Buy large flowering sized bulbs. I have Lycoris aurea and I'm finding them painfully slow to man up. Here is the Pacific Bulb Society Lycoris page.
Found these on ebay @longk http://www.ebay.co.uk/itm/161281506364?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 I think by reading that link they need a lot of patience
Found these.................... http://www.ebay.co.uk/itm/Lycoris-r...arden_PlantsSeedsBulbs_JN&hash=item1c3f4fc84e http://www.ebay.co.uk/itm/Lycoris-a...arden_PlantsSeedsBulbs_JN&hash=item19ebb4b9cb I've used them before and been happy.
They are on my "Stop drooling over them and move on to something else" list along with this comment, in case helpful? "never been very successful outdoors in the UK. Need a hot summer bake and to be "woken" by the first rains of autumn. Then they flower in September. They are less hardy than, say, Nerine bowdenii. Perhaps I should be prepared to lift Lycoris radiata during the Summer and put them in a box in greenhouse??"
Not so much grow as bake the bulbs. Plenty of water from above when you put the pot out too I think is your best chance of success.