Greenhouse Canada

Features Handling Systems Structures & Equipment
Inside View: July 2011

June 20, 2011  By Gary Jones

The humble “flower pot” is now so much more than just that.

The humble “flower pot” is now so much more than just that. What used to be a simple fired-clay terracotta (literally “baked earth”) container is now a “multi-function device.” It’s like comparing a wrist watch (that us “more seasoned” folk) used to tell the time, to today’s cellphones (that the young ’uns) use to tell the time, text, call (occasionally!), take pictures, do math (really?), set their schedule, watch movies, and so much more.

Discussions around pots these days include many factors:

  • What are they made of (terracotta, plastic, coir husk, rice husk, paper or corn starch, to name a few)?
  • What’s the appropriate pot size for a particular plant?
  • What colour is it? Pots make great advertising and promotional space, have become trademarks and even form showpieces in the “outdoor room” if high-end decorative pots are chosen.
  • Can it hold more than one plant? Plastic packs with multiple, different sized cells and labels that form handles are just great for marketing everything needed for a hanging basket in one “grab-and-dash” unit.
  • Is it good for the planet? Plastic versus terracotta? Check out How Bad Are Bananas? The Carbon Footprint of Everything, a new book by Mike Berners-Lee, published May 20 (Profile Books).

■ Even such diversity doesn’t stop new pot transformations from appearing regularly.

The patented Smart Pot™ is a soft-sided, fabric container originally developed for and used by commercial tree growers for about 20 years. It has some rigidity to hold its shape and is often seen used for container production of large trees. The Smart Pot is “an aeration container.”

According to the manufacturer’s website (, it “has a unique ability to air-prune and enhance a plant’s root structure.”

The thinking behind this is that a plant with more roots is likely better able to withstand tough times – drought, drowning, poor growing medium, and so on.

High Caliper Growing, maker of the Smart Pot, has been around since 1984, but actually began six years earlier as The Tree Farm in Guthrie, Oklahoma.

Owner Ralph Reiger was having problems finding people who could dig trees ball and burlap. He eventually developed the first fabric containers (Root Control Bags) and started selling them in 1980.

During the first year’s production, Reiger realized the fabric “Root Control Bag” had root-pruned the plant’s root structure, giving improved plant growth. These “pots” immediately gained the attention of a number of progressive nurserymen, and have gained thousands of customers growing millions of plants in all 50 U.S. states and elsewhere worldwide.

■ More recently, another “root pruning pot” has arrived. The Superoots “Air-Pots” from the Caledonian Tree Company in Scotland have unusual “cuspated” walls. They look like skinny, narrow egg boxes laid on their sides, but are actually made up of closed, inward pointing cones and open-ended outward pointing cones.

According to the website (, “there are no flat surfaces on the inside of the pot. The inward pointing cones direct the roots outward to the open-ended cones where, because the air density in the soil is too great, the roots dehydrate and are effectively pruned. The plant responds to this “air-pruning” by sending out more roots to compensate for the loss, which leads to a dense root system with a vast number of active, white-tipped roots.

“The porosity of the Air-Pot also creates better conditions for bacterial activity and thus increases the amount of nutrient available to the plant. With so much root right back to the stem, the root system is very efficient in its use of all the available water and nutrient.”

Superoots Air Pots are made of recycled HDPE, can be made to any diameter in a variety of heights, and can be used as pots complete with or without a base.

So, next time you place an order for pots, perhaps you need to stop and think. Maybe you should be asking for a one-gallon, free-draining, air-pruning device that complements your pastel yellow outdoor garden furniture and is made from fully recyclable environmentally friendly, locally grown, corn starch.

Gary Jones is chair of production horticulture at Kwantlen University, Langley, B.C. He serves on several industry committees and would welcome comments at

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