Asparagus (Asparagus officinalis) is a long-lived perennial vegetable prized for its tender spring spears. It can produce a harvest for 15 to 20 years once established. While the idea of propagating this vegetable easily from a cutting is appealing, asparagus cannot be grown from a spear placed in water. The edible spear is merely the young shoot of the plant, lacking the specialized tissue structure necessary to develop a new, independent root system.
Why Asparagus Cannot Grow From Cuttings
The edible portion, the spear, is a modified stem or shoot that emerges from the ground. This shoot is designed for upward growth and photosynthesis, not for generating roots.
Asparagus requires an underground structure called the crown, which is a fleshy, thickened rhizome. The crown contains the meristematic tissue where cell division occurs, storing energy and originating new growth buds. A detached spear lacks this vital reproductive base, meaning it cannot produce the storage roots that sustain the plant long-term. Attempting to root a spear in water will only result in the cutting rotting.
The Preferred Method: Planting Asparagus Crowns
Planting one- or two-year-old dormant root masses, commonly known as crowns, is the preferred method. Crowns are a mature root system with established growth buds, putting the gardener ahead by a year compared to starting from seed. Planting typically occurs in the early spring as soon as the soil is workable.
A trench 12 to 18 inches wide and 6 to 12 inches deep is recommended; a deeper trench is better for sandy soil. Within the trench, form small mounds of soil, spacing them 12 to 18 inches apart down the center. Each crown is then placed on top of a mound, carefully spreading the fleshy roots so the growth buds face upward.
The initial covering of soil should only be about two to three inches deep over the crown. As the new shoots begin to grow and reach several inches in height, more soil is gradually added to the trench over the course of the first growing season. This slow filling of the trench encourages the development of a strong, deep root system and prevents the crown from being buried too deeply at once.
Growing Asparagus From Seed
Growing asparagus from seed is a viable alternative, though it demands more patience. This method requires an additional year of waiting before the first harvest compared to planting crowns. Seeds are best started indoors, generally 10 to 12 weeks before the last expected spring frost, to ensure a strong start.
To encourage germination, soaking the seeds before planting is beneficial. Seeds should be sown about a half-inch deep in a sterile seed-starting mix and kept warm, ideally with a soil temperature between 70°F and 85°F. Once the danger of frost has passed, the seedlings (now small crowns) can be transplanted into a temporary nursery bed or directly into their permanent location.
Essential Care and Harvest Timeline
The first two to three years of an asparagus patch are dedicated entirely to root establishment. Weed control is particularly important during this time, as the plants are poor competitors, so shallow hoeing or hand-pulling weeds is necessary to avoid damaging the shallow roots. Consistent watering is also required, especially during the first year, to help the crowns become fully established.
The key to a long-lasting, productive patch is patience with the harvest timeline. No spears should be harvested during the first growing season, allowing all shoots to grow into the tall, fern-like foliage that photosynthesizes and stores energy in the crown. If the plants show vigorous growth, a very light harvest of spears, lasting only about two weeks, may be taken in the second spring. A full, sustainable harvest, which typically lasts six to eight weeks, should only begin in the third spring after planting.