I would like to experiment this season with the 'Swan Island' technique of support...or 'non-support' as it were....on at least some of my dahlias. Extra deep planting; hill up soil as plant grows like I do for potatoes; trim off entire dahlia plant once it reaches, say, 3 feet; hope for the best! But since I start my dahlias in a greenhouse and transplant potted plants that are 8 inches to 14 inches tall, can I bury those plant stalks deeper than the soil level in the pots? Can I bury them 4 inches deeper....6 inches deeper? Any threat of stalks rotting? Thanks!

I would thinking planting them extra deep could create some challenges since they won't be above the ground as soon as they could be. Rain/water has a higher chance of impacting them. Experimenting is usually not a bad thing.

You can bury the tuber and growing stalk.

you can bury the stalks.. in fact they will grow roots and eventually tubers and crowns where you pinched off leaves..
how deep is really dependent on drainage... if you have heavy clay soil deeper will be wetter.. but that's really the only limitating factor

don't forget digging them up... going deeper will make digging them more work.

cmcramer said: I would like to experiment this season with the 'Swan Island' technique of support...or 'non-support' as it were....on at least some of my dahlias. Extra deep planting; hill up soil as plant grows like I do for potatoes; trim off entire dahlia plant once it reaches, say, 3 feet; hope for the best! But since I start my dahlias in a greenhouse and transplant potted plants that are 8 inches to 14 inches tall, can I bury those plant stalks deeper than the soil level in the pots? Can I bury them 4 inches deeper....6 inches deeper? Any threat of stalks rotting? Thanks!

Is this method used so you don't have to stake the plants?

cmcramer said: I would like to experiment this season with the 'Swan Island' technique of support...or 'non-support' as it were....on at least some of my dahlias. Extra deep planting; hill up soil as plant grows like I do for potatoes; trim off entire dahlia plant once it reaches, say, 3 feet; hope for the best! But since I start my dahlias in a greenhouse and transplant potted plants that are 8 inches to 14 inches tall, can I bury those plant stalks deeper than the soil level in the pots? Can I bury them 4 inches deeper....6 inches deeper? Any threat of stalks rotting? Thanks!

The type of soil is an important variable when using this method. Swan Island has a light, sandy soil with good drainage.
Wait to start hilling until after the soil warms up. If you bury the tubers/plants too deep early in the season (when the soil is cold) the growth will be slow.
Conversely, don't mound hot soil around tender stalks or the stalks will rot and the plants will not be happy.
Experiment with a few plants to see what works best under your conditions!