Asparagus, packed with nutrients such as folate and vitamins A and C, can be eaten raw or cooked in a variety of ways. While asparagus requires some effort to grow, it's a hardy plant that does well in cool climates. With proper care, asparagus plants can produce for 15 to 20 years.
Salt has no discernible benefit as a fertilizer for asparagus. Salt contains sodium and chloride, neither of which are used by asparagus. It requires soils high in potassium and phosphorus. Salt should not be used as a fertilizer for asparagus, reports the Ohio State University Extension.
Years ago, gardeners used salt as a form of weed control for asparagus. Asparagus is more salt-tolerant than other plants because of its deep roots, so applying salt would kill many of the weeds without harming the asparagus. Given that weed control in established beds can be difficult because the spears break off easily, this seemed like a viable alternative. Salt should not be used for weed control in asparagus, though, as it will damage the soil.
Salt causes soil to form a crust, making it difficult for water to penetrate. Salt is also taken up by plants through their roots. While asparagus is fairly salt-tolerant, if you decide to grow other plants there, chances are they won’t grow well--if at all--in salted soil. Moisture can also move the salt to other areas of your lawn or garden, where it can harm desirable plants.
Given the harmful effects salt has on the soil, alternative are a better option. To fertilize asparagus, soil tests tell you exactly what you need. The Ohio State University Extension recommends 20 lbs. per 1,000 square feet of 10-10-10 fertilizer if you haven't done soil tests. Control weeds with mulch, hand-pulling and hoeing. You can also use a glyphosate herbicide for spot control as long as it doesn’t touch the plants, recommends the University of Minnesota Extension.