Asparagus (Asparagus officinalis)
A native perennial to the Mediterranean and cultivated for many centuries, a well planned asparagus bed will deliver tasty delicacies for decades. Rarely considered is the beauty of the mature plants with a lacy fern-like structure which develops after the harvest has ended for the season. While inedible, delicate red berries arrive on the female plants in the fall for a pop of late season color. Unless you can flash freeze asparagus, this is one vegetable to be enjoyed when it is fresh, and then eagerly awaited next season.
Nutrients: dietary fiber, vitamins C, K, B6, and A, magnesium, calcium, phosphorus, iron and zinc.
How to Grow Asparagus from Seed
Asparagus is a cold-hardy perennial that can be grown either from seed or crowns. Asparagus tolerates full sun to partial shade and prefers moist, well-drained soil. If planting crowns, dig well cultivated trenches 12” wide, 6-8”deep, and 24” apart. During the growing season, side dress plants with an organic nitrogen fertilizer such as manure, fish emulsion, blood meal, etc. Asparagus does not like weed competition, so keep beds weed-free throughout the growing season.
In spring or fall, place crowns in trenches and cover with 2” of rich soil mixed with compost. As plants begin to grow, continue covering 1/3 of the plant at a time with soil until the trench is filled.
Start seeds indoors 12-14 weeks before the last frost date. Seed germination rates can be improved by exposing seeds to cold, moist temperatures for 4-6 weeks prior to planting (cold stratification). Cold stratification can be done inside a refrigerator. Sow seeds 1/2” deep and 4-6” apart. Seeds will sprout in 10-53 days. Thin seedlings so that mature plants are 12" apart. Transplant seedlings outdoors once the danger of frost has passed.
In order to allow asparagus to become well established, do not harvest for a year if grown from crowns and 3 years if grown from seed. For the first year of harvesting, gather spears for 2-3 weeks before allowing the fern-like foliage to grow. For each year asparagus has been in your garden, add another 1-2 weeks of harvesting until you reach 8 weeks total. Snap off spears rather than cutting them to reduce the incidence of disease.
How to Save Asparagus Seeds
Asparagus is dioecious, meaning that separate male and female flowers occur on different plants. Only female plants will produce the red fleshy fruits, each containing about 5 seeds. Most gardeners grow asparagus from 1-2 year old crowns and if you do not need seeds, it is advised to not allow plants to set seed because it takes energy away from vegetative growth.
If you do want to try your hand at growing asparagus from seed, the fruits will mature in late summer/fall. Allow fruits to turn red and soften before collecting seed. Remove fleshy coating, rinse seeds and dry thoroughly before storing in a cool, dry place. Seeds will remain viable for up to 3 years.