How to grow asparagus in your garden To plant, dig out a shallow trench 30cm wide and 20cm deep. Incorporate well-rotted manure to the base of the trench and cover the base with a 5cm layer of excavated soil. Be sure to buy fresh crowns, as they often dry out while on display. Hoe a 10cm-high ridge of soil along the centre of the trench. Place the crowns on top of this ridge. Allow 30-45cm between each. Spread roots evenly over the sides of the ridge, and then cover with excavated soil so that only the tip of the crown shows. Space rows no closer than 45cm and stagger the plants in adjacent rows. If the soil is dry, water in and mulch. How to grow Annual weeds are best winkled out by hand, but can be partially prevented by covering the beds with black plastic in winter. In late winter, mulch with weed-free compost to discourage weeds and feed the plants. Every spring, apply 100g per sq m of general fertiliser such as Growmore or fish, blood and bone, and again after harvest if growth is weak. The foliage is essential to build up reserves for future crops. Keep it upright with stakes and string, and free of asparagus beetle. If you allow the foliage to yellow in autumn before cutting it down to soil level, resources will be transferred to the roots to boost spring cropping. Modern cultivars are all male, as male plants produce more and better spears. Female plants, which have berries, do arise in so-called all-male cultivars, and account for about half the plants in non all-male cultivars. Female plants and seedlings should be removed. How to harvest Don't cut any spears for the first two years after planting. In the third year, gather spears from mid-April for six weeks, but in following years, if the plants are strong, cut for eight weeks. Slice off spears with a sharp knife just below the soil before they exceed 18cm tall. In warm weather, this may mean cutting every few days. Watch out for... Slugs and snails These browse growing tips, spoiling young spears. They are especially active at night and after rain. Use slug control. Asparagus beetle Adult beetles and their larvae strip the bark and foliage. If picking off does not resolve the problem, try a spray of natural pyrethroid insecticide. Frost damage Frosts cause distorted or dead spears, often some time afterwards if the tips are just below soil level. Cloches or fleece can hold off light frosts. Recommended 'Connover's Colossal" (AGM) Not all-male, but seed is cheaper. Gijnlim" F1 AGM All-male plant, popular and reliable. Guelph Millennium" F1 (AGM) All-male, matures later, useful in frosty gardens.