Growing Asparagus in the Vegetable Garden
Growing asparagus calls for a good deal of patience; but it is an expensive delicacy to buy, and its decorative foliage adds charm to an herbaceous border. Many gardeners, however, set aside a small bed exclusively for asparagus because, once established, the plants will crop for many years.
You can raise asparagus from crowns or from seed, the former being the easier method. Either 1-year-old or 2-year-old crowns may be used: the 1-year-olds tend to establish themselves more readily, but they are not always easily available. The crowns should be planted as soon as possible after purchase in March to April: they may suffer irreparable damage if they begin to dry out.
If you are growing asparagus from seed it should be sown in a specially prepared seed bed in April. The seeds should be sown at a depth of 50 mm (2 in) in rows that are 300 mm (12 in) apart. In the summer thin out the plants so that they are about 150 mm (6 in) apart; keep them well watered in dry weather and weed-free.
Asparagus plants are either male or female, and healthy seedlings will flower in their first year. Male plants produce more shoots, so it is sensible to discard the females (you can tell the latter from their or, later, their berries). Select the crowns from the remaining plants, and plant them out in March to April.
In a small garden three beds, either separate or as a part of a border approximately 1 m (3-1/2 ft) square, each containing 5 plants, should provide a good supply for two people; alternatively, the plants may be grown in rows 300 mm (12 in) apart with 300 mm between each plant.
Successfully growing asparagus depends greatly on careful preparation and cultivation of the bed. Double digging is strongly recommended because the plants develop deep roots; they also spread extensively, so theshould be thoroughly cultivated to a distance of about 600 mm (24 in) around the bed. Dig the bed in the autumn. Add plenty of compost and other organic material such as leaf mould or, if possible, farmyard manure (if you live near the sea, well-rotted seaweed is even better).
Leave the bed in a rough condition over the winter, then rake it level and clear debris and stones before spring planting. If you are using 1 m (3 ft) square beds, put one plant in the centre and the other four at each corner. Each hole should be 125-150 mm (5-6 in) deep, and wide enough to spread out the radiating roots. Then raise the centre of the hole so that the crown rests on a mound about 75-100 mm (3-4 in) below the surface of the bed. Fill in the soil, firming it gently. If you are planting in rows, take out a trench about 125 —150 mm (5-6 in) deep and wide, mound the centre to a depth of 75 —100 mm (3-4 in), and plant the crowns about 300 mm (12 in) apart along the ridge; fill in. Water the bed thoroughly after planting. Keep the beds where you are growing asparagus weed-free, and apply a general fertiliser annually from the second year after planting.
When you are growing asparagus, ideally you should wait until three years after planting before harvesting your first crop. However, the less-patient grower can take a few shoots, in May, two years after planting 1-year crowns, or only year after planting 2-year crowns. In subsequent years the weight of cropping may be increased. The shoots can be harvested when they show about 100 mm (4 in) above the ground; they should be cut with a sharp knife 75-100 mm (3-4 in) below the surface of the soil.
After harvesting, the plants are allowed to grow on. In the autumn the foliage turns yellow and should be cut down and burnt before any berries have time to fall and give rise to unwanted seedlings. This is also the time to apply a mulch.
ASPARAGUS BEETLE AND OTHER PESTS
When growing asparagus plants, be aware that they will suffer from various pests.
The black-and-yellow asparagus beetle and its grey grub are often seen on the foliage and stems and can be dealt with by applying derris or malathion. Where the red and black asparagus beetle has attacked the foliage, leave about three stems of fern at the end of each row. The beetles that fell to the ground when the rest of the fern was cut will climb up the remaining stems where they may be killed with D.D.T. powder.
Slugs may be killed with Draza pellets.
CROWNS: ‘Regal Pedigree’
SEED: ‘Martha Washington’; ‘Connovers Colossal’; ‘Limburgia F1’.
Argenteuil Early, delicate flavour and fine texture; not a very heavy cropper.
Connover’s Colossal, good thick-stalked variety with slender, pointed buds.
K.B.F., the best heavy-cropping strain; sticks are large and delicious.
Site: Preferably sunny, fairly open but protected from wind
Soil: Well-drained, with ample compost and other organic matter
Harvest: April—May in first season; thereafter, April—June