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.
Dig rows for your beet seeds with a shovel or hoe as soon as you can begin working the ground, or at least 30 days before your last expected frost. Beet seeds germinate in cool weather, so it is the best time to plant them. Rows should be 6 inches wide and the soil should be loosened to a 3-inch depth.