Asparagus is a perennial crop that is very well suited to the home garden. This is good, since the cost of certified organic asparagus can be quite high in stores, even at the height of the fresh asparagus season. As the price of fuel continues to increase, so does the cost of most foodstuffs – especially highly perishable crops such as asparagus.
It was once believed by the ancient Greeks that asparagus had magical properties, since it was capable of restoring people to health after long winters. It certainly is among the very first crops to come up in the spring, even in a garden planted with winter crops the previous autumn. Moreover, they are packed with vitamins A and C, as well as plenty of minerals. Even pickled asparagus, a favorite among many enthusiasts, retains a significant amount of dietary nutrition.
While heirloom varieties of this dioecious crop naturally have an even number of male and female crowns, there are several male-only hybrid varieties that can increase yields by as much as three times. Female crowns that produce a proliferation of berries on the “ferns” each year can quickly become a pest problem and must be managed carefully.
With few exceptions, experts agree that asparagus is a heavy feeding crop that is especially hungry for nitrogen. Generous applications of compost or well-rotted manure are made yearly, with additional side-dressings of blood or feather meal made twice during the growing season.
Since they are such an early crop, leaving plenty of open space that attracts weeds each year, many choose to plant between asparagus furrows with legumes. If tilled back in as a green manure crop, these can provide plenty of slow release nitrogen that will be available in the early spring when the pants need it the most.
Most home gardeners start with asparagus “crowns” rather than trying to start directly from seed. If starting from seed, there won’t be a crop until the following year because the seedlings will need to be transplanted in the autumn to their permanent location. When begun from crowns, fresh asparagus can come up as early as the next spring, though yields are best from plants that are at least three years old.
Mature asparagus crowns are unusual in that they’ll tolerate a rather wide range of soil pH conditions, ranging from slightly acidic to slightly basic. They are also able to tolerate applications of rather strong fertilizers directly on their roots without suffering fertilizer “burn.” It is, in fact, very common to plant crowns in trenches already lined with fertilizer.
Crowns are planted relatively deep – it’s not uncommon to see them set in as many as 8-10 inches (20-25cm), since asparagus is known for pulling itself out of the ground unless constantly mulched over. It is a good idea to plan on planting about 10 crowns per person in your household to keep everyone in plenty of fresh asparagus throughout the growing season, with about half that required from all-male cultivars. Like most certified organic asparagus growers, you can expect about ½ pound of spears from each plant over a 4-8 week harvest period, depending upon how old the crowns are.
After planting, it’s best to not harvest spears in the first year of production, allowing the new plants to establish themselves further in the subsequent season. Keeping weed pressures down is especially important if starting asparagus from seed, but this is also true of any new planting. Keeping weeds down will reduce competition as well as some pest problems in this generally trouble-free crop.
In subsequent years, fresh asparagus spears should be harvested as soon a they’re as wide as a pencil. While you may let them get larger, the stalks can become woody. Blanched asparagus seen in stores is produced by covering the emergent spears with a cardboard box or another covering to allow the to come up in total darkness and is popular with home-pickled asparagus, though it reduces the vitamin content of the resultant asparagus by quite a bit.
Asparagus are generally trouble-free plants, related to the lily. However, there are a few specific problems such as the asparagus beetle and asparagus rust. These can be kept under control with choosing resistant varieties, avoiding planting them near onions and keeping he weed population down.