One of the first plants that usher in the spring season is asparagus. This tasty veggie is known for its slender spears and versatility. So, if you’re planning to grow some for yourself, when’s the best time to plant?
The best time to plant asparagus seeds is from late February to early March. When planting asparagus seeds, it’s best to first grow them in pots indoors before transferring them to a permanent bed. Asparagus take 3yrs to begin producing, but you can plant aged asparagus crowns to speed this up.
Luckily, asparagus is a perennial vegetable that produces year after year. Let’s take a close look at when to plant, grow, and harvest asparagus. We’ll also highlight the crops that grow well with this slender veggie.
When Should You Plant Asparagus Seeds?
The ideal time to start planting asparagus seeds (on Amazon) is late February or early March. We also recommend planting these seeds indoors initially because the seeds may be too fragile to survive in a permanent bed outdoors.
Afterward, sow the seeds in a plant pot and place them near a window facing the sun. The following spring, after the seedling has grown and reached a height of about a foot, you can transplant it into a permanent plant bed.
Another popular method of cultivating asparagus is from 1-year-old crowns. Most gardeners prefer this method for two reasons: because it speeds up overall production, and because there are fewer weeds with this process. That said, you can get 2-year-old crowns (on Amazon) to speed up the production of your plants (more on that later).
We recommend planting asparagus crowns as soon as you till the soil in the early spring. Many farmers plant asparagus around the same time that potatoes are grown.
The harvest season lasts for 6 to 8 weeks, from early May to late June. Asparagus spears grow up to 2 inches daily during peak season, providing gardeners with plentiful harvests.
How to Plant Asparagus
Planting asparagus involves some crucial steps to ensure the veggies grow correctly. Begin by digging a plant bed roughly 12 inches wide and 6 to 8 inches deep. Then, create a 2-inch ridge in the middle of the bed, place the crowns on top, and spread the roots evenly.
Afterward, place the asparagus crowns inside, cover the crowns with compost and bury them 2 inches underground. We recommend that you soak the asparagus crowns for 10 to 20 minutes before planting.
Once the crowns are covered, pour water on them, then wait until the spears grow about 3 inches tall. As the spears reach 3 inches in height, add 2 inches of soil to the plant bed. Make sure you don’t completely bury the spears. Don’t forget to maintain a 12- to 15-inch gap between crowns.
As soon as the spears grow above the soil layer again, add another 2-inch layer of soil. Repeat this procedure until you fill-up the plant bed. Once you fill the bed, pile the soil slightly to stop water from accumulating around the spears.
Alternatively, you can skip gradually adding layers of soil and instead plant the asparagus crown in a bed and fill it to ground level with compost and soil. This planting method is less detailed, but some farmers claim this method produces similarly impressive spears.
As long as the soil is relatively loose, the asparagus spears should have no issues pushing through the soil.
How Deep to Plant Asparagus Crowns
We recommend planting asparagus crowns in plant beds that are 12 inches wide and 6-8 inches deep. It’s important not to plant these crowns too deep so they don’t take too long to break through the ground. Furthermore, arrange the crowns 12-15 inches apart and add 2 inches of topsoil.
Where Should Asparagus Be Planted?
It would be best to plant asparagus in a fertile, properly drained location with soil that retains moisture. Late spring frosts damage emerging spears, so choose an area that won’t expose them to it.
Furthermore, asparagus roots are deep, so it’s recommended to avoid spots with shallow soil or soils prone to flooding. In a vegetable garden, growing asparagus at the northern end is the best option. This way, the tall ferns don’t overshadow the asparagus.
Should You Soak Asparagus Crowns Before Planting?
Soaking asparagus crowns before planting is very beneficial to the plant. This process hydrates the plant before it enters the soil. To do this, soak the asparagus crowns in water for 10-20 minutes. You can also soak the crowns in organic compost tea to hasten the growth.
What Type of Soil Does Asparagus Like?
Asparagus thrives best in well-drained soils with a pH of 6.5 to 7.0 and will not grow in very acidic soils.
This plant can grow in light, medium, or heavy soils as long as the soil is well-drained and doesn’t collect water after rain. Asparagus doesn’t like excessive moisture, so ensure you choose a suitable planting spot. You can also expect good results if you plant asparagus on very sandy soil.
How to Grow Asparagus
Once you’ve followed our instructions on planting asparagus, here’s some more information on how to grow them successfully.
- After filling the bed, we recommend adding 4-6 inches of mulch.
- The most challenging aspect of growing asparagus is dealing with weeds in the first two years. Note that you shouldn’t disturb the asparagus’ roots, so ensure you pull out the weeds gently.
- Add compost to the plant to keep soil moisture and weeds at bay. Asparagus plants need 1-2 inches of water per square foot weekly for the first two years after planting. If you don’t get enough rain, ensure you supply enough water.
- Asparagus requires a consistent plant food supply to thrive. So, during the growing season, consider using an organic fertilizer.
If you must transplant asparagus, do so in early spring when the plants are dormant — or in late fall before the first frost. Use a garden fork to dig and lift crowns while being careful not to damage or remove the roots.
How Long Does Asparagus Take to Grow?
Asparagus takes three years to grow; however, certain factors like soil quality can hasten or delay the maturity period. Three years may seem to be a long time for a vegetable crop, but once the initial years of growth are complete, the plant will produce new asparagus spears yearly for the next two decades.
Waiting before harvesting asparagus results in stronger roots that grow better spears in the subsequent years.
Asparagus Growing Stages
Here are the five growth stages of asparagus:
- Stage 1: The asparagus crown shoots up spears during the spring of the first and second years.
- Stage 2: Asparagus spears emerge from the soil steadily throughout the season during the third spring. The spears are ready for harvest when they’re green and 25 cm or longer.
- Stage 3: The cut spears are then collected in bundles and moved to where they’re needed.
- Stage 4: The spears in the soil are left to grow into ferns at the end of the season. This stage is crucial for the plant because it’s when the crown regenerates for the next growing season.
- Stage 5: The asparagus fern dies around May, and the fern debris is mulched back into the soil. The crown remains dormant until the following spring and begins growing once more.
How to Harvest Asparagus
After successfully growing asparagus, it’s time to harvest it. It is best to avoid harvesting in the first and second years. Wait at least three growing seasons before you start harvesting to allow the crowns to grow fully.
Harvest the spears when they’re roughly 10 inches tall and as thick as your pinky finger. Note that thinner spears will most likely be more tender. Furthermore, harvest the asparagus spears before their flower buds open.
Once you’re sure the plant is ready for harvest, cut the asparagus spears at ground level with sharp garden scissors or asparagus knives. An asparagus knife (on Amazon) is perfect for this task because it’s specially designed to cut the plant where it’s most tender.
After harvesting, we recommend fertilizing the asparagus plant in early summer. To do so, dress the topsoil with nutrient-rich compost or organic fertilizer (on Amazon). Note that you will destroy the plant bed if you cut off the remaining ferns during summer. Only prune asparagus ferns after the foliage turns yellow or brown.
Leave the ferns to mature so they replenish the nutrients in the soil to facilitate spear production the following year. Lastly, ensure you leave a minimum of two spears on the asparagus patch to maintain its fertility.
How to Store Asparagus
Once harvesting is complete, immerse the freshly cut spears in cold water to retain their sugar content. It’s crucial to store asparagus after harvest because they taste best as soon as you harvest them and don’t typically last long.
So, if you want to increase the shelf life of your asparagus, trim the bottom of the spears and place them in a jar filled with about one inch of water. Then, cover the jar with a plastic bag and place it in the fridge for up to 4 days. Consider changing the water as soon as it appears white to keep the asparagus perky and fresh.
However, if you don’t have enough space in your fridge, wrap the spears in damp paper towels and place them in a plastic bag before refrigerating.
What Grows Well With Asparagus?
Companion planting is an excellent way of maintaining asparagus. Herbs and vegetable plants are the most commonly used companion plants in gardens. On the other hand, flowering ornamentals are a perfect addition due to their bright bursts of color that attract helpful pollinators.
Herbs
- Basil: Basil is an ideal growing companion for asparagus in your garden. Its aromatic compounds repel asparagus, beetles, flies, and mosquitos, limiting the need for chemical pesticides.
- Dill: The aroma of the dill plants deters some of the troublesome insects. Their long taproots mean they don’t compete for nutrients with asparagus.
- Comfrey: Comfrey defends against fungal diseases and rust. It also attracts pollinators, which increase fertilization, and it attracts beneficial parasitic wasps, which attack asparagus parasites.
- Parsley: The natural aroma of parsley acts as a natural pest repellent while also encouraging certain helpful insects that prey on harmful species.
- Sage: Sage’s intense flavor and aroma deter some pests. Sage, like asparagus, returns year after year if properly cared for.
Fruits & Vegetables
- Eggplant: This plant is one of the best companions for asparagus. Eggplants prevent the destructive asparagus beetle from destroying the asparagus spears. Moreover, eggplants contain solanine, a highly effective pesticide compound.
- Lettuce: Lettuce and asparagus make excellent companion plants because the asparagus provides shade to the lettuce plants during hot weather. Furthermore, lettuce inhibits weed growth, and its tall fronds keep the soil temperature low.
- Spinach: Spinach is another crop that grows well with asparagus. The spinach will conveniently grow alongside your spears, keeping weeds at bay. Then, later in the season, the fronds of the asparagus will cast shade over the spinach to cool it down.
- Strawberry: Asparagus enjoys growing beside strawberries, and they make an excellent companion. They both start growing after the last frost in the spring. Furthermore, strawberries and asparagus root systems grow in different planes in the soil. Therefore, there’s not too much competition for resources, and you can be sure that both these plants will grow properly. Strawberries also help to shade the soil and keep weeds at bay.
- Tomato: Tomatoes make an excellent pest-control companion plant for asparagus. Tomato leaves are very aromatic, which helps repel pests and is one of the best natural repellents of asparagus beetles. Furthermore, tomato root systems grow deep, so they don’t compete with the asparagus for nutrients.
Flowering Ornamentals
- Asters: Daisy, sunflower, and coneflowers are members of the aster family. These flowers make excellent companion plants because they naturally repel most insect pests. Aster plants are also disease-free and can grow in various conditions with little attention.
- Marigold: These plants have a naturally pungent aroma that deters pests. The plant also has a compound called phytotoxin, which repels soil nematodes.
- Nasturtium: Nasturtium plants complement asparagus by stopping pests and shading weeds. Nasturtium plants also attract pollinators, which increase yields, and hover flies, which prey on pest insects like aphids.
Plants That Don’t Grow Well With Asparagus
Just as there are excellent planting companions for asparagus, there are some plants that you shouldn’t grow with asparagus. Here are plants that are incompatible with asparagus:
- Potatoes: When you plant asparagus and potatoes in the same space, asparagus stunts potato growth. This is because potatoes and asparagus compete intensely for soil resources. Therefore, we recommend planting these plants in different beds.
- Alliums: Alliums — like garlic, leeks, and onion — stunt the growth of asparagus. So, it’s best to plant these crops far away from the asparagus plant.
How Do You Winterize Asparagus?
Asparagus needs to be winterized yearly, starting from the fall after planting. Winterization shields the plant’s roots from the cold and encourages dormancy so the asparagus can rest before the next productive growth cycle in spring.
- Step 1: Once the leaves become yellow in fall, cut back the stalks to ground level. Remove withering stalks and leaves from the bed and discard them or use them as compost.
- Step 2: After you’ve cut the asparagus stems, stop watering them. Asparagus crowns go dormant in the winter and don’t require watering during this season.
- Step 3: After cutting back the old stalks, disperse 2 inches of mulch over the plant bed. Consider using wood chips or straw to shield the crowns from the low winter temperatures.
- Step 4: When the shoots emerge in the spring, remove or compost the old mulch. Mulch left on the asparagus bed during the winter can harbor fungal disease or rust, damaging the asparagus roots.
Conclusion
Asparagus is a crop that you can plant with seeds or crowns. We recommend sowing the seeds early in the year, during February or March. For the best results, plant asparagus crowns while the soil is still warm from the summer heat.
The roots adapt to the soil bed a little during this time and wake up before winter begins. Consider planting asparagus with one of the companion plants we highlighted for larger yields. Growing asparagus takes some time, but it’s well worth it!