There are many different cell types and sub-types involved in the immune system. Some of the main types include: Lymphocytes: are white cells which circulate between blood and lymph. They play an important role in fighting infection.
After about 50 to 60 days, beets are ready to harvest. Not only can the roots be dug up and chopped to add flavor to a meal, but the greens of the beets can be harvested periodically and put in salads. Given how well these beets fare in different weather conditions, they can be grown several times in a summer.
For succession crop, plantings can be made every 2 weeks to mid-summer. Beets can become tough and stringy if grown in hot weather during droughts; ample water supply is essential to succulent roots. A late summer crop can be sown for fall harvest, start planting them 10 to 12 weeks before the last fall frost.