Production of Burley tobacco transplants in a greenhouse float system has shown great potential. However, development of spiral roots (negative geotropism) in the float trays results in increased seedling mortality, non-uniform size of transplant and unusable transplants. Experiments were designed to test dibble shape and depth, dibbling and seeding sequences, growth media and media fill of tray cells, seed treatment and growth modifiers on transplant production. Float trays routinely used had 200 cells of inverted pyramidal shape of 2.8 x 2.8 cm at the top and 0.8 x 0.8 cm at the bottom. Pelleted seed, increased growth medium per float tray cell, shallow dibbles and selected medium had poorer germination, more spiral root formation and greater numbers of unusable transplants than other treatments. Growth modifiers tested had no effect on spiral root production. Results indicate the amount of oxygen availability and seed-medium contact are key factors affecting seedling emergence and spiral root development in a greenhouse float system. The conclusions are that 2 to 2.5 g of medium per tray cell, a dome-shaped dibble of 19 mm depth, and a seeding and dibbling sequence to ensure good seed medium contact were best for most satisfactory transplant production.