Sunday, February 17, 2008

Orchid repotting 101


Saturday my friend Lee, above, offered to help repot orchids belonging to me and another friend, Maryann. Lee has a fabulous greenhouse attached to her house where we all met in the morning. It was 20 degrees outside when I arrived at her house at 10am. Inside between the wood heat and the solar energy in the greenhouse it was like a trip to Florida! I was in bare feet, rolled up jeans and a tee shirt within minutes! What follows is a loose but hopefully helpful, graphic account of the repotting process.
Lee recommends potting orchids in sphagnum moss. It holds moisture nicely but also is very light and airy. With most of the common orchids repotting should take place every year and no more than two. I was guilty of a three year stretch with my three orchids and it showed. Keeping orchids in fresh potting material is essential to their health. Below is a bag of the sphagnum moss
and some soaking before it is used for repotting.
The first orchid we repotted is a cymbidium shown below, ready to remove from the pot. It had just bloomed but the blooms fell off rather quickly and although there is good new growth, it needs repotting. The potting material was heavy and dense.
Have a jar of bleach and water nearby with some sticks to use for the cleaning process. For each orchid to be repotted, dip the stick in the bleach/water to sterilize before using.
Lay the orchid on a work surface and with the sterilized stick carefully pick away all the planting medium from the roots of the plant. Do this until all the medium is removed. Throw the old medium away; do not reuse it.
Once the roots are free and clear you can then check the bulbs. If they are hard they are still healthy. Quite often you will see new growth. The roots which dangle below should be firm. Any that are soft and brown should be cut off. Any that are broken should be cut above the break.
Here you can see healthy new growth.

Lee found this wonderful pair of gardening scissors in Home Depot, perfect for this type of intricate work.
After the orchid has been cleaned and the roots clipped as needed, soak the roots in a sink or pan of water for a few minutes.
Clean your pot completely before repotting the orchid. Make sure to use a pot less than 2" larger than the last one. Using a pot too large for the root structure will result in the potting medium to hold excess moisture which will cause the root's health to suffer. Fill the pot half way with the moistened moss. Then add the orchid to the pot and hold it upright as you add the moss around the plant, using the stick to work it in and around. Do not pack the moss tightly, just enough to support the roots and plant. This picture shows the pot being filled but it needs moss to come up about an inch below the top of the pot.
Below is an example of scale on an orchid. They are little brown bumps. Take the plant over the trash can and scrape off these scales, being careful to get each one. After they are removed wipe all the leaves with rubbing alcohol which inhibits the scales to come back. Be sure to get at all the affected areas. Once a week, retreat with alcohol until the signs of scale are gone. At the first sight, this is the best method of treatment.
Here are my three orchids, back home after the journey. Left to right are a Phalaenopsis; Paphiopedilum or Lady Slipper Orchid; Cattleya. They are in a south facing window which only gets 2-4 hours of sun per day (when it's sunny!). After repotting don't feed or re-water for a month. The orchids have gone through a bit of a shock and need to readjust. Once you see new growth emerging comence with feeding and watering. Feed orchid specific food at the rate of "weakly/weekly". It is better to give a weaker feed solution weekly. Also mark your plant label stick with the repotting date so you won't forget when it is time to repot next year. For more information on orchids click here http://www.orchidweb.org/

2 comments:

  1. Nice. My father built a greenhouse on my childhood home and he raised orchids and cacti.The cactus would get so tall he ended up donating them to Longwood Gardens, a world-famous estate and gardens that was the former residence of Pierre S. du Pont.

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  2. Anonymous6:31 AM

    Hi Nancy,
    Thanks for your gracious comments. We did have fun. It is great to share the greenhouse with others & giggling is good. Come again.
    Lee

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