Q and A: Quarantine for Large Plants

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Reader CJ left a couple questions in the comments of my post about keeping new plants in quarantine before adding them to a terrarium.  I'm sharing a version of my reply in this post to clarify the circumstances for which I recommend the quarantine process for terrarium plants.

Q: I recently decided to attempt a trio of open terrariums in my home. I bought a variety of different plants including irish moss, davalia trichomanoides (fern), hypoestes phyllostachya, and what I suspect to be a peperomia scanden (unlabeled), along with 2 other unlabeled plants from a local nursery. I am also buying a small orchid. I want to take the proper steps before beginning the process of planting them all. How do you quarantine medium sized plants? They range in height from about 3" to 10". Should they be separate from one another? 

A: If your open terrarium vessels are large enough to reach your hand into - I wouldn't worry about keeping them in quarantine prior to planting them.  If mold develops you can reach in and cut it out or scoop it out as it develops and a larger vessel isn't as likely to get quickly overrun by bugs or mold.  To recap my suggestion from the original post:

It is relatively easy to remove problem items from a large-opening terrarium such as a vase, fishbowl or dish.  But if you aim to plant a terrarium in an enclosed terrarium or a narrow-opening vessel like a wine bottle, test tube etc. it may save you time an energy in the long run if you can be patient enough to "quarantine" your plants and moss to see if any problems surface before you add them to your terrarium.

If you'd still like to quarantine your larger plants prior to planting them, you may be looking at a need for additional equipment.  Some terrarium enthusiasts invest in large aquariums or wardian cases in which they can enclose their plants prior to terrarium-planting.  You can keep several new plants in the quarantine vessel for a period of time.  Make sure to inspect each plant regularly for insects or mold and remove promptly if discovered so they don't contaminate each other.

Smaller plants can be sealed into a gallon ziplock bag, kept upright with a chopstick or popsicle stick as a stake.  Make sure to leave the bag slightly "unzipped" to allow for airflow.  Don't leave your plants in bags for longer than three days or so.