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Minter: Plant asparagus and see it grow for the next 15 years

If you really enjoy this unique vegetable, why not grow your own?
Asparagus 1

The following column was submitted to the Tri-City News from Brian Minter — master gardener, best-selling author, Order of Canada recipient and co-owner of Minter Country Garden Store.

Asparagus is one of our oldest perennial vegetables.

The generic word is derived from the Greek 'asparagos' meaning 'to tear,' which relates to the prickly nature of some stalks as they mature.

Asparagus, as one of today's highly prized gourmet vegetables, is relatively expensive for several reasons: it takes at least three years from seed until it comes into production; it requires considerable commercial growing area; and it has a limited production season.

If you really enjoy this unique vegetable, why not grow your own?

Asparagus is hardy from Zones 2 to 4, meaning it will tolerate temperatures as cold as -40°C.

To keep the cost down, commercial growers usually start asparagus from seed, but most home gardeners start it from two-year-old roots.

Once planted, asparagus roots are productive for at least 15 years.

'Mary Washington' has traditionally been the favourite variety, but newer, hybrid, all-male varieties, like 'Jersey Knight', produce larger crops of big, attractive green spears with purple bracts and tight purple tips.

‘Millennium’ is a newer variety from the University of Guelph and is one of the most productive yet. ‘Sweet Purple’ is a treat for connoisseurs because its purple spears have a 20 per cent higher sugar content and are usually eaten raw.

‘Rhapsody’ is a delicious white variety.

When it becomes established, the spears need to be covered with soil as they grow to keep them pure white, otherwise they will be green.

They truly are a gourmet treat and one with amazing flavour.

Due to the late winter this year, it will be about another two weeks before asparagus roots are available in garden stores. So, hang in there a little longer.

To grow asparagus, you need a really sunny location with well-drained, slightly alkaline soil.

It is very important to make certain the asparagus roots go straight down and because of this, the traditional method of planting involves trenches.

Furrows or trenches should be dug about 12 inches wide and 12 to 18 inches deep, depending upon the length of the roots.

Rows should be four feet apart.

The bottom of the trench should be filled with 2 to 3 inches of well-composted manures.

Mix the manure up well with the existing soil and then add a few inches of just soil on top. Create a mound of soil in the centre of the trench, leaving the crest about 3 to 4 inches below the level of the garden soil.

At this point, the asparagus roots can be planted. To speed up the rooting process, I always dip them in a mixture of warm water, root starter fertilizer and mud. This muddy concoction sticks to the roots and immediately begins to stimulate root development.

Lay the roots on top of the mound of soil in the trench, spreading the roots evenly on both sides of this small berm. Place the plants about 18 inches apart and backfill the trench, leaving the crowns or tips of the asparagus just barely covered with soil. Root growth will begin almost immediately.

Weeds can be a problem in new asparagus beds because well-established roots will intermingle with the asparagus roots. Keep your asparagus beds weed free by hand cultivation but remember to practice shallow cultivation for fear of injuring the asparagus roots.

During the summer, asparagus needs deep watering to keep the roots active and growing. Soaker hoses are the best means of watering these beds. During dry spells, water thoroughly at least once a week. As the asparagus plumes begin to develop, feed the plants with a high nitrogen fertilizer.

I prefer to use a slow-release food, like 14-14-14, for more long-lasting results. It is important to keep the tops growing to develop both food and strength in the roots.

If you are an organic buff, parsley planted with asparagus gives added vigour to both. Tomatoes planted near asparagus will keep away the asparagus beetle because of a substance in the tomato plant called solanine.

The second year after planting, you can begin harvesting a few spears for a period of four to six weeks.

When the spears are 6 to 8 inches high, cut them at a 45° angle about 1½ inches below the soil line, but be careful not to damage the crowns. At the start of the harvesting season, you will probably harvest every three days, but as the soil becomes warmer, a daily harvesting can take place.

If any spears get away on you, let them develop into foliage. Once the spears become very thin, it's a sign the roots are near exhaustion, and it is time to stop cutting.

Let the plumes grow all summer. In colder parts of British Columbia, leave them standing to trap snow for better winter protection. In the Lower Mainland, the plumes should be cut off in September and the roots covered with 4 inches of coarse manure.

It may seem like a fair amount of work the first year, but once established, with a little care, you will enjoy your own fresh asparagus for the next 15 years.