With their mild but pungent onion flavor and bright color, red onions (Allium cepa var.) are ideal for adding to all types of salads. Some varieties are excellent for storage, keeping their quality through the winter months. Red varieties of bunching onions are available as well, including a perennial clump-forming type.
A flattened globe-type onion, red Whethersfield (Allium cepa "Red Whethersfield") is an old variety. Suitable for growth in the north, it is a long-day onion and will fully mature in 110 to 115 days. It is an excellent keeper for long-term storage. Sow seeds in early spring and thin to stand 4- to 6-inches apart when the seedlings are 3-inches high.
Maturing in 100 days, the red onion mars (A. cepa "Mars") is a long-day onion suitable for growing in the north. Seeds planted in early spring should be thinned to stand 8- to 10-inches apart when they are about 4-inches high. Mars onion requires fertile, well-drained soil and a lot of moisture to grow to its full mature size of up to 8 inches in diameter. Their top growth often reaches 3-feet high. Harvest after the tops die down in early fall. Their flavor is sweet when freshly picked but becomes more pungent in storage. Mars will keep 4 to 6 months if properly stored.
Welsh Red Stem
Welsh Red Stem (A. fistulosum "Welsh Red Stem") is a perennial bunching onion native to Siberia. Start them from seed in early spring in fertile, well-drained soil and thin to about 3- to 4-inches apart when the seedlings are about 3-inches high. They form a clump of slender onions from each seed which will grow in size every year. Lift and divide every three to four years.