Ok, so you have these trays/pots of leeks to plant out and you need a decent hole to put them in. Not everyone has a crowbar! Or the strength to make lots of holes. Ooo! Me back! So, try this;
Stout broom handle to which you screw a metal shelf bracket. Push broom into soil and the last bit goes in with foot pressure, a bit of wiggling and there's your hole...Boom, boom! Good for sprouts too....double Boom Boom!