When is the vacation over?

Orchids are tropical plants, but that doesn’t mean always hot and humid.  There are warm growing orchids (Dendrobiums), Warm-Intermediate Orchids (Paphiopedilum and Phalaenopsis), Intermediate (Cattleya), and cool growing orchids (Cymbidiums). Most home hobbyists have orchids in the middle two varieties and this temperature range is 60 to 80 degrees Fahrenheit. So, when the night time temps begin to fall below 60 it is time to think about ending the vacation.

Temperature variations of 10 to 15 degrees between day and night cue orchids to think about blooming. I challenge my orchids by letting the temperatures dip below 60 and have found this does stimulate the growth of flower spikes. 

My Cymbidiums are an exception; they need to be vernalized to re-bloom and can withstand temperatures between 20 and 40 degrees Fahrenheit (!). I leave my Cymbidiums outside until the nighttime temperatures dip to the upper 30s and they bloom reliably once indoors.

Prepping to come home.

When you bring any plant indoors from outside you want to be sure they are not bringing anything home they didn’t leave with.  You want to be sure nothing has taken up residence the in the spaces between the bark chips or on the leaves or that an infection hasn’t invaded the plant.

Pests

I find the easiest way to get rid of the pot of pests is to soak the pot in a container clear up to the pot’s top. Anything inhabiting the mix will float to the top or drown. The culprits I usually see are sow bugs, earwigs, millipedes, and an occasional slug or two.

Be sure to inspect the leaves, both top and bottom for pests. Be on the lookout for scale, mealy bugs, and spider mites as these are the most common. You can handle these by wiping down the leaves with water and a drop of dish washing soap. After wiping the leaves, I apply insecticidal soap.

To kill two birds with one stone, I mix in a systemic pesticide, like Safari ®, into the water used to get rid of the resident pests. The systemic will continue to help your orchids fend off any sucking pests once they get into the house.

Also, I use this occasion to clean off the exterior of the pot because some pests, mealy bugs in particular, will lay their egg masses outside the pot. I then let the pots drain for a day before bringing them in.

Diseases

Frankly, I haven’t found infections on my orchids; pests seem to be the biggest problem. Having said that, however, it doesn’t hurt to look. If your orchids are outside in the open where it is difficult to control moisture, you might want to look for crown rot. This is treatable with hydrogen peroxide (see reference below).

This is also a good time for prophylactic treatments because there are many pesticide options available than can be applied outside, but not inside. These would be the topical sprays that are absorbed into the leaves of the orchid.  Any spray that is OK for tropical plants will be OK for your orchids.

Summary

When you bring in plants from the outdoors to winter in an indoor growing area, it is important to make sure you do not introduce any pests. While this article deals specifically with orchids, the approaches can be used with any tropical plants. Your mantra must be “An ounce of prevention is worth a pound of cure!”

References:

Cymbidium Orchids - 10 Essentials for Growing Stunning Cymbidiums | Orchid Care Zone

Time to bring houseplants back inside | UMN Extension

Bringing Houseplants Indoors (psu.edu)

What's wrong with my orchid? - American Orchid Society (aos.org)

Orchid Crown Rot - Treatment and Prevention - Orchid Bliss

Photo Credits:  Paul Wood (1,2)