I had radishes come up in all my beds; the extremely fertile beds and the alkaline sandy beds. The only time, for me, they aren't as successful is when they don't get full sun. Is that your problem, since they are interspersed with some tall neighbors?

RE: your peppermint... get it out of there before it takes over!

Concur; It could be lack of light, they need full sun. I would also be suspiciuos of the peat moss. It may be too acidic for radishes.

Radishes are funny critters. They will germinate awesome, but how they grow is a coin flip. I was never able to grow decent radishes......too leggy. But the soil at my wife's home was perfect. She just throws seeds in the ground and gets perfect radishes. A friend of mine used to grow them big as beets.

Thanks all. The taller plants are to the north and west of the radishes. The strawberries are east and south; they are starting to sprawl but they are not over-shadowing the radishes. I have observed the bed at different hours of the day and see no real shade over their location.

May be the peat moss is it. The other bed where the radish did ok is just a mix of various materials. I think the bed contains bagged compost, bagged "garden soil", some wood ash from fireplace, potting soils from abandoned containers, and possible others.

I know the peppermint is going to be an issue, but so is my 7 year-old daughter when I take it out. I am going to make do until I get her a small bed put together for just her choices.