Radishes are ready to pick around 25 days after being planted. If they are have been thinned they will produced a deliciously spicy bulb. You can check their size by gently sticking your finger in the soil and if you like their size, go ahead and pick them. Radishes can be reseeded in the fall for another radish harvest.
Carrots and beets
If planted in the spring, beets and carrots are ready to harvest end of July and beginning of August. A good way to know is to investigate the size of the root with your finger in the soil, if they are large enough to your taste, pull them up. Continue to harvest them as needed.
Carrot tops have a taste reminiscent of parsley and can be eaten raw in the salads, sautéd in garlic, olive oil along with your beet tops, kale and swiss chard. You can also cook carrot greens into à soup or a stock.
Beet greens taste a bit like beets and swiss chard. Harvest them as you need them and remember that beet greens are delicious in a sauté, in a quiche or raw salad.