You can start them off in pots inside now - don't put outside into final positions until end of May.

Yes, just snuggle them down in the compost and don't completely cover them with compost until they are growing well ,or they may rot. Just water around the tuber (bulb) as they may rot if water settles in the dip in the middle. This dip is also a clue to the right way up to pot them, in case they don't have a little pink bud showing in the middle.

I planted my begonia tubers half an inch deep in compost filled pots in mid February 2011. Put them on a windowsill and keep the compost just moist.Last week of March 2011 and first signs of life are just appearing! I was told not to feed them until they are 3 inches high, so will just keep the compost moist till then. At least they're growing !! ( albeit very slowly - but at least they're trying ) Yours may come on a bit faster planting them a bit later when everythings a bit warmer..........