Colanders for deciduous trees too?

(Les Lonsdale) #1

I read a lot about using colanders for better root growth for pines, but what about for other trees. Would they also benefit the same way? Should ALL younger trees be started in colanders?

(Frank Corrigan) #2

It is possible to use colandars on deciduous trees. I use them on young maples for a short period of time. Approximately two years. i would not use the word “should” because there are lots of alternatives depending on your objective for the tree. Colandars are simply one version of container that can be used to air prune roots or begin to create a certain shape of root ball. For example if your goal is to produce more of a plate shaped nebari root ball then the colandar would not be appropriate. In that case you would likely choose a flatter and wider container to create thicker longer roots extended straight out. Possibly screwing the base to a board or threading the seedling through a hole drilled in a tile. There are some negatives to the use of colandars as well. Stability , additional watering frequency are two of those idiosyncracies.

(Les Lonsdale) #3

Thank you Frank, for a well thought-out answer and for offering the other options! Appreciate it!

I did an experiment with 3" ‘air-pots’ last year, using young plants (maples, junipers, elms), with one in an air pot and a similar plant in a plastic pot. After one year, the plants in the plastic pots all had a much more extensive root system. The only reason that I could think of for the unexpected results, was that I used a fast-draining bonsai mix in both pots, so I think that the air-pots stayed too dry.

I am repeating the experiment again this year but using normal potting soil in the air pots since they drain so well anyway.


(Frank Corrigan) #4

Your welcome. That is a good observation on your part regarding the drier mix in colandars. I believe the key to this whole combination of container and soil mix is understanding how to use the varying combinations to suit our objectives. Then adjusting our daily care to suit the methods we employ.
For my purposes, the colandar allows me to pot trees in a better quality inorganic soil mix for root ball formation and allow some of the roots to escape into grow beds with a higher organic mix for even temperature , additional nutrient supply and longer term moisture content. I do not use them for air pruning.