Asparagus, touted on some lists as a superfood, is low in calories and carbohydrates and rich in vitamins and minerals. Compared to other vegetables, it is relatively rich in protein. Asparagus is an excellent source of potassium, vitamins A, C and K, riboflavin, thiamine, folic acid and vitamin B6. Asparagus is also a very good source of dietary fiber, niacin, phosphorus, and iron and suitable for use in low-sodium diets.
Asparagus boasts both anti-oxidant and anti-inflammatory agents as well as having antifungal and antiviral properties. There are even claims that asparagus fights hair loss, varicose veins, high blood pressure and kidney stones.
Asparagus is in the lily family along with onions, leeks and garlic. It is a perennial vegetable, with individual plants lasting 10 -20 years. The mature plant looks like a small shrub with lacy, fern-like foliage. Seed can be sown in 4 inch pots and be ready for transplant within 3 months. A quicker method of establishing plants is to order 1-2 year old crowns from a Mainland nursery. Mary Washington is a common variety sold, but some newer California varieties such as Apollo, Atlas and UC 157 seem to be more suited for Hawaii’s climates.
Asparagus prefers a sunny location with well-drained soil. It will not grow well in an extremely acidic soil (about pH 5.9 or less). Since asparagus does not compete well with weeds, diligent weed control is a major task.
In areas where summers are dry and warm, like California, asparagus ferns begin turning yellow during the hot summer and will eventually die back. Then, in the beginning of the year, the roots, actually the crown, will send forth numerous asparagus spears. These are what we harvest and eat. If left to grow, they will become the tall, fern like leaves.
In warm, wet climates like Hawaii, the ferns do not die back and the plants grow all year around. One method of harvesting is to cut down the entire fern plant. Then, for approximately 4-6 weeks, harvest the subsequent spears that emerge. After this time, allow the spears to grow into ferns. These will replenish the crown. Then, after 5-6 months start the procedure all over again. If you have enough plants, the procedure can be staggered to allow for year around harvesting. An alternative method is to harvest newly emerging spears from a fully bushed plant. But at some point it is best to cut the existing fern.
When harvesting asparagus, it’s important to keep in mind that the green ferns (leaves) replenish the crown with starches (energy for the plant). Continuous harvesting will deplete the crown of starch, and the plant will produce poorly and even die. After a period of harvesting, the plant must be allowed to grow in order to replenish the starches lost in harvest. In fact, newly planted asparagus should not be picked for at least one year and preferably two, in order to build a healthy crown. For more on harvest methods and other aspects of growing asparagus, check out the University of Hawaii CTAHR publication entitled, “Asparagus.”
On the Big Island of Hawaii, asparagus plants are relatively pest free.
The following nurseries carry one or more of the California varieties Apollo, Atlas and UC157, either seed or crowns.
1. West Coast Seeds – website: www.westcoastseeds.com; 888 804-8820.
2. Cutter Asparagus Seeds, Arbuckle, CA – website: www.asparagusseed.com Tel 530 476-3647
3. Seeds of Change – website: www.seedsofchange.com
4. Reimer Seeds, North Carolina – website: www.reimerseeds.com
5. Pendleton’s Asparagus Crown - Lawrence, Kansas. Email at email@example.com; website – pendletons.com; Tel. 785 843-1409 . Does not ship to Hawaii.
6. California Asparagus Seed and Transplants, Inc – website: www.calif-asparagus-seed.com Tel. 530 753-2437 Seeds only, minimum order.