 20-20-20 or similars, at a rate of half to one teaspoon per one gallon of good quality water at each watering. Reduce this frequency to every other or third watering when it is cool. Make sure that an ample amount of water is applied to allow some excess water to drain from each pot. Water with a high salt concentration should be avoided.

Also humidity is important. If it is lower than 40% in the home, set plants on trays of gravel, partially filled with water so that pots never sit in water. Grouping plants together can slightly raise the humidity in the immediate surrounding area.

You can re-pot Phalaenopsis anytime the plant's roots are actively growing. If the white roots have a green or brown pointy tip (color depends on the specific plant), they are growing and will take nicely to a new pot.

I use the 15-30-15 Miracle-Gro for my Phals at home at the rate recommended on the box (a teaspoon to a gallon), which is about 125 ppm N, and my Phals bloom fine. At work we use a 13-3-15 at 125 ppm N, and that works great, too. (Actually, the fertilizer we use at my work is famous in the orchid world for producing amazing results).

Phals can be transplanted any time of the year as they are not affected by the seasons (they are extremely hybridized). They make new roots year round so it will be fine no matter what time you re-pot.

Do not use miracle grow. Use a 20-10-20 urea free (very important) orchid fertilizer. Start out at a quarter strength and slowly up it to like half strength.