Nicholas dahlia tubers. We have more than 100 varieties and increasing our inventory, if interested PM and will send you list and prices. Dahlia Care: Start your tubers early in a pot indoors and do not water until roots and sprouts have established (rot can occur otherwise). You can also directly plant (4-6" depth) in the garden after temps have risen to 60°. Dahlias need full sun, staking support, good air flow (remove spent lower leaves & space 12-18" apart) and benefit from pinching when 12" tall and 4 sets of leaves are present. A fertilizer with a higher phosphorus and potassium ratio (i.e. 5-10-10) will encourage endless blooms.