this what i found about air pruning...this has been used for years by many gardening centers to keep plants that they sell have a longer shelf live in smaller containers...and make it easier to transplant after purchase......
An air-pruning propagation system is a low-cost, efficient method of propagating cuttings, seedlings or container plants for restoration projects. Air pruning happens naturally when roots are exposed to air in the absence of high humidity. The roots are effectively “burned” off, causing the plant to constantly produce new and healthy branching roots. If roots are not exposed to air, they continue to grow around the container in a constricted pattern. The roots may spiral, twist, kink or become strangled. When the plant is later installed it will likely fail to establish a normal root structure, and instead will have reduced uptake of water and nutrients. Eventually abnormal growth should be obvious and could cause the plant to fail. Damaged root systems also cause leaves to turn yellow or brown, shrivel or drop. Healthy, highly branched root structures allow a plant to more efficiently uptake water and nutrients while increasing growth and overall plant health. A strong root system will make a plant better able to establish itself when installed in a restoration project.
Advantages of air-pruning:
· promotes branched root systems
· encourages new roots to sprout
· prevents roots from spiraling
· prevents plants from becoming pot-bound
· plants may remain in pots, plugs or plant bands longer
almost all of my party cups has done the twist....the whole bottom of my cup has roots that just circle the bottom...so ill be doing it this way from now on for any plants i plan to transplant out of the party cups...hell it probably wouldnt be a bad idea on those that dont get transplanted also