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.
When to Plant. Begin planting beet seeds directly in the garden one month before your last spring frost date, followed by a second planting two to three weeks later. Beet seeds can germinate in cool soil, but they sprout best when soil temperatures are above 50 degrees Fahrenheit.Start planting beets for fall harvest 10 to 12 weeks before your expected first fall frost.(Learn more about your regionâs planting dates by using our What to Plant Now pages .).eet seeds can germinate in cool soil, but they sprout best when soil temperatures are above 50 degrees Fahrenheit. Start planting beets for fall harvest 10 to 12 weeks before your expected first fall frost. (Learn more about your regionâs planting dates by using our What to Plant Now pages .).