Asparagus is a spring delicacy, holds a special place in the hearts of gardeners and food enthusiasts alike. Its spears have a distinct flavour making it a prized vegetable in many cuisines. While asparagus takes a bit of patience and care to grow, the reward of harvesting your very own spears is well worth the effort. The following will equip you with enough knowledge to cultivate a thriving asparagus patch in your own backyard.
Selecting the Right Variety
Choosing the right asparagus variety is the first step towards a successful harvest. Two main types available are: green and purple.
Green asparagus is the most common and suited to a wider range of climates. Purple asparagus tends to be sweeter and is an excellent choice for those with milder climates. Varieties such as Mary Washington, Jersey Knight, and Purple Passion are common choices among home gardeners.
Climate and Temperature
Asparagus thrives in temperate climates. It requires a period of dormancy during winter, followed by a cool spring and warm summer to produce robust spears. The ideal temperature range for asparagus growth is between 60°F (15°C) and 85°F (29°C). Extremely hot or cold temperatures can negatively impact the plant's development and yield, although I have known asparagus plants to cope with freezing conditions during the winter.
Sunlight
Asparagus is a sun-loving plant and requires full sun exposure to thrive. Choose a location in your garden that receives at least 6-8 hours of direct sunlight per day. Insufficient sunlight can lead to weak and spindly spears.
Soil Type and Drainage
Asparagus prefers well-drained, fertile soil that is rich in organic matter. The soil should have good moisture retention while allowing excess water to drain away. Sandy loam or loamy soil with a pH level between 6.0 and 7.5 is ideal. Avoid heavy clay soils that can become waterlogged and hinder root development.
Planting Asparagus Crowns
Asparagus is usually grown from crowns, which are 1 to 2 year old dormant plants with well developed root systems. The best time to plant asparagus crowns is in early spring when the soil is workable. The following steps should be followed to give the best chance of growing strong and healthy asparagus plants:
- Dig a trench that is 6-12 inches deep and about 12-18 inches wide.
- Create a small ridge of soil in the center of the trench.
- Place the crowns on top of the ridge, spacing them about 12-18 inches apart.
- Spread the roots over the sides of the ridge and cover them with 2-3 inches of soil.
- Gradually fill the trench with soil as the asparagus grows, but avoid burying the emerging spears.
Watering and Mulching
Consistent moisture is vital for asparagus, particularly during the establishment phase - water the plants regularly. Mulching around the plants with straw, wood chips, or compost can help retain moisture, suppress weeds, and regulate soil temperature.
Proper Care and Maintenance
To ensure healthy growth and a good harvest, provide your asparagus plants with the following care:
- Fertilising
Asparagus plants are heavy feeders. Apply a balanced fertilizer in early spring and again after harvest.
- Weed Control
Regularly weed the asparagus bed to prevent competition for nutrients and space. - Pest and Disease Management
Asparagus is relatively resistant to pests and diseases. However, Monitor your plants regularly for signs of pests or diseases and take appropriate measures, such as handpicking insects or using organic insecticides when necessary. Practice crop rotation and remove any affected plants promptly to prevent the spread of diseases. - Fern Maintenance
After the harvest season, allow the asparagus spears to grow into feathery ferns. These ferns capture sunlight and store energy for next year's harvest. Depending on your garden structure, you may need to design a way of supporting the ferns, but if you have the space, there is no need for this.In late fall after the ferns have died back, trim them to a few inches above the ground.
Harvesting Asparagus
Patience is key when it comes to harvesting asparagus. I would recommend refraining from harvesting spears during the first two years to allow the plants to establish a strong root system.
In the third year, harvest spears that are around 6-8 inches tall, using a sharp knife or asparagus harvesting tool. Cut the spears just below the soil level, being careful not to damage emerging ones. Harvest over a 4-6 week period, allowing the remaining spears to develop into ferns. During following years, you can harvest for up to 10 weeks.
Frequently Asked Questions (FAQs)
The best time to plant asparagus is in early spring when the soil is workable. Asparagus crowns should be planted as soon as the ground can be worked, typically when soil temperatures reach around 50°F (10°C).
Dig a trench that is 6-12 inches deep and about 12-18 inches wide. Place the asparagus crowns on top of a small ridge in the center of the trench, spreading the roots over the sides. Cover the crowns with 2-3 inches of soil initially, gradually filling the trench with soil as the asparagus grows.
Space the asparagus crowns about 12-18 inches apart within the trench. This allows each plant enough space to develop a healthy root system and produce robust spears.
Asparagus plants are generally not harvested for the first two years after planting. This allows the plants to establish a strong root system. In the third year, you can start harvesting spears, and the harvest season usually lasts for about 4-6 weeks.
During the growing season, it's important to provide proper care for your asparagus patch. This includes regular watering to keep the soil evenly moist, fertilizing with a balanced fertilizer in early spring and after harvest, and keeping the bed free of weeds. It's also essential to monitor for pests and diseases and take appropriate measures to address any issues that arise.
While it is possible to grow asparagus in containers, it can be challenging because asparagus plants have deep root systems. If you choose to grow asparagus in containers, make sure the container is at least 18 inches deep and wide to accommodate the roots. Use a well-draining potting mix, and be prepared to provide extra care and maintenance to meet the plant's requirements.
Asparagus plants are perennial and can live for many years if properly cared for. With proper maintenance and management, an asparagus patch can remain productive for 15-20 years or even longer.
Common pests that can affect asparagus include asparagus beetles, slugs, and snails. Asparagus can also be susceptible to diseases such as rust and fusarium wilt. Regular monitoring, practicing good hygiene, and taking appropriate measures such as handpicking insects or using organic insecticides can help manage these issues effectively.
You should stop harvesting asparagus spears once they become thin and spindly, indicating that the plant's energy reserves are being depleted. Allow the remaining spears to grow into ferns and photosynthesize to replenish the plant's energy for the next growing season.
