Planting depth. I have heard 4-6 inches from almost everything I have read. I was looking up how to pot the tubers up ahead of time and now I have encountered new opinions on planting depth. A video from a gardening YouTube channel said “and we leave about 2 inches of soil above the tuber clumps in the pot, just like we do when we plant them out in the field” (something to that effect not word for word). Then I search more on this and found this from Brent and Becky’s (the bulb website) “While many bulbs are planted at a regular depth of 3-4 inches deep, dahlias should only be buried deep enough that the old stem is right at soil level. The tuberous root cluster should be buried, but the old stem should be sticking out - as that is where it will sprout from.”
Then I remembered my neighbor gave me an old hand out on growing dahlias from many years ago. It was interesting to read the growing advice/techniques vs what you hear now. For example it listed off several different pesticides to spray at such and such intervals (not something you see when buying tubers these days). Another thing it said “for earlier blooms you plant them more shallow and then fill it in as it grows” something to that effect. So now I am thinking of playing with the idea of going shallow this year for some plantings. Anyone regularly do a shallow planting? If so is this only or for tuber clumps or can it apply to single tubers? I’m guessing the soil temp is warmer/warms up faster the closer to the surface which causes quicker sprouting and growth.
