Planting Guide and Seed Saving notes for Broccoli
Broccoli (Brassica oleracea)
Introduced in the United States by Italian Immigrants, it oddly did not gain popularity until the 1920's. While today it is well known for its tasty unopened flower heads, the entire broccoli plant deserves praise and a place in the kitchen. The florets and stalk can be roasted in a very hot oven to bring out an often-unknown sweetness, or steamed, sautéed, and enjoyed raw. But, broccoli should always be served bright green and al dente, never overcooked to keep nutrients at their highest levels. The leaves make an excellent cooking green, prepared in the same way as collards.
Nutrients: dietary fiber, vitamins C and K, potassium, folate, beta-carotene and the phytochemical quercitin.
How to start Broccoli from Seed
Broccoli is a moderately frost tolerant biennial that prefers full sun, although it will tolerate light shade. Plant broccoli in well-drained soil that is high in organic matter. Avoid applying too much nitrogen which can lead to hollow stems.
Broccoli seed can be started indoors 4-6 weeks before the last frost in spring or in mid-late summer for a fall crop. Transplant seedlings outdoors when plants have 3-4 true leaves. Seeds can also be direct seeded outdoors and will germinate at soil temps as low as 40˚ F, with ideal temperatures being 50-80˚ F.
Sow seeds 1/2" deep and 2-4” apart. Seeds will sprout in 5-17 days. Thin seedlings so that mature plants are 18-24" apart.
Broccoli is harvested as an immature flower head, so cut heads before the yellow florets start to open. Depending on the variety, this will be 60-90 days after planting. To harvest, cut just below the point where the stems begin to separate. Generally, tender edible shoots will also form in the leaf axils. Keep cutting for multiple harvests.
How to save Broccoli Seed
Broccoli needs milder winter conditions in order to flower. Isolate seed plants from other Brassica oleracea that may be in flower at the same time. Do not harvest the heads of your seed plants, although one method is to cut the central head and let the side shoots go to seed. Most broccoli plants are self-sterile. Plant at least 6 different plants to protect vigor and ensure a reasonable amount of genetic diversity. Seed stalks are 4" long and produce a lovely yellow flower. Allow individual pods to dry to a light brown color before picking and opening by hand. Lower pods dry first followed by those progressively higher on the plant. Smash unopened pods in cloth bag with mallet or by walking on them. Winnow chaff and dry.