Warmth - it's been a cold spring. I germinated mine in a propagator in a poytunnel to get the warmth. Try a warm windowsill indoors - it's not too late.

Oh, and try a new packet of seeds... just in case you got a ropey batch.

Hi, welcome to GoY, agree with the above, but it could also be the activities of the bean seed fly, {larvae}which live in the soil, and attack emerging seedlings, they're active from april, but most active during may, Derek.

Yes its a good idea to sow indoors in a deep container. Toilet roll middles of large yogurt pots are useful for this.

If sown direct in ground it may be meeces!!!