Growing asparagus is not a particularly quick or easy task. However, Asparagus is a perennial plant so once established, it can go on producing food for as much as 20 years, so it is worth considering if you have a larger plot of land where you can give it an area to grow without disturbing it too much.
Asparagus plants are quite fussy and particular about the conditions you grow them in. They need to be planted quite far apart (planted in rows between 12 to 18 inches apart) and they need to be planted from crowns in a very specific way.
A raised bed would provide the ideal growing conditions but bearing in mind that growing asparagus will require a fairly large amount of space, you will not get many plants in one. A 4ft x 4ft raised bed would only accommodate growing 6 asparagus plants, if planted using the row method, as the rows need to be spaced about 3 feet apart.
Alternatively you could use a ‘hole’ method where you did a hole for each individual plant with a small mound at the base of the hole – this will allow you to squeeze 8 plants into the same growing area if set in a staggered pattern.
It’s also important to keep your asparagus bed weed-free. The delicate roots of the asparagus eventually form a vast intertwined network throughout the growing bed, and You will not be able to remove weeds without disturbing or damaging them.
Use fresh, rich, well-drained soil containing well rotted manure and compost. This is your only opportunity to get the soil right as you will only be able to mulch afterwards. (lay nutrient ingredients on the top of the soil – not dig in) so it is worth spending some time and effort on getting it right.
Asparagus crowns are best purchased from a nursery. they come in the form of a bunch of stringy roots with one or two small shoots (see illustration).
Before starting, take your asparagus crowns, and place them in a bucket of water for a 20 mins or so.
Dig a trench (or hole) about 6 inches deep and about 14in wide.
At the base of the trench use the side of your spade or a trowel to crate a mound of soil about 4 inches tall.
Take your crowns and straddle the roota over the mound at the base of the trench or hole, spreading the roots around. The roots are delicate, so be careful not to snap them. Remember to plant them at least 12 inches apart – preferably 18.
Cover the roots with an inch or two of soil, just to hold the roots in place so that the shoots are just sticking out of the soil.
As the shoots grow, continue to add more soil, leaving them just proud of the soil each time, until the trench is eventually filled.
Water the newly planted crowns, and Keep the soil damp throughout the dry seasons.
Although the asparagus plant will produce small spears in the first year, it’s important not to pick them, but allow the plant to go on developing for two years before harvesting. Pruning the spears down to short stumps in the autumn of the second year should help the plants produce an abundant edible crop from year three onwards.
Once established, this is where growing asparagus comes into its own. Asparagus plants grow fast! During peak growing season, they can achieve as much as several inches of growth a day! So regular harvesting is important – several times a week would be good to aim for.
Wait for the spears to reach 4 to 5 inches in length before harvesting, then cut a few inches beneath the soil.
Only harvest up until about mid summer to give the plants time to recuperate and recover for the following years growth.
A typical plant will produce about 20 – 30 asparagus spears per year.