Check with your state's Extension Service. Each county should have it's own Cooperative Extension Office which provides free publications and information for the asking. They can also tell you the average last frost date for your area and ideal planting times for specific crops and varieties in your area.

The following two images are excerpts from the Vegetable Planting and Planning Calendar for Missouri (download the pdf complete with spring and fall planting dates, how much to plant per person, etc. Just call up the office in your county. Look under the "Government" section (usually blue pages) of your phone book under "Extension". They will have valuable vegetable/gardening tables available specifically for your area from data they've collected from growing those crops in your state.

Violet

hope you don't plow them under because radish leaves are delicious! just dice and add salt,leave a few days in fridge and you've got a great side dish,

or you can add soy sauce, diced garlic, red pepper, let sit a few days in refrigerator, and you've got another great side dish...

1. Excessive nitrogen fertilizer.

2. Not enough hours of sun.

3. Magnesium deficiency.

4. Not a steady supply of moisture.

Sandy soil should work well, except it is more difficult to maintain the correct levels of nutrients and moisture. A little epsom salts will cure a magnesium deficiency.

If anyone knows of a watermelon type radish that can be sown in spring or any time of year, I would be interested.

I'd also be cautious of guessing about adding things like epsom salts. It may be a short term solution and make you feel better but for optimum results,
contact the Nova Scotia Dept. of Agriculture and ask them where you can have your soil tested. The results will show you exactly what you need to do to amend your soil. Testing in my state was less than $12 and results lasts three to five years. Completely worth it. No guessing, no buying and adding things you don't need and wasting money you don't have to.

The most important issue as mentioned above for root crops such as radishes is consistent moisture and cool temps. Again, sandy soil is only good if you have ammended it with peat so that the peat keeps moisture so that is is readily available to the plant. Only sand will not work because water will drain out of the sand so moisture will not be constantly available for the plant.

More info:
http://www.urbanext.uiuc.edu/veggies/radish1.html

http://forums2.gardenweb.com/forums/load/frugal/msg0323332415768.html

Thanks for letting us know the results of your radish growing. It's very nice to hear that you succeeded and what you believe to be the solution. I have grown them with mixed results, sometimes terrific, sometimes lousy. I'm hoping for great crops this year. I enjoy eating radishes.

Jim

There are some other huge daikon radishes, too, also interesting. I love radishes!

"Podding"? Are you meaning for transplanting? If yes, don't get them. It is best not to transplant any root crop like radishes, carrots, parsnips, etc. Always start from seed. Put them where you want them and don't move them.