Asparagus Harvesting – How And When To Pick Asparagus

By: Becca Badgett, Co-author of How to Grow an EMERGENCY Garden

Harvesting asparagus is worth the wait, and wait you must if you have started a new asparagus bed from seed or crowns. The delectable spears are not of edible quality until the fourth year after planting seeds. Asparagus harvesting then becomes more worthwhile each year.

Planting asparagus from seed allows one to grow any variety of the vegetable, but growing from one year old crowns allows for harvesting asparagus more quickly– three years after planting crowns. Learning how to pick asparagus ensures the lifespan of your asparagus bed.

Male or Female Asparagus

Asparagus plants are either males or female. The female plant will develop many spears, but when harvesting asparagus one will have the most productive harvest from male plants.

Learning how to harvest asparagus includes knowing the difference between the male and female plants, which is easily discovered once the delicious vegetable appears and grows. Female plants devote much of their energy to seed production and can be identified when red, berry-like seeds appear later in the season.

Male plants, who devote no energy to seed production, offer thicker and longer spears which are what one desires when harvesting asparagus. Newer varieties of asparagus are available that offer only male plants not needing pollination.

How to Harvest Asparagus

Asparagus is one of the earliest vegetables from the garden in spring. Knowing when to pick asparagus will result in the most flavorful experience from your crop.

In the third year of growth, after planting one year old crowns, spears of plants will be ready for asparagus harvesting. During this initial harvest year (year three), plants should only be harvested the first month of optimum production. Removing the spears for more than a month during this important year of growth will weaken and possibly kill the plant.

Asparagus harvesting should begin when the stems are 5 to 8 inches (13-20 cm.) long and as big around as your finger. Of course, the width will vary from male to female plants. Length may dictate when to pick asparagus, but you will want to get it early enough in the season that it is tender.

Cut or break the spears from the point closest to their attachment to the fibrous roots. Excessive disturbance of the area can result in damage to spears which have not yet broken ground.

Once you know how to pick asparagus, you will delight in spring asparagus harvesting in future years. The properly prepared and harvested asparagus bed will increase in yearly production for many years, generally for as long as 15 years and possibly up to 30 years, with the vegetable becoming more abundant.

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Picking asparagus is usually done during the second or third year after planting, since asparagus can take up to three years to produce an optimal harvest. If you harvest asparagus during the first year, pick only a few spears to allow the remaining spears to grow ferns and provide the plants with adequate energy.

For subsequent years, harvest spears that are about the size of your small finger or larger. You can pick asparagus for one to two months, stopping once spear growth begins to slow. Use your fingers or a sharp knife to cut the spears at ground level.

How to Extend the Asparagus Harvest

There are some proven ways to increase and extend the asparagus harvest:

  1. Plant crowns at different depths, for example, 4 to 6 inches (10-15 cm), 6 to 8 inches and 8 to 10 inches. Spears from crowns planted a differing depths will emerge at different times the shallow plantings will emerge first. This method will result in a longer harvest, but deeper set plants may be less productive than shallow set plants—shallow set plants will have a smaller spear diameter and deeper set plants will have a larger diameter.
  2. A second way to extend the harvest for a few weeks is to remove mulch from half of the asparagus bed early in the season allowing the exposed soil to warm more quickly. This will cause sprouts to emerge earlier. When spears begin to emerge, remove mulch from the second half of the bed to allow the rest of the spears to emerge a few weeks later. Don’t pull back the mulch too early as frost can make spears inedible.
  3. Similar to the second method is a third: When the harvest season is about half complete, mound up 5 to 6 inches (5-8 cm) of soil over unharvested rows of spears. The mounded soil will lower the temperature around the crowns and increase the size of spears still in the ground (the soil will also blanch or whiten the lower portion of the spears).
  4. A fourth method to extend the harvest is to cut only half of the spears that emerge in the spring. Let the other half grow on to become ferny bushes, then in midsummer cut the bushy foliage down to soil level forcing the production of new spears. If you cut down a few bushes at a time there will be an extended, successive growth of new spears. Commonly, summer-forced plants produce one large flush of spears and then decline. Do not force spring-harvested plants in midsummer (for a second harvest in one year), you will weaken the crowns.

After ferns turn brown and die in the fall, mow them down in preparation for the next growing season. Avoid tilling asparagus beds since tilling will damage crowns.

A mature asparagus plant can produce ½ to ¾ pound of spears each season. Plant approximately 20 plants per household member.

How to Harvest Asparagus

If you are growing asparagus for the first time, then you probably have some questions about when to start harvesting and how to go about it. If you’ve forgotten everything your grandma taught you, or you were just too young to remember anything past that wonderful taste, we hope this will help.

The very first rule is patience! An asparagus bed, if established and maintained properly, can produce asparagus spears in excess of 15 years. In fact, some asparagus beds have been producing for 30 years! So, the first year you want to avoid harvesting, except maybe to get a very tiny taste of what’s to come, and concentrate on growing the healthiest and strongest root system possible.

The First Year

We recommend babying your asparagus through the first year. Invading perennial grasses are young asparagus’ worst enemy, so keep them under control as your young plants are becoming established. Depending upon where you are planting, you may want to install a barrier, keeping it in place through the first year, to be removed at a later time if you choose.or not. The root system of asparagus goes deep and becomes quite extensive, but the plants need that first full year to really take hold and to survive the winter, especially in the coldest regions. You should provide 1 to 2-inches of water per week during the first two years and feed well. After the second year, you can water more infrequently. You might want to use a soaker or drip hose through your asparagus bed, rather than watering from the top as this will allow the water to soak deeper, instead of settling on the tops of the plants there will also be less evaporation, resulting in less water use. Applying mulch around your plants will also conserve water, as well as inhibiting weed and grass growth.

As the spears are left to grow past the point of harvesting, the tops will open up and become fern-like. They are actually quite pretty, but also a very important aspect to the continuing good health of your asparagus bed. Using photosynthesis, these ferny tops will send food throughout the spears and into the crowns below the surface, ensuring the perpetual harvest that this perennial vegetable provides.

When it comes to cutting back your asparagus plants , there are basically two schools of thought. Some gardeners cut them back to the ground once they turn brown, going dormant, usually after the first heavy frost. In fact, some people just mow them down as close to the soil as possible, either adding the foliage to their compost bin or discarding it. The other half of asparagus growers will leave the ferny tops to catch the snow and to protect and insulate the plants, while providing necessary moisture throughout the winter and into early spring. Cut them back in March or early to mid-April, depending upon your climatic zone. Besides helping your plants to survive the winter, the brown, feathery ferns will add a bit of winter-time interest to your stark garden landscape, especially when coated in layers of sparkling hoar frost.

The Second Year

Finally, your patience has paid off! The spears are growing and you can start harvesting, but only for a little bit and only a little at a time. At no time should you harvest spears that are not at least as big around as your little finger. For this second harvest year, we suggest that you only harvest for the first 2 to 3 weeks. Heavy and continual harvesting past this point may weaken the plants, meaning that your asparagus bed will not continue to develop well for subsequent years. Just a little more patience is required. Time flies and a little patience now will reap huge rewards in three, four, five..fifteen or twenty years!

In most areas of the country, you will be able to start harvesting in May and continue into June. Asparagus is considered a cool weather crop and will be one of the first vegetables ready for harvest, even before your lettuce, broccoli and cauliflower. However, in more temperate climates, like that of southern California, you may have to treat your asparagus a bit differently, keeping track of the normal growing cycle for this perennial and allowing the ferny tops to grow and develop, rather than harvesting for an extended period just because you can. And then cut the plants back in late fall or early winter to encourage dormancy that occurs naturally in other climates.

As in all things gardening, gardeners have different ideas on what is the best way to harvest. Some prefer to use their thumb and forefinger to snap the spear at ground level, while others will use a sharp knife or asparagus harvesting tool to cut the spear one or two inches below the soil. It is our belief that use an asparagus knife to cut below the soil allows the plant and crown to be protected by that layer of soil, from both the hotter summer temperatures and marauding pests. A clean, sharp tool will also ensure that the plants are not stressed from the cutting. Pulling and tugging while snapping the spear can result in damage to the crown below the spear, which is already developing new buds for next year’s harvest.

Don’t forget! Only harvest this second year for 2 to 3 weeks! Your patience will be well-rewarded.

The Third Year and Into the Future

Now that your asparagus bed is well-established, you can harvest spears that are emerging which are 3/8 or larger (about the size of one’s little finger). Also, don’t submit to the myth that the larger the diameter of the spear, the less tender they are. That is just not the case at all. What IS true, is that as the season progresses, the part of the spear below the ground and possibly 1 or 2-inches up, may become somewhat tougher. This is just a fact of life when it comes to asparagus and one easily remedied by just cutting off the tougher part. You will still have plenty of tender asparagus spear above this point. If you’ve missed harvesting some spears and the tips are no longer tight and closed, you will be a little disappointed in the quality, so allow those spears to open and become ferny. You won’t be wasting them, just allowing them to become next year’s harvest.
As a rule, you will harvest every other day when the spears are between 4 and 8-inches tall and usually for a period between 6 and 8 weeks, depending upon your geographical location, and also depending upon the weather for that particular year. Hotter weather will shorten your harvesting season, while cooler weather will extend it.

Again, once you notice that the emerging spears are smaller than your little finger, quit harvesting and allow the ferny tops to develop, effectively perpetuating the cycle that will have your grandchildren and great-grandchildren harvesting the asparagus bed you plant today. Early summer mornings, working by grandma’s or grandpa’s side, will be a perennial memory!

Summer Asparagus Garden

After harvest, let the plant’s fernlike foliage grow tall. Summer growth allows asparagus roots to grow large and store energy for the following year’s spears. Stakes and string will keep plants upright. In breezy areas, plant rows parallel to the prevailing wind so that plants can support each other. Crowns grow upwards about 1 inch each year, so spreading compost across the planting bed or along rows in summer will both feed plants and raise the soil surface.

To get a second or more harvests each year, plant twice the number of plants or more needed for each person (40 rather than 20) then harvest only half of the bed in spring and let the other half grow on. In early summer, cut down the top growth in the half of the bed that was not harvested. This section will send up new spears in a few weeks that can be cut in late summer or early fall for a second harvest. If the growing bed is large enough, you can divide the bed into sections and use this method for a new 2-month harvest every 8 weeks, multiple asparagus harvests each year.

Asparagus plants after autumn with hoar frost

When and How to Plant Asparagus - Trenching

Asparagus planting can begin as soon as the ground can be worked, which usually means that the soil temperature should be around 5°C or 40°F. Asparagus planting can be started any time in between the last frosts of early spring.

Here are the guidelines for how to plant asparagus:

    Dig a trench 18" wide and 10" deep for growing asparagus

Mix a liberal amount of compost or fertilizer that is high in nitrogen, potassium and phosphorous, into the soil removed from the trench. We suggest asking local gardeners for their recommendations regarding the quantity of fertilizer/compost to use for your soil.

Fill the trench back in with the mixture of compost and soil until the trench is now only 6 inches deep.

Tamp it down, and place the roots in the soil, crown side up,

2 feet apart from each other.

Cover with 2-3 inches of the remaining dugout soil/compost mixture. This covering will protect the roots from subsequent frosts.

  • As the plants sprout, continue to fill in the trench until it is full. It should take most of the first growing season to fill the trench. Filling gradually aids in keeping down weeds(because the soil is continually disturbed).
  • The First Two Years

    When considering how to grow asparagus from root, it is important to know that asparagus will only fully produce in the third year. You can harvest shoots in the second growing season that are at least 7 inches high. You should not pick beyond one month, however, but wait for the fuller harvest in the third year. It is important to let the majority of the spears grow, and allow the plant to fern(grow feathery tops).

    The ferns aid in photosynthesis and will strengthen the entire plant by transferring carbohydrates and energy to the roots. You should also continue to fertilize once in the Spring and Fall.
    Each Fall, when the leaves have been killed off by frost, the stalks should be cut down to ground level.

    Watering Asapargus

    A general guideline is to water your asparagus once a week. Asparagus does not need a lot of water. If you experience rain at all during the week, you do not need to water.

    Weeding Asparagus

    Weed around the plants, but be careful to avoid damaging the roots. Hoe the weeds out with shallow strokes. You should be careful not to till deeper than 3 inches. Many people also cover the ground with a heavy layer of mulch, or hay, to keep the weeds at bay. This layer of mulch will also keep moisture in the ground for the benefit of the asparagus plants, and will give you the best chance of growing asaragus successfully.

    Watch the video: How to harvest asparagus

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