Guide to Growing Asparagus
These succulent spears appear only briefly in the late spring, but once established, they crop for many years with very little maintenance. Tender spears appear in the late spring and can be harvested for several weeks.
How to Grow
This perennial plant grows in the same spot for up to 20 years, so choose the site carefully. It prefers a sunny, sheltered location with well-drained soil, improved before planting with plenty of well-rotted organic matter. It is usually grown from young bare root crowns, planted in the spring or can be planted as container-grown specimens at any time of year if well watered. For the most productive plants, choose all-male varieties.If you want a lot of plants and are willing to wait for them to grow, asparagus can also be grown from seed. Sow the seed under cover in late winter into modules, then plant out the seedlings in the spring once they have been hardened off.
New crowns should be allowed to establish themselves for at least two years before harvesting. Keep the plants well watered all summer, mulch with well-rotted organic matter in the fall, and apply a balanced granular fertilizer in the spring, before and after harvesting. During summer, support the tall ferny growth with canes, and keep plants well-weeded. At the end of summer, cut down the yellowing growth to 1 inch above the soil, and clear away all plant debris.
Varieties of Asparagus to Try
All-male asparagus hybrids (M) are the best choice because they don’t waste energy producing seed, giving stronger crops. Most named varieties are sold as plants or as bare root crowns, including: ‘Ariane’, ‘Backlim’ F1 (M), ‘Connover’s Colossal’, ‘Gijnlim’ (M), ‘Jersey Giant’, ‘Pacific Purple’ and ‘Theilim’ F1 (M).
Planting and Harvesting
Follow these two simple steps to successfully grow and harvest asparagus spears:
- Dig a trench, 8 inches deep, add rich organic matter, and mound up the base. Position the bare root crowns, spacing them 12 inches apart, and spread out the roots. Cover them with soil, and water well.
- Mature plants, planted at least two years earlier, should be picked as the new shoots appear in spring. Cut off the spears 1 inch below soil level when they are about 8 inches tall. Remove every spear to encourage more to grow.
Watch Out for These Pests
Slugs and snails eat the emerging spears in the spring and can be particularly damaging. Apply slug pellets, use beer traps, or lay gritty barriers around plants. Asparagus beetle larvae and adults might also feed on the spears and foliage, weakening the plants. Destroy them on sight. Spray badly affected plants with a suitable insecticide.