Looking for a maximum of information on growing plants in (or more precisely ON !) a bottle, I first went to Google with a search on “bottle gardening” and discovered that this technical term is also used as a synonym for “terrarium gardening“.
See for instance :
http://ezinearticles.com/?Bottle-Gardening-or-Terrarium—Design-and-Maintenance&id=15811
Bottle Gardening or Terrarium – Design and Maintenance
By Ravikumar Uppaluri 
“Bottle gardening can be taken up in many different shapes and sizes and one can even go for custom made glass containers of the size and shape of choice. But containers of the shape of a normal bottle with narrow neck are the most effective for bottle gardens as it helps in proper maintenance of humidity and also for the appearance when the garden gets established.”
The same idea is developed in :
http://www.hillgardens.com/terrarium.htm
Something Different: Gardening in a Bottle!
by Fred Davis, MG, Hill Gardens of Maine
“ A bottle garden is very much like a miniature greenhouse and, when completed and corked, can be totally self-sufficient under the right conditions. It should go without saying that such an enclosed environment is free of the usual drafts, fumes, variations in temperature and all the other hazards that can otherwise adversely affect houseplants.”
This kind of bottle gardens can be made with glass bottles or even with with plastic bottles, see for instance :
http://www.sip.ie/sip022/b_garden.htm
HOW TO MAKE A BOTTLE GARDEN
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DEFINITIONS ON THE WEB
http://www.boldweb.com/greenweb/glossary.htm
Greenweb’s “Gardening Glossary” is “providing a comprehensive listing of common and uncommon gardening terms“, where one can find :
“BOTTLE GARDEN — A form of terrarium in which a large and heavy glass container such as a carboy is used.”
Emilycompost is also providing a “Garden Glossary” at :
http://www.emilycompost.com/garden_glossary.htm#-%20B%20-
where one finds :
“BOTTLE GARDEN – A small terrarium created in a bottle. A miniature eco-system.”
This is somehow confirmed by Magpie :
http://davesgarden.com/members/Magpye/
“A usually clear enclosure for keeping or raising plants or small animals indoors. Definition as written by Magpye:
Any transparent container with a cover so plants may grow. Sometimes called a bottle garden and in the early 1900’s Victorian era called a Wardian case”.
This is defined by Emilycompost as :
“WARDIAN CASE – In the 19th century a plant explorer and collector by the name of Dr. Nathaniel Ward designed a glass case to transport his findings. He traveled between Australia and England. During the Victorian era often Wardian Cases were highlighted in the home. We now have terrariums and bottle gardens.“
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Thereby it became clear to me that “A bottle garden” (a terrarium) is something quite different from “Bottle gardening“, although literature is mixing the two definitions.
For me, a bottle garden is a miniature garden, set up in a terrarium-like bottle, while bottle gardening is a certain form of container gardening, namely on or inside a bottle (as one of the many materials used for container gardening).
When I am growing vegetables and young trees on plastic bottles, I am convinced to do some “bottle gardening“, although the plants are not growing inside the container filled with potting mix (only the roots do !).
I wonder what your idea is about all this confusing use of the term “bottle gardening“.
Here’s a finished pop bottle pot from in my greenhouse. I have a young alpine strawberry planted in it (click on it for a larger view). It’s sitting in front of some water jugs that were used for thermal storage in my solar greenhouse. I was testing to see if I got better production from warmer or cooler plants.