If you’re like most people I know, you rarely eat anything because of its nutritional or health benefits, but rather because of how it tastes. Or at least, that’s the first consideration.
However, for some vegetables like the elegant asparagus (Asparagus officinalis), you don’t have to worry about your motivation because you’ll get a taste of both worlds.
There’s only one problem – asparagus is quite pricey!
That’s probably why you’re interested in learning how to grow asparagus at home besides harvesting and utilizing it fresh. Besides, asparagus plants have a special delicate flavor when grown locally.
Therefore, if you’re willing to put in the upfront effort and a bit of patience over the first two years, there’s no reason why you can’t have a bountiful harvest every year.
Growing Asparagus from Crowns
Variety selection
Asparagus is a dioecious plant, meaning that the plants can be male or female. Now, if your objective is to grow and harvest the seeds, it would make sense to plant female asparagus, while male plants are preferable for harvesting the spears for consumption.
Understanding this concept is key for various reasons. First, female asparagus plants grow larger and fewer spears yearly because too much energy is spent on seed production. Male plants, on the other hand, produce a great number of small and uniform spears.
Sidenote: Spears are technically the immature stems and are the edible part of the asparagus plant.
However, there are different hybrid varieties to choose from. Most of those varieties don’t produce seeds, live longer, and produce more spears.
Great examples include Purple Passion (purple asparagus), Mary Washington (Common green asparagus), and Apollo (white asparagus when blanched). While these are excellent varieties to start with, there are plenty more available commercially.
Site location and preparation
Once you’ve selected a suitable variety for your specific locale, it’s time to decide where to plant it. Remember, this is a long-term crop that will stay in the same location for up to 15 years. Therefore, the growing location is important.
Asparagus prefers a fertile, sunny, and well-drained site with soil that holds moisture well. In case you have limited space, consider constructing raised beds to plant them in.
To prepare the site, start by collecting soil samples and having them tested in a reputable lab. Make sure to follow all the recommendations from the soil report. Furthermore, you can condition your soil further by incorporating organic manure at least two (2) weeks before planting.
Planting the asparagus crowns
Begin by digging a 6-12-inch-deep furrow (trench) for the crowns to be planted in. In heavy clay soils, dig the furrows shallower (6-8 inches) and deeper (10-12 inches) for very sandy soil. As the soil is removed from the trench, set it aside. It will be returned to the trench several weeks later as the ferns grow.
If planting multiple rows, space the furrows at least 3 feet apart because the plants will spread as they age.
To plant the crowns, place them "head-to-toe" (bud-to-root tip) in a line down the furrow so that the buds of the crowns are spaced about 12 inches apart.
Adding a fertilizer containing phosphorus and potassium to the furrows when planting will help ensure the plants access adequate nutrients as they grow.
Next, cover the crowns with 2-3 inches of the soil that was removed from the furrow. The remaining soil will be added to the trench a few weeks later once the ferns have emerged and grown. Do not let the crowns dry out between placing them in the furrows and covering them with soil. Water immediately after planting.
After planting, there should still be plenty of soil along the sides of the furrows, which will be used later in the season to continue back-filling the furrows as the ferns grow.
Small, narrow spears will emerge from the soil within 2 to 3 weeks of planting, depending on precipitation, temperature, and amount of soil cover. Once the spears are sturdy and several inches tall, several more inches of soil can be backfilled into the furrow. Use caution with this step, as large clods of dry soil can break the brittle spears.
Growing Asparagus from Seeds
You can sow asparagus seeds in a nursery bed, where they’ll take one year to become crowns that you can transplant to a permanent location, as described above.
A few things to remember:
- Filter the seedbed from the scorching sun (use a shade net where possible).
- Mulch to conserve moisture and suppress weeds' emergence.
- Water frequently to prevent the nursery bed from drying out, leading to poor germination.
- Plant the seeds preferably in Spring in rows 1 foot apart and 3 inches from one seed to the next.
Stop watering at least 2 to 3 days before transplanting the seedlings (crowns). This will help in hardening them up. Also, you should dig up the crowns with as much of the root system as you can.
Growing Asparagus from Scraps (Cuttings)
While not the most effective method, you can still grow asparagus from your leftovers (scraps).
Begin by selecting relatively fresh scraps for a high growth success rate. Wash any dirt off and make fresh cuts. Propagate the cuttings in a water jar for rooting before transferring to the soil. Make sure there’s a dense root mass before planting in the soil.
The advantage of this method is that rooting hormone isn’t necessary. You just need to keep changing the water periodically to control pathogen build-up.
Here’s a list of the most common plants to grow in water.
Key tips for maintenance and care
Fertilizer application and nutrition
Asparagus plant nutrition is vital for the formation of healthy spears for harvesting. Therefore, keep collecting and testing your soil for any deficiencies. This way, you’ll be able to take corrective measures in good time.
One of the elements that get depleted quite often is Phosphorus. Nitrogen is also important since it’s responsible for the growth and development of the ferns.
When the crop is full of foliage, the root zone expands, which in turn produces more spears to be harvested subsequently.
Application of a nitrogen-based fertilizer such as 30:3:3 when the spears begin to emerge is ideal.
Watering
The good news is asparagus needs to be watered keenly only when young (their first year after planting). For the remaining period, it can withstand prolonged periods of drought.
Therefore, you’ll need to water when it’s necessary and even much less if you’ve done your mulching right.
Mulching
Applying a thick layer of mulch will help to keep the weeds in check while conserving moisture. Again, as the crop grows, it will form a shade layer beneath, smothering any weeds.
Weeds control
Image credit: University of New Hampshire
When the asparagus plantation is dormant, some people would rather cut it back, which exposes the soil (asparagus bed). This exposure creates a conducive environment for annual weeds to germinate. If left unattended, they could take over the yard.
It’s, therefore, important to weed out any undesired plants in those beds. When weeding, be careful not to damage the shallow asparagus roots.
You can employ several strategies to get rid of weeds, such as mulching, which we’ve discussed, planting cover crops (groundcovers), cultivating (be careful), and hand-removal in small home gardens.
Besides, look out for female asparagus seedlings and remove them as well.
Support
Asparagus grows into a tall, feathery plant over the summer.
To prevent the stems from breaking in windy weather, which could damage the crown, support plants using stakes and twine to make a ‘fence’ on either side of the row.
You could also add netting, secured to the stakes about 50cm (20in) from the ground, for extra support.
Pests and diseases management
When the growing conditions are right, you shouldn’t have to worry about pests and diseases. But there are instances where, regardless of your best effort, the plants become infested and or infected.
The most common asparagus pests include the following:
- Cutworms (Cuts asparagus spear from the ground)
- Asparagus beetles (Causes scarring on the spears)
- Aphids (Infest and colonize the ferns, forming a black sooty mold) – Learn how to get rid of aphids permanently and naturally.
The diseases
- Asparagus rust
- Purple spots
- Crown rot
The best management practices are to regularly scout and monitor the crop for any problems and take corrective measures early enough. But most importantly, keep the crop clean, and you won’t have to worry about pests and diseases.
Harvesting
All along, you’ve been looking forward to the first harvest. As excited as you may be for those first fresh spears emerging from the ground, you shouldn’t touch them for the first two years after planting the crowns. Three if you started from the seeds.
This period is vital to develop a strong crop.
If it’s after the long wait, however, you should deservedly harvest your asparagus but for only two weeks in the first year. The rest of the spears will form the ferns to power up your crop for subsequent years.
Later on, you’ll be free to harvest your asparagus for up to 8 weeks.
To harvest, cut individual spears with a sharp knife 2.5cm below the soil surface when they’re no more than 18cm tall or about finger thickness.
Remember, regular harvesting encourages the production of more shoots – which means more veggies on the table!
Conclusion
Asparagus is a unique crop since it’s one of the few perennial vegetables grown for its delicious and juicy spears. While buying them at a grocery is a viable option, the cost is not always sustainable. Even if it was, they can’t taste as awesome as freshly harvested ones.
You’ve read how you can grow an endless supply of asparagus from crowns that you can order online, seeds, and even scraps from your kitchen.
I hope this guide has been helpful in your sustainable endeavors.
Resource