Tips for growing asparagus

Asparagus beds take a few years to get established, but the actual work isn't that complicated or difficult.

General Info

Asparagus is a perennial vegetable. After it is established, it will return every year, and generally keep returning for 10 to 20 years.

If you plant asparagus from seed, you will need to transplant the resultant crowns (roots). You may transplant your crowns in either the spring or the fall, but regardless of when you choose, it is usually recommended not to harvest until the third year.

The best asparagus varieties for home growing are currently the "Jersey" hybrids: Jersey Giant, Jersey Knight, Jersey Prince, and Jersey King. Asparagus normally come as both male and female plants, but since these hybrids are all-male, they don't use energy producing seed and thus produce more harvestable spears. Plant about 5 to 15 crowns for each person (depending upon how much they like eating asparagus).

Growing Season

Asparagus are best planted in the spring after the soil has warmed up a bit. They mature in late spring, after which the plants will grow ferns, which will die due to frost.

Planting

From Seeds or Crowns?

If you plant from seeds, wait until the soil warms up a bit and there won't be any more frosts. After soaking the seeds in warm water overnight, plant them about half an inch deep and four inches apart. The seeds should germinate in about 3 to 4 weeks. They should grow into crowns in about a year, after which you can move them to their permanent homes.

If you plant from crowns (usually one year old roots), plant them as soon as the soil is workable. You can also plant crowns shortly before the soil freezes, in the late fall, for next year.

Preparing the Site

Asparagus likes plenty of sunshine, so be sure the site you pick has full sun for most, if not all, of the day.

For best results, asparagus should be planted in soil that is rich in organic nutrients and will drain well - it needs lots of moisture but shouldn't be drowned. Eventually the roots will go down quite a way (eight to ten feet) and get most of their moisture from there. If the area has a high water table, though, consider planting in a raised bed. The soil should be around pH 6 to 6.7 (slightly acidic).

Dig one or more one foot deep trenches, one foot wide, and as long as you can - if you can't make long trenches, dig several about four feet apart. Fill the bottom two-thirds of the trench(es) with a mound (low at the sides, high in the middle) containing a mixture of soil and compost and/or peat moss and/or well-rotted manure.

Place the crowns on top of the mound, buds facing up, with the roots extending down the sides toward the bottom of the trench. Place them about a twelve to fifteen inches apart - closer if you prefer thinner stalks; separated a bit more if you like thicker stalks.

Initially cover the crowns with about two inches of soil/fertilizer mixture and fill the sides of the trench so the bed is level. As the buds sprout, add more soil slowly over several days until the trench is full and level with the ground. Don't compact the soil or you may hamper plant growth.

Plant Maintenance

Using fertilizer

Your asparagus beds should be fertilized each spring just before the stalks begin to grow, and again just after you have finished harvesting them. Asparagus needs a lot of energy to grow and is a heavy feeder. 5-5-10 or 5-10-10 fertilizers are a good choice.



Weeding

Keep your asparagus beds well clear of weeds. If you plant both male and female plants, you will need to pull up all of the young plants that grow from the seeds produced by the female plants. Weeds and young plants will suck up the nutrients your asparagus plants need to produce good healthy spears.

Once the plants are up, cover the beds with a mulch of well-rotted hay or shredded leaves.

Watering

Asparagus should be watered heavily just after fertilizing, both before the growing-season and after the growing-season. Feel under the mulch every so often - if the soil is dry, it should be watered. Every two weeks will probably be enough, although if you have planted in sandy soil, you will probably need to water more frequently.

The asparagus plants will turn into ferns after the growing season. Do not, however, water the ferns after your first fern irrigation.

Dangers

Pests

Planting marigolds or tomatoes here and there in your asparagus beds can fight various types of Asparagus Beetles, as can ladybugs, their natural predator. Removing all of the mulch, etc., from the beds after the frost may stop beetles from wintering there. You may use a chemical pesticide if necessary - check with your local suppliers to get their recommendations.

Diseases

Diseases such as Fusarium and Asparagus Rust can be fought by ensuring you plant only disease-free seeds/crowns in disease-free soil, efficient weeding and, if necessary, chemicals such as zineb - again, check with your local suppliers to get their recommendations.

Harvesting

Don't harvest the first season after planting the crowns. Harvest only lightly, if at all, during the second season - only a few spears from each plant, and only for two to four weeks. Harvesting should be done based on spear height - not spear diameter.

How & what to cut

When the spears reach a length of six to eight inches or so, snap them off by hand close to the ground. Be careful not to injure any spears that haven't appeared. Stop harvesting when the new spears come in thinner.

Preparing for next year

The unharvested spears should be tended until they turn brown at the end of the season. Keep them standing up straight - you may need to tie them to stakes.

After the harvest, the plants will grow into ferns, which may grow six to seven feet tall. After they are killed by frost, you may leave them there to help insulate the plants from the cold. You should remove them in the spring.

The majority of the work involved in growing asparagus is concentrated in the first three years. After that, a bit of care and common sense will keep your beds producing for many years to come.

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