It's generally easier to grow in a taller container because the PWT will be the same height in all containers if using the same soil. So, taller containers will have a higher percentage of unsaturated soil when at container capacity. (Container capacity is a term usually used in commercial container culture that describes the state of the soil immediately after watering and when the container has just stopped draining.) However, proper wicking technique goes a long way toward eliminating problems associated with a shallow container. As soils become finer, holding more water and less air, problems with growing in shallow containers become more likely to affect root and thus o/a plant health.

When using soils that drain well, container volume would be a more important consideration than ratio of height:width. As long as you're aware of how shallow vs. deeper containers affect the PWT, good soils allow you to easily make adjustments.

Al

Thank you Al,

I am looking at buying some pots for next year. I knew that the PWT is a factor to consider, but wasn't sure if there were any advantages to a wider/lower pot assuming PWT was greatly reduced or eliminated.

I guess I could have posed the question as to which way the roots tend to grow more... out to the side or downward.

~james

The primary determining factor about where roots prefer to grow is aeration. Those plants (growing in situ) with roots growing at or immediately below the surface prefer a highly aerated medium. Since container soils need to be better aerated than in situ soils, it's a non issue. Roots of plants in containers, even shallow rooted genera like Acer & Rhododendron will readily colonize the entire container as long as there is air in the soil.

Al

Thanks again, Al.

This makes perfect sense.

~james