Under glass
Gladioli will flower earlier if sprouted in a greenhouse. Place single layers of corms in trays in a temperature of 10ºC (50ºF). The trays must be placed in full light. Watch for signs of aphids on the sprouts, which will soon appear, and dust the corms promptly with BHC if pests are seen. Plant the sprouted corms, 4-5 in. deep in colonies or in rows 12-15 in. apart.
  Check stored corms and discard any that are diseased.
  If ground has not been prepared for gladiolus planting, this must be done at the first opportunity.