Before you rush out and buy asparagus plants you need to consider carefully where you plan to locate them. An asparagus patch can remain fruitful for 15 to 20 years and does not benefit from being lifted and shifted. They can be grown from seed however crowns are readily available in most garden centres and will give you a head start. The volume of plants required will depend upon a little on the variety you choose however 2 crowns per person should give a feast of asparagus in a good growing year.
When you are ready to plant the new crowns make sure you dig over the plot and remove any perennial weed roots. Dig in plenty of compost or manure. Give each crown plenty of space and plant approx 20cm below the soil surface. A new crop of plants should be left unpicked for the first 2 years in order for the plants to mature. Be patient and your plants will reward you with loads of tasty and tender shoots in year 3.
The shoots, which appear in late spring, will grow into ferns about 1 meter high and will need support as they grow taller to avoid root damage. These feathery ferns are an attractive addition to the garden through the summer but should not be cut for flower arrangements as they provide much needed nutrients to the plant for next years growth.
In early spring of each year treat the plants to a top dressing of compost, building the soil level up over the top of the plant stems. As the shoots appear and throughout the growing season keep the area weed free. In the autumn, when the ferns turn yellow, you should cut them back to 5cm above ground level. They make good compost so chop them up or throw them in whole and they will provide food for your garden next season.