Growing asparagus is a long-term investment that can provide bountiful harvests for up to 20 years. Asparagus can be developed from crowns or seeds and requires a protected site with free-draining soil. In this care guide, we will cover the different aspects of growing asparagus, from choosing the right cultivar to soil preparation, sowing, and harvesting. Asparagus spears are a delicacy and can be quite expensive, making it a valuable addition to any garden. With some initial patience and care, growing your own asparagus can provide you with a sustainable and delicious crop for years to come.
Asparagus plants can live for up to 20 years, making it a long-term crop. They can be grown from seeds or crowns, which are plants that have been dormant for one year. They require a protected location with soil that drains freely, ideal in an asparagus-only bed. Except for weeding, mulching, and cutting back in autumn, there isn’t much maintenance required if your asparagus bed is already established.
Planting a new bed of asparagus takes some patience at first, but the investment will pay off in delicious harvests for years to come. Before cutting your first spears, it is best to give new plants time to spread out for a few years.
Asparagus is collected for around two months in spring and late-spring, when little else is cropping, making it even more exceptional. Asparagus lances are likewise very costly to purchase, so are certainly worth growing in the event that you have the space. Ten spears should be produced each season by an established plant.
Shoots should be allowed to develop into tall ferny plants throughout the remainder of the summer after the harvesting period. Then just chopped to ground level in pre-winter, and they will re-sprout in spring, prepared for harvesting once more.
When it comes to choosing asparagus plants for your garden, it’s important to consider the difference between male and female cultivars. Male plants generally produce more and better spears, which is why many modern cultivars are all-male. However, there are also older, non-hybrid cultivars that produce both male and female plants.
All-male cultivars, such as the F1 hybrids that are commonly available, have some advantages over their non-hybrid counterparts. They tend to produce larger, more uniform spears, which are generally considered to be of higher quality than those produced by female plants. They are also less likely to produce seedlings, which can be a nuisance to remove from your garden beds.
On the other hand, non-hybrid cultivars that produce both male and female plants can be a good option for some growers. While the female plants may be less productive than the males, they still produce edible asparagus spears, and they also produce seeds that can be saved for future plantings. However, it’s important to keep in mind that these cultivars require more maintenance, as you’ll need to weed out any unwanted seedlings to prevent them from competing with your established plants.
When choosing a variety of asparagus to grow, there are a few other factors to consider as well. Flavour, colour, spear size, and overall harvest size can all vary between different cultivars, so it’s worth doing some research to find a variety that suits your preferences. Some varieties also produce earlier or later harvests, which can allow you to extend your asparagus season if you grow multiple varieties.
Finally, it’s a good idea to look for varieties that have been awarded the RHS Award of Garden Merit (AGM). This award indicates that the variety has performed well in trials and should be a reliable producer in your garden.
Prepare the Ground
Soil preparation is a crucial step in growing healthy and productive asparagus plants. Before planting, it’s essential to test the soil and make any necessary amendments to ensure optimal growth conditions. Here’s how to prepare the ground for asparagus planting:
The first step is to test the soil to determine its pH level and nutrient content. Testing the soil will help you determine if it’s necessary to adjust the pH level, add nutrients, or improve soil drainage.
Amending Soil pH:
Asparagus thrives in soil with a pH level of 6.5-7.5. If your soil is too acidic, you may need to add lime to raise the pH level. On the other hand, if the soil is too alkaline, you may need to add sulphur to lower the pH level. Follow the instructions on the product label for proper application rates.
Improving Soil Drainage:
Asparagus prefers well-drained soil. If your soil is heavy and clay-like, it’s a good idea to make a raised bed to provide better drainage. To make a raised bed, simply follow the instructions in our Introduction to Raised Bed Gardening.
Adding Organic Matter:
Adding organic matter to the soil is essential for improving soil fertility, water retention, and soil structure. Before planting, dig in at least a bucket full of well-rotted garden compost or manure per square meter of the planting bed. This will help to enrich the soil and provide a good growing medium for the asparagus plants.
Lastly, weed the bed thoroughly before planting to remove any potential competition for nutrients and water. Remove all weeds and their roots from the planting site, and make sure the bed is clean and free of debris.
By following these soil preparation steps, you can create a perfect growing environment for your asparagus plants, which will result in a bountiful harvest for many years to come.
Sow seeds indoors at 13–16°C in February. In each of the small pots or modular trays that have been composted, place one seed. Keep the seedlings warm and well-hydrated in a bright area. Start hardening them off after the last frost, and at the beginning of June, transplant them into their final positions.
Alternately, sow outside in drills 2.5 cm deep and 30–45 cm apart in March or April. Protect the seedlings from slugs and snails by spacing them 15 cm apart. The following March, move them to their final positions on well-prepared ground.
Dig a trench 30cm wide and 20cm deep. Fork garden compost or well-rotted manure into the base, then cover with a 5cm layer of the excavated soil. Make a ridge of soil along the centre of the trench, 10cm high.
Put the crowns on top of this edge, with the growing points or new shoots highest, placing them 30-45cm apart. Spread the roots out uniformly, however handle cautiously as they break easily. Blend organic matter into the soil, then gently return this enhanced soil once again into the trench, leaving the bud tips slightly visible.
Plants should be spaced 45 cm apart between rows and spread out. Water in, then mulch with a 5 cm layer of garden compost or well-rotted manure to get rid of weeds. The bed should be kept weed free, as asparagus develops best without contest from different plants.
Asparagus Plant Care
Asparagus plants need to be fed well and kept free of weeds in order to thrive. Plants should be cut down at the end of the growing season because they may need support as they get tall. Wait for the foliage to turn yellow before cutting all the stems down to the base.
Weeding and removing
Asparagus thrives when there is no competition from other plants in the bed, so keep it free of weeds. Weed by hand rather than using a hoe because of their shallow, easily damaged roots.
Get rid of any seedlings that are produced by female plants. In the event that you’re growing an all-male cultivar, you might in any case find a periodic female plant, which you ought to eliminate.
Newly planted asparagus should be watered regularly throughout their first summer to help establish strong roots. Once established, asparagus plants are drought tolerant and will only need watering during long dry spells. It’s important to avoid overwatering as this can lead to root rot, which can be detrimental to the health of the plant.
In late winter, cover the bed with mulch to keep moisture in the soil and prevent weed growth. To prevent annual weeds from germinating, consider covering the bed with a weed-suppressing membrane from autumn to winter. It is important not to allow weeds to get established.
Mulching is an effective way to discourage weed growth and retain moisture in the soil. Late winter is the ideal time to apply mulch to the asparagus bed. Consider using organic materials like straw, leaves, or grass clippings, as these will gradually break down and provide nutrients to the soil. It’s important to avoid using mulch that is high in nitrogen, as this can lead to excessive foliage growth at the expense of the crop.
Asparagus plants require a good source of nutrients to grow and produce quality yields. It’s recommended to apply a high potassium fertiliser in early spring at a rate of two handfuls per square meter. This will help to encourage healthy growth and improve the overall quality of the crop.
Asparagus plants can grow quite tall and may require support to prevent them from breaking in windy weather. One effective way to support asparagus plants is by creating a fence on either side of the row using stakes and twine. This will help to keep the plants upright and prevent damage to the crown. It’s important to provide support early in the growing season before the stems become too heavy and prone to breaking.
Divide well-established crowns in late winter or early spring to produce additional plants. Do this no more then every three years, as asparagus plants can be slow to settle back in afterwards.
Carefully dig up the crown. Take the strongest parts from the crown’s edge and gently tear it into several smaller sections, each with several growing points. If some roots cannot be separated, cutting them may be necessary. Get rid of any stale, woody plants.
Replant the new sections straight away, with the buds visible at the soil surface.
Harvesting asparagus is a crucial step in the growing process, and it’s important to know how to do it properly to ensure that your asparagus is of the highest quality. Here are some additional tips to help you harvest your asparagus effectively:
- Identifying when spears are ready to be harvested: When harvesting asparagus, it’s important to know when the spears are ready to be picked. Asparagus spears are ready to be harvested when they are about 13cm tall, and their tips are still tight and pointed. If the tips have begun to open up, then the asparagus has passed its prime and should not be harvested.
- How to cut asparagus properly: To harvest asparagus, cut the spear about 2.5cm below the soil surface. This is done using a sharp knife, and care should be taken to avoid damaging neighbouring spears. It’s important to cut the spear cleanly to prevent any damage to the plant, and to avoid leaving any stubble behind that could attract pests or disease.
- How to store harvested asparagus: After harvesting your asparagus, it’s important to store it properly to maintain its freshness and flavour. The best way to store asparagus is to keep it in the refrigerator, either in a plastic bag or standing upright in a jar with an inch or two of water in the bottom. Asparagus should be consumed within a few days of harvesting for the best flavour and quality.
To store asparagus, you will need a glass jar/ drinking glass, paper towels, knife, plastic bag, rubber band (optional), 1 bunch of fresh asparagus and some cold water.
For short term storage (1-2 days), start by wrapping the bunch with a few sheets of damp paper towel and place in a plastic bag. Leave it open so that air can flow through it. Store it in the vegetable or crisper drawer of your fridge as soon as you can.
For long term storage (up to 5 days), start by trimming an inch off the ends of the asparagus stalks using a sharp knife. Then place an inch of water at the bottom of a deep mason jar or a drinking glass. Remove and rubber bands and place the asparagus spears upright (with cut ends at the bottom) into the glass. Place a clean plastic bag over the asparagus and container and tie it loosely using a rubber band, making sure that the spears have enough room for air circulation. For up to five days, store it in the refrigerator, changing the water if it becomes cloudy.
Asparagus grows reliably every spring and generally does not experience many issues. Slugs, snails, and asparagus beetles are the most common pests that can harm plants and reduce harvests. Late frosts can also damage young shoots in spring, and plants are prone to rooting in damp soil.
To prevent and treat these common pests and diseases, there are several steps that can be taken. First, it’s important to keep the asparagus bed clean and free of debris. This can help to reduce the likelihood of pest infestations and fungal diseases.
Regularly inspecting plants for signs of pest or disease damage is also important. If pests are found, consider using insecticidal soap or neem oil as a natural control method. For fungal diseases, avoid overwatering and ensure good air circulation around the plants to prevent moisture build-up.
We recommend the RHS Award of Garden Merit-winning “Ginlim,” “Pacific 2000,” and a late variety called “Guelph Millennium” for asparagus.
One of the few vegetables that can be grown year-round in gardens is asparagus. Cultivating it is relatively straightforward. However, when growing asparagus, you’ll need to be patient.
Ten spears should be produced each season by an established plant. Shoots should be allowed to develop into tall ferny plants throughout the remainder of the summer after the harvesting period. They will then sprout again in the spring, ready for harvesting once more if you simply cut them down to the ground in the fall.
Great companion plants for asparagus are tomatoes. After the asparagus growing season is over, tomatoes will mature into large plants. Asparagus bugs could do without tomato plants so developing tomatoes in a similar bed won’t just use the space yet additionally keep your asparagus plants healthy.
Growing your own asparagus can be a rewarding experience for beginner gardeners, but it requires some patience and careful planning. By choosing the right cultivars, preparing the soil correctly, and providing proper care, you can enjoy a bountiful harvest of delicious asparagus spears for years to come. Remember to be patient during the establishment phase, and avoid harvesting until the plants are well-established. With these tips and techniques in mind, you can confidently grow your own asparagus and enjoy the benefits of this tasty and nutritious crop.