Why didn't the radishes I planted grow into full sized radishes?

Question:I planted them from seeds directly in the ground .Their leaves grew nice and healthy and the radishes didn't,they even went to seed.This is my first time growing them.I have luck at everything else.My boyfriend is the one who eats them,so I left it to him to care for them,and he didn't seperate the seedlings as was told to do on the package,after they grew to a certain height.Could that have been the problem?

Answers:
I grew carrots once that had all tops and no bottoms and I was told by the nursery that it was because the soil was too hard, that it had too much shale and the mud looked fine and soupy when wet but when dry it hardened and wouldn't let the plants grow. So I would say that you need a lighter soil. When you go to plant I'd suggest you dig out a section where you want to plant and then add things to it like vermiculite and some mulch. Give a call to your county's agriculture department and ask what else. Maybe they will suggest some lime. And bags of soil from the nursery. I alos wondered what you were feeding them, or if you were feeding them. If you feed them flower food you will get tops, if you feed them vegetable food you will get food.