Some more "Words of wisdom" about Radishes. I posted about these a few days ago, but I just wanted to help beginners with some of the important aspects of growing them. Here's one such beginner taking a close interest in the subject...
Ideally, Radishes should be grown very rapidly (they can be ready in about a month from sowing), which means putting them in full sun, but also providing them with lots of water. I find that at the slightest excuse (lack of water being the most prevalent) they will bolt. A bolting plant puts all its energy into a tall, thick woody stem - which will produce flowers, soon followed by seed-pods, like this:
The red part will be tough, fibrous and probably very peppery - most unattractive! Sometimes you don't get a "bulb" bit at all, only stem - like this:
On the other hand, if you are meticulous with watering, this is what you can get - crisp, succulent, spicy yet sweet at the same time:
Notice: no visible stems at all; the leaves seem to grow directly out of the top of the red "bulb" bit.
The soil in my garden is very sandy, and dries out quickly, so not really ideal for growing radishes, but if you are prepared to put in the effort you can grow radishes practically anywhere. I do have to admit though that I have never been successful with growing them in containers, in which they ought to do well.
Another thing to be careful with is to sow the seeds thinly (maybe an inch apart), or failing that, thin them out soon after they germinate. If they are overcrowded they will compete with each other for the available light and moisture and will be very likely to bolt before producing any worthwhile crop.
Hope this is helpful! Radishes are often touted as a beginner's veg, but unless they are given the right treatment, they can easily disappoint.