I have an idea that planting tubers so that the eye is pointing DOWN (or at least to the side), will increase the number of eyed tubers that form. The tuber is still, of course, planted approximately horizontal.
This would make no practical difference for most Dahlias which are very generous producers, but the are a few cultivars that are noted for their poor tuber production and low rate of eye formation. Camano Cloud comes to mind. It is such a poor propagator that the originator (Camano Island Dahlias) rarely has any for sale! Except as pot-roots.
This is the type that I propose that WE ALL test in a small experiment next year.
Theory - I have observed that the underground portion of the growing shoot has nodes with scales that would become leaves if exposed to light. Nodes and scales continue to form until the surface is reached and leaves do begin to form. At the base of each scale, therefore, must be some of that all important eye tissue from which next year's eyes will develop as tubers swell from outgrowing roots. It seems to me that more underground stem, with more scales and more eye sites would occur if the shoot had to grow down, then sideways before heading up. More sites = more eyes.
Let's test that!
Report to me when you dig in the Fall and compare the tuber production and I'll compile and post the results.
Several people have done a test or two, but no real records. Oh well . . . .
My own experiment with Camano Cloud is quite definitive. 2 plants each - normal and downpointing eye - planted in a row, alternating.
Normal: one clump = zero usable tubers, other = 1. This is typical.
downpointing: one clump = 2, other 3 tubers. reasonably plump, lots of collar/eye tissue.
Several regular varieties were planted with downpointing eye and gave clumps that were so dense that dividing was a pain, so I don't recommend the practice as a general cultural technique. For problem tuber makers it appears to be the solution - unless you are prepared to get into pot-tuber production.
A friend tells me that this planting method is very common for Caladium growers.
A subsequent experiment seems to indicate that a side pointing eye is just as effective as downpointing.
Copyright © 1996 , 1999 Wayne Holland