28 March 2023
Asparagus is a perennial vegetable in the lily family, the same as onions, leeks, garlic and other aromatics. Sometimes the group is referred to as “stinking lilies”. White asparagus is the same vegetable only it has been deprived of sun so that the plant does not manufacture chlorophyll, which is the process that turns a plant green.
The plant has three parts, the fern or fluffy top, crown which is located just beneath the surface of the soil, and the roots. Each year, about this time new spears pop up from the crown. To encourage growth, the stems and ferns from the previous year should be removed. You can do this by hand, tilling, or mowing, but use extreme caution to avoid damaging the crowns or you won’t get any spears at all and will probably kill the plant entirely.
Weeds will grow almost anywhere and to remove them from your asparagus patch, the best time is before the spears emerge. After weeding, it is a good time to work in some organic matter. Don’t use any herbicides during harvest time. However, after all the ferns and spears are gone, you can use a product that will not harm the asparagus plants as they begin their regrowth. If you keep the area well mulched, it helps to keep the weeds from spreading and invasive plants from finding a foothold.
These plants like a loose, deep soil that is rich in organic matter. They are tolerant of acidic soil and drought but the ground must drain well. They prefer full sun to part shade. Have a soil test run before planting and adjust the phosphorus and potassium levels if necessary. When you select your spot, be sure it is not prone to frost because that will damage the spears and all your hard work will be lost. Don’t overwater because the plants just won’t like it. However, be aware of dry spells and then water slowly (like with drip irrigation or a soaker hose) so that the moisture will seep down to the roots, where it can be absorbed and used by the whole plant.
It can be affected by crown rot or fusarium wilt. The best way to avoid it is to only plant crowns or seeds that are free of disease. If you have a plant that is becoming ill, remove it immediately along with all of the soil clinging to the roots and around it. Do not put this into your compost heap but throw it in the trash. Otherwise, you will infect healthy plants when you use the diseased compost.
For the best results, purchase crowns that are a year old and are free of any disease. To plant, dig a trench about 8 inches deep and plant the crowns about 18 to 24 inches apart. Then spread the roots and cover with 1 or 2 inches of soil. Plant about a month to six weeks before the average last frost. Don’t cut back the ferns until fall when they will die back naturally. If your patch becomes too plentiful, divide in the early spring.
For high yields, Cornell University recommends all-male hybrids like the Jersey series (Jersey Giant, Jersey King, and Jersey Knight). Flowers on male plants are larger and longer than female plants, so the males will produce larger vegetables. The Jersey series from Rutgers have been developed to resist the fusarium crown rot, root rot, and rust. Their yields have been shown to be two or even three times more productive than open pollinated varieties.