Gardening > Grow Your Own... Asparagus

Grow Your Own... Asparagus

Asparagus © Elena Elisseeva & Dreamstime
An asparagus bed can remain productive for up to twenty years so it represents a significant commitment in terms of time and space. A generous area of land is required which will not yield a crop for at least two years.

The type of soil needed isn't critical but it must be well-drained. Asparagus, however, will not do well in a very acid soil.

An asparagus bed needs a sheltered but sunny position, the soil must be well-prepared and every trace of perennial weed roots must be removed.

It is possible to grow asparagus from seed but this means that spears cannot be harvested until the third year. If one year crowns are purchased then cropping can begin in the second year. Sometimes two-to-three year crowns are available but they tend not to do very well.

If seeds are used they should be sown one inch deep in drills twelve inches apart in late March to the end of April. The seedlings can be thinned when they are about three inches tall. The following spring the strongest looking plants can be transplanted to the prepared asparagus bed.

Alternatively one year crowns can be purchased. These should be planted in trenches eight inches deep and twelve inches wide. Each trench should be three feet away from the next. Make a three inch ridge of soil at the bottom of each trench and then spread the crowns over the ridge about six inches apart. Cover the crowns with two inches of sifted soil. Gradually fill in the trench as the plants grow. Usually the trench will reach ground level by the autumn. Crowns can be planted from late March until the end of April but if the soil is cold and wet delay planting by a few weeks. To get as big a crop as possible it is a good idea to plant both early and later varieties.

The asparagus bed will need weeding carefully. Don't use a hoe, pull the weeds out by hand. Keep the bed watered in dry weather. The crowns will start to put up shoots soon after they are planted. These shoots must not be cut but allowed to grow fern-like plants. Remove any berries from the ferns and cut the ferns down in autumn when they have turned yellow, leaving one-to-two inch stumps above the ground. In the spring after planting (and every spring after) draw up a ridge of soil over each trench and apply a surface dressing of a suitable fertilizer.

There is some dispute as to whether a few spears can be cut during the year after planting between late April and early June. It is probably best to be cautious and take just one spear from each crown. In the second year after planting the crown asparagus can be cut every day between late April and early-to-mid-June. Cut before the spears get tall and stop cutting by mid-June. Any spears after mid-June must be allowed to grow into fern to ensure a good crop of spears during the next year.

Issues affecting your Asparagus crop:

Asparagus Beetle
These beetles are black with orange markings. The beetles and their grubs eat the stems and foliage. Use an organic spray at the first sign of infestation.

Slugs will spoil the crop.

Tender young shoots become black and have to be disposed of. Use fleece in frosty weather.

Violet Root Rot
The roots become covered in a purple-coloured mould. Leaves yellow and die. It is best to move the asparagus bed. Do not grow root crops there for three years.

Rusty coloured spots on the leaves in summer. Cut off affected parts and burn.

IF a sheltered spot is not chosen, wind can loosen the roots and rotting can occur. Provide some sort of wind break or support the stems in summer.

Thin Spears
Due to lack of feeding; over-cutting in the previous year; or cutting too soon after planting.

Year 1: Sow seeds March to April.
Year 2: Plant one year crowns either bought or grown from seed sown in year one March to April.
Year 3: Possibly cut a few spears April to June.
Year 4: Harvest all spears April to June.