How to Grow and Care for Asparagus

How to Grow and Care for Asparagus

Last Updated on December 9, 2018 by Kimberly Crawford

A welcome delicacy from the spring garden, hardy perennial asparagus grows easily from seed.

How To Grow Asparagus

Native to the Mediterranean and eaten by the ancient Egyptians and Greeks, succulent asparagus spears are ready for harvest when most other plants in the vegetable garden are just getting started.

Saving Seeds From Your Own Plants

asparagus plant care

You may expand your asparagus bed by saving seeds from the female plant. Simply cut the ferny plant top in late fall when the berries are red.

Hang the fern to dry then soak the dried berries in water to soften the skins. Squeeze out the seeds and rinse off the pulp.

Dry seeds between paper towels for a day or two then store them in a sealed plastic baggie and refrigerate until ready to sow. To make sure they remain dry, slip in another small piece of paper towel with the stored seeds.

Growing Indoors

To gain an extra year of growth – and who doesn’t want to eat these tasty vegetables as soon as possible – start your seeds indoors in February. When using purchased seeds or your own saved seeds, presprouting will ensure greater success.

Spread seeds between folds of lightly dampened paper towel, slip into a plastic baggie and seal. Lay the baggie on top of your refrigerator where it’s warm. Expect germination within 10 to 14 days.

Sow your presprouted seeds in 3 1/2 to 4 inch pots and place on a sunny windowsill. Water as needed and fertilize only once, if at all, with a diluted liquid organic fertilizer.

Planting Young Asparagus

asparagus hero

Prepare your asparagus bed with deep fertile sandy loam soil. Low fertility can cause fibrous spears. Attention to plant spacing and soil pH will reward you with many years of this delicious treat.

After the last spring frost, dig holes 8 inches deep then carefully remove your new asparagus plants from their pots and settle them in the bottom of the holes.

Fill each hole with soil about half way, making sure the greens are still above the soil. Space the plants 12 inches apart. Over the summer, gradually fill in the planting holes to the surface as greens grow above ground level. Deep planting will encourage a strong root system and protect the slender shoots of young plants from heavy winds.

Asparagus has plenty going for it. The first vegetable in the spring garden after a long winter, this hardy perennial can last for 20 or 30 years in well planned asparagus beds. A highly nutritious vegetable, asparagus deserves a place in every garden.

How to Care for Asparagus

Although asparagus requires minimal care, attention to asparagus beds will keep this perennial productive for many years.

Pushing up through cool spring soils, asparagus spears signal the start of the growing year. While much care is given to asparagus during the picking and eating season, it is all too easy to neglect them once asparagus harvest is over and annuals compete for the gardener’s attention. Vigilance throughout the growing season will reward the gardener with healthy crops year after year.

Asparagus Beetles

orange beetle

The main villain in asparagus beds is the asparagus beetle. In winter, both common and spotted asparagus beetles live in old fronds, stalks and garden trash remaining in the asparagus bed as well as any hollow stems protruding above the soil.

Common asparagus beetles emerge just in time to share the first asparagus harvest with the gardener. About 1/4 inches long, they range in color from metallic blue to black.

Their wing covers are decorated with three creamy yellow rectangles or spots with reddish margins. Beetles lay their eggs on the edge of asparagus fronds and on the tips of the spears.

Eggs hatch after about a week into light gray or green larvae with black heads and move to the ferns to feed. After two weeks the larvae fall to the ground and pupate in the soil, emerging as adults about a week later to start the cycle all over again.

The spotted asparagus beetle appears a bit later than the common beetle. It is reddish orange with six black spots on its wings. Spotted asparagus beetle larvae prefer the berries growing on the ferns.

Adults of both species feed on the spears, causing browning and scarring. Larvae and adult beetles also eat the ferns.

Foil Asparagus Beetles Organically

organic remedies for orange bugs

Harvest spears as soon as possible as beetles are attracted to plants with abundant foliage. Leave a small part of the crop unharvested to draw asparagus beetles away from the main crop.

Asparagus beetles avoid tomatoes. Plant a few tomatoes around asparagus beds. Choose a short determinate variety so as not to shade the asparagus fern later in the season.

French marigolds deter asparagus beetles with the added benefit of also repelling the tomato worm. Plant a few marigolds with both asparagus and tomatoes for double protection.

Make an insect spray from diluted liquid garlic concentrate. It acts as a natural defense against asparagus beetles and will not harm the plants or alter their smell or flavor.

Attract beneficial insects such as ladybugs and lacewings who love to eat the eggs and small larvae of asparagus beetles. Lure them to the garden with some of their favorites – alyssum, geraniums, lilies, cosmos, parsley and cilantro.

Pick off adult beetles, eggs and larvae and drop them into a pail of soapy water.

After the first fall frost, pick up garden debris and turn soil over around plants to disturb overwintering beetles.

Harvesting and Caring for Asparagus Beds

Harvesting and Caring for Asparagus Beds

Harvest asparagus when the spears are 4″ to 10″ long. Harvest every other day to prevent spears from becoming fibrous. Spears should have tight heads. Any loosely formed heads are over mature.

Cut the spears 1″ to 2″ below soil level with a good fish-tail shaped asparagus knife, strong enough to push into the soil and sharp enough to make a clean cut.

First year asparagus grown from seed or first year crowns, should not be harvested. Leave them to grow ferny tops to manufacture and store a good energy supply for the following year. The plant is weakened if it must continually send up more spears to collect food for a healthy root system.

In the second year, harvest spears for about 6 weeks. In third and successive years the spears may be harvested for 8 weeks. Do not be tempted to harvest longer. When the spears begin to thin to less than 3/8 of an inch it is an indication that the plants are low on nutrients and vigorous growth has stopped.

After harvest, keep asparagus beds free of weeds and continue to monitor for pests. Water asparagus when you water the rest of the garden. After the first hard fall frost, cut off the fern tops at ground level, clear away all debris and apply a mulch of clean straw, compost or manure.

With a little care the asparagus garden will continue to provide a fresh supply of succulent, nutritious spears every spring for a very long time.

How to Grow and Care for Asparagus