Planting & Seed Saving Notes

A Complete Guide to Growing Asparagus (from Crown and from Seed)

A Complete Guide to Growing Asparagus (from Crown and from Seed)

A Gourmet Harvest Worth Waiting For: Asparagus

Asparagus is a vegetable of the gods. At least I think it is! The delicate spears are a celebration of early spring. They taste of welcome fresh rain and greenness all around. Asparagus is a pleasure to grow and an event on the table either grilled, sauteed, served with lemon and butter or a rich hollandaise sauce. My mouth is watering, and it’s only February. The wait might kill me!

There is nothing like a fresh asparagus spear, broken off and munched right on the spot. It is so tender and juicy that you need to plant a generous amount for any to make it out of the garden and into the kitchen at all. The average yield for a 100′ row is 400 spears. It is rich in B vitamins, C, calcium, and iron – a perfect early spring nutrition booster.

The best time to plant asparagus is 3 years ago. But if you didn’t do it then, now is a good time too! Choose your location well because this perennial bed will last 20 years. The plant grows in full sun but will tolerate partial shade. It likes rich, well drained soil, the more compost the better.

Growing Asparagus Crowns

Generally people plant asparagus as year-old ‘crowns’ – a little like onion transplants. Asparagus is a perennial vegetable crop from the Lily family that can produce crops for 15 or more years.  Each crown can produce 1/2 pound of spears per year once fully established. Gauge your plantings accordingly! 

Because of the long production time, when choosing a bed be sure to consider a location where they can stay. Choose a sunny spot with well draining, loose soil. Heavy clay soils can be conditioned in advance with the addition of leaf mulch or straw and then finely tilled. Asparagus doesn’t like very acidic soil so it’s great to get a soil test if you’re not sure about your site! 

Asparagus crowns are usually planted twelve inches apart in rows spaced five feet apart. Dig a trench eight inches deep that is about four to six inches wide. Lay the crows in the trench with the roots fanned out and buds pointing up. Cover the crows with a few inches of soil. As the plants begin to grow and push through the soil, cover them with another inch or two. Continue covering the crows as they grow until the trench is filled. 

Weed the bed as needed. Fertilization will help these heavy feeders. Each year in early spring before growth and again after harvest, provide a balanced 5-5-5 or 10-10-10 fertilizer. 

Patience Is Key

The following spring do not harvest; your self-restraint will pay off in coming years! The next year harvest lightly, 2 to 3 weeks, each year adding a week or two to the harvest window, eventually harvesting for 8 weeks annually. Asparagus beds can be surface amended with well-aged compost and mulched annually to ensure healthy plants.

Leave the asparagus fronds as winter protection over the bed. Cut them back in early spring, around early April prior to the first emergent stalks. In the event of a spring freeze emergent stalks should be covered with newspaper, leaves or other mulch to protect them. Asparagus stalks can tolerate cool temperatures but freezing temperatures can ruin stalks.

What is the difference between growing from seed and from crowns?

It takes patience to start a bed from seed (an extra year), but it will save you money and often results in healthier, better producing plants. Start seedlings indoors in February or March. They like bottom heat and a soil temperature of 77 degrees F before sprouting, 60 to 70 degrees after sprouting. Plant them outside when all danger of frost is past. They will be about 12″ tall by then. Keep them well watered all season

Asparagus has male and female plants. The males are more productive because they don’t need to put energy into making seeds. You can tell them apart by looking at the flowers under a magnifying glass. Females have 3 lobed pistols, male blossoms are larger and longer. Some people weed out the females after harvest season and plant more the next year, endeavoring to have an all male bed.

Asparagus Pests

The two most common asparagus pests are Common Asparagus Beetle and 12-Spotted Asparagus Beetle.  Pick off any beetles you may find, pull off eggs and brush larvae to the ground where they will likely die before climbing back onto the plants.

Enjoy the challenge of asparagus. The few years of establishing these remarkable vegetables are nothing next to the 20 year gourmet garden you will have outside your door!


Article Written by: Angie Lavezzo

About the Author: Angie Lavezzo is the former general manager of Sow True Seed. Beyond her professional role at Sow True, Angie's passion for gardening extends into personal hands-on experience, fostering plants and reaping bountiful harvests.