With proper management, asparagus will stay productive for at least ten years, or maybe much longer depending on the satisfaction level of the plants. When you invest time and space in garden asparagus, the returns keep coming for a long, long time.
Seedlings purchased from a nursery grower can sometimes be crowded, three to each small container, so dividing them can be tedious because the seedlings can become knotted with one another. Buying crowns is better to enable planting at a proper spacing.
Asparagus planting tradition calls for setting plants in a trench that is gradually filled with soil, a nice but not necessary operation. As long as asparagus is planted 4 inches (10 cm) deep in rich, fertile well drained soil that is free of weeds, in a climate cold enough to keep the plants dormant for at least two months, the plants will move themselves up or down in the soil to find their most comfortable depth.
New asparagus plantings need two years to fill out, during which time they require periodic weeding and mulching. In the third year, plants produce enough spears for picking, though it’s still important to leave behind enough fronds so that the plants become dense with foliage by midsummer.
Since the edible parts are the newly emerged stems, or unopened fronds, there are two ways to do this. Most gardeners harvest all spears for six weeks in late spring, and then let the plants grow freely for the rest of the summer. However, you also can allow one or two of the early fronds to grow, which may help energise the plants to produce thick spears for a longer time.
The asparagus patch turns into a ferny hedge in summer, which gradually yellows and dies when winter returns. Asparagus beetles can hide in the withering fronds, so they should be clipped off and composted before the bed is tucked in with a winter mulch of chopped leaves or wood shavings.
The growth cycle begins again in late winter, when the bed gets treated to a nourishing blanket of rich compost and straw clipped from winter-weary ornamental grasses.
The beauty of pristine asparagus spears is matched by their impressive nutritional profile. In addition to vitamin C, asparagus provides three unusual nutrients - folacin (good for the liver), rutin (good for the blood) and glutathione, one of the most potent of all plant-based anti-carcinogens.
In combination, these and other nutrients in asparagus may help prevent hypertension when eaten regularly. In terms of cooking methods, steaming asparagus preserves more nutrients than grilling, baking or pan-frying.