impossible, very not recommended. but i can't get them to sprout in a bed. i started two different types in those bonsai pots, 2" deep, 5" diameter with half potting soil, half sand, and they sprouted fine. got about an inch tall and started to falter, so tonight i transplanted them to a much larger container with the same mix. procedure: a good pair of forceps a pencil good eyesight something that will drop individual drops of water (sriracha bottle) you want the seedlings to be almost dry, so the soil is crumbly. delicately rake the open forceps through the soil to bring up the ridiculously long tap root - finer than a hair, about 3 inches long. use the pencil to make a 4" hole in the new soil. grasp the seedling by the end of the taproot and pull it down into the hole, the collapse the hole. drop a few drops of water around the seedling. repeat. when you are done, mist or shower the seedlings as gently as possible, but get a good soak in. i was chasing daylight as i finished, so they get the cool night in to recover. back tomorrow with the casualty count.
You're very brave. I grow a lot of poppies, and they're notorious for not liking to be moved. I hope you don't mind if I make a suggestion. If you absolutely can't sow them in place, then I would sow them in either little peat pots or (clean) eggshells, then when it's time to plant them just pierce the bottoms and plant the whole thing.
it worked fine - about 90% survival. mind you, i carefully pulled up every taproot and replanted it one by one, with three drops of water, then kept it misted for two days, but they're off and growing now.