I have had an orchid for about 4 years. It is a small variety and it blooms every year. It came in a very small pot and when the roots started coming over the top, I transplanted it to a larger pot. Now, the roots are well over the top and down the sides of the plant pot, but I don't think I should transplant it as it is blooming. I thought i could perhaps transplant when it stopped blooming, but after it put out 14 blossoms this summer into the fall, it took a few days off when lo and behold I saw the beginnings of new blossoms. It is currently blossoming and there are 4 more buds coming. I water it with 1/2 cup of water once a week and it is in a north, north-west facing window and appears to be very happy there even though it gets quite a lot of sun in the summer and it is chilly in the window during the winter. The plant pot it is in is about 6" across the top.........how much bigger should I go and should the roots be under the planting mix? thank you so much
Windham County Vermont
Hi Windham County!
From your description, it sounds like you have a very happy Phalaenopsis Orchid (aka: the Moth Orchid).
By pure genius, you set your Orchid in just the right location to get it to re-bloom regularly. You'll find that allowing your Orchid to experience cooler night temperatures in the fall (no lower than 50 degrees F), you can help them set new buds. Since Phalaenopsis Orchids can form new flowering branches along old flower spikes, be sure to watch the older spikes for signs of new buds. Never be in any rush to cut the old flower stalks until they've died off.
When to re-pot your orchid
The best time to repot is when new growth has started and not necessarily after the plant has finished blooming.
When your plant has overgrown its pot or the bark has broken down so that it looks like mulch, drains poorly and holds too much moisture - its time to repot.
Phalaenopsis tend to grow along the surface of the pot, sending just some roots down into the growing medium. Remember to trim any dead, spongy, discolored, or damaged roots when repotting.
Pot size is more about root size than of plant size. Trim up the roots and then determine how large a pot you need to maintain stability. Generally, if you need to go larger, repot in a two inch larger pot. If you have a six inch pot now, then don't go any larger than eight inches. However, don't been afraid to set your orchid right back into the same container after your trimming indicates it will work. Orchid containers with openings along the sides are preferred, but a clean clay or plastic pot will work nicely, too.
Air Roots vs. Potted Roots
When repotting, only sink the roots you found within the growing medium back into the pot. As noted above, you Phalaenopsis sends out many surface roots and they will continue to be happy on the pot surface.
University of Maryland Extension
Washington State University Extension
Michigan State University Extension
I do hope this has been helpful!
UVM Extension Master Gardener Volunteer
As Judy’s comprehensive answer said, plants with air roots have different needs than those with roots below ground level. Orchids are ‘epiphytes,” meaning above (epi) roots (phytes). In their native environment, they use these roots to secure themselves to limbs of trees, among other surfaces, and get all of their water and ‘food’ above ground. Their ambient air is humid; the temperature is warm; the sunlight is filtered, and any rainwater drains quickly. So, combining our responses, you can create a similar environment. I agree with Judy that you are obviously doing something very well! Congrats, and maybe you’d be interested in Master Gardener classes!