Asparagus (Asparagus officinalis) is a perennial favorite in Nebraska gardens. Its green spears faithfully poking through the early spring soil are welcome signs to gardeners weary of winter. To maintain this rite of spring, proper approaches to weed control and fertilization are key cultural practices to be incorporated into the garden routine.
In an established asparagus bed, the gardener should be aware that just as much is happening beneath the soil as is happening above the soil. Therefore, manual weeding or frequent, shallow tillage with a hoe or other garden is recommended. The use of a rototiller significantly increases the chances of damaging emerging spears, the root system, or the crown from which the spears emerge. Straw mulch between the rows after tilling can help keep weed growth to a minimum.
Herbicide control of weeds in asparagus is possible, however, proper care and use is paramount. Contact herbicides, such as glyphosate-containing products, should only be used in early spring before the emergence of spears or after the final harvest and prior to extensive fern growth in the summer. Pre-emergent products, such as PreenTM, may be used, but also only before the spears emerge. Keep in mind that pre-emergent products will not be effective against weeds already growing. No matter what product is used, always follow label directions for application rates and personal protective equipment.
Contrary to popular belief, salt water, such as that from ice cream makers, should never be used to control weeds in asparagus. Salt degrades the pore structure of the soil, significantly reducing the ability of water to permeate.
In order to maintain strong production, asparagus requires regular fertilization. In late fall, the asparagus bed will benefit from the generous application of well-composted manure. A balanced, complete fertilizer, such as a 10-10-10, can also be applied in the late fall, or in the late spring immediately after harvest is complete.
- Frequent, manual weeding or light, shallow tillage with a garden hoe
- Use of a rototiller can damage shallow roots and emerging spears and is not recommended
- Application of mulch, such as straw, after weeding can help minimize weed germination and growth
- Contact herbicides (glyphosate-containing products) and pre-emergents should only be used when there is no above ground growth, e.g., early spring before spear emergence or immediately after the last spring harvest
- Salt should never be used for weed control because it destroys the pore structure of the soil and decreases water infiltration
- Always follow label directions for application rates and personal protective equipment
- Asparagus requires regular fertilization to maintain both quantity and quality production
- Composted manure can be applied in the fall
- A balanced, complete fertilizer, such as a 10-10-10 product, can be applied in late fall, early spring before spear emergence, or in the late spring immediately following the last harvest