Vermont asparagus crowns need to settle into cold soil before the ground freezes solid. If you are searching for the best time to plant asparagus in Vermont, the short answer is early spring, as soon as the soil can be worked. This timing gives the crowns a full growing season to establish strong roots before winter returns.
Asparagus is a perennial vegetable that can produce spears for 15 to 20 years once established. Getting the planting window right is the most important step for long-term success in Vermont’s short growing season and cold winters.
Best Time To Plant Asparagus In Vermont
The ideal window for planting asparagus crowns in Vermont is from mid-April to mid-May. You want to plant when the soil temperature reaches about 50°F (10°C) and the ground is no longer waterlogged from snowmelt. Planting too early risks rot in cold, wet soil. Planting too late means the roots won’t have enough time to develop before the first fall frost.
In northern Vermont, near Burlington or St. Johnsbury, aim for late April to early May. In southern Vermont, around Bennington or Brattleboro, mid-April is usually safe. Watch your local frost dates and soil conditions rather than relying on a calendar alone.
Why Spring Planting Works Best In Vermont
Vermont’s winters are long and harsh. Fall planting is risky because young asparagus roots need several weeks of soil temperatures above 40°F to establish before the ground freezes. Spring planting gives the crowns a full season to anchor deep roots.
Spring-planted asparagus also avoids the stress of heaving. Frost heaving can push shallow roots out of the ground during freeze-thaw cycles. By planting in spring, the roots have time to grow deep enough to resist heaving the following winter.
What About Fall Planting?
Some gardeners in warmer states plant asparagus in fall. In Vermont, fall planting is not recomended. The ground often freezes by late November, and young crowns need at least 4 to 6 weeks of growth before dormancy. Vermont’s autumns are too short and unpredictable for this to work reliably.
If you missed the spring window, wait until the following year. Asparagus is a long-term investment, and rushing a fall planting usually leads to failure.
Preparing Your Asparagus Bed
Asparagus beds need careful preparation. This crop stays in the same spot for decades, so getting the soil right before planting is essential.
Choose The Right Location
- Full sun: At least 8 hours of direct sunlight daily.
- Well-draining soil: Asparagus roots rot in standing water. Raised beds work well in Vermont’s clay soils.
- Wind protection: A sheltered spot reduces damage to tall fern growth in summer.
Test And Amend Your Soil
Asparagus prefers a soil pH between 6.5 and 7.5. Vermont soils tend to be acidic, so you may need to add lime. Test your soil in fall or early spring, then amend accordingly.
- Remove all weeds and grass from the bed. Perennial weeds like quackgrass are especially problematic.
- Dig the soil to a depth of 12 to 15 inches.
- Mix in 2 to 3 inches of compost or well-rotted manure.
- Add a balanced fertilizer like 10-10-10 at a rate of 1 pound per 100 square feet.
Dig The Trenches
Plant asparagus in trenches, not individual holes. Dig trenches 6 to 8 inches deep and 12 to 18 inches wide. Space trenches 3 to 4 feet apart. This spacing gives the crowns room to spread and makes weeding easier.
Planting Asparagus Crowns Step By Step
Follow these steps for the best chance of success with your Vermont asparagus bed.
Step 1: Soak The Crowns
Soak bare-root crowns in lukewarm water for 1 to 2 hours before planting. This rehydrates the roots and helps them recover from storage. Do not soak longer than 4 hours, as the roots may become waterlogged.
Step 2: Position The Crowns
Place each crown in the trench with the roots spread out like a fan. The bud side should face upward. Space crowns 12 to 18 inches apart within the trench. Closer spacing gives more spears in early years, but wider spacing leads to larger, healthier plants over time.
Step 3: Cover The Crowns
Cover the crowns with 2 to 3 inches of soil. Do not fill the trench completely at planting time. As the spears grow, gradually add more soil over the next few weeks until the trench is level with the ground. This method prevents the crowns from being buried too deep at once.
Step 4: Water Thoroughly
Water the bed deeply after planting. Keep the soil moist but not soggy for the first few weeks. Once established, asparagus is fairly drought-tolerant, but consistent moisture in the first year is critical.
Caring For First-Year Asparagus
First-year asparagus needs different care than established plants. The goal is to build a strong root system, not to harvest spears.
Do Not Harvest In Year One
Resist the temptation to pick any spears the first year. Let all the spears grow into ferns. The ferns photosynthesize and send energy to the roots. Harvesting too early weakens the plant and reduces future yields.
Weed Control Is Critical
Asparagus does not compete well with weeds. Keep the bed weed-free by hand pulling or using a shallow hoe. Mulching with straw or wood chips after the soil warms up helps suppress weeds and retain moisture.
Fertilize In Late Summer
Apply a light side-dressing of balanced fertilizer in late July or early August. This gives the plants a boost before they start storing energy for winter. Do not fertilize after September, as this can encourage tender growth that gets damaged by frost.
Winter Preparation For Vermont Asparagus
Vermont winters are brutal, but asparagus is naturally cold-hardy. Still, a few steps help protect your bed.
Cut Back Ferns After Frost
Wait until the ferns turn brown and die back after a hard frost. Then cut them down to 2 inches above the ground. Remove the debris from the bed to prevent diseases and pests from overwintering.
Apply Winter Mulch
Cover the bed with 4 to 6 inches of straw, leaves, or wood chips after the ground freezes. This insulates the soil and prevents frost heaving. Remove the mulch in early spring before the spears emerge.
Harvesting In Subsequent Years
Patience pays off. Here is a general timeline for harvesting asparagus in Vermont.
- Year 2: Harvest for 2 to 3 weeks. Pick spears that are 6 to 8 inches tall and still tight at the tip.
- Year 3: Harvest for 4 to 6 weeks.
- Year 4 and beyond: Harvest for 8 to 10 weeks, until spears become thin and spindly.
Stop harvesting when most spears are thinner than a pencil. This signals that the roots need to rebuild energy stores for next year.
Common Vermont Asparagus Problems
Even with perfect timing, issues can arise. Here are the most common problems and how to handle them.
Asparagus Beetles
These small beetles and their larvae chew on spears and ferns. Hand pick them in small beds. For larger infestations, use insecticidal soap or neem oil. Remove old fern debris in fall to reduce overwintering sites.
Frost Damage To New Spears
Late spring frosts can damage emerging spears. If frost is forecast, cover the bed with row cover or old sheets overnight. Damaged spears will turn black and mushy; cut them off and new ones will grow.
Poor Spear Production
If your asparagus bed produces few spears after several years, the soil may be too acidic or lacking nutrients. Test the pH and fertilize in spring. Also check for overcrowding; mature plants may need to be divided every 10 to 15 years.
Varieties That Perform Well In Vermont
Not all asparagus varieties are equal in cold climates. Choose varieties bred for northern conditions.
- Jersey Knight: All-male hybrid, high yielding, disease resistant, cold hardy.
- Jersey Giant: Another all-male hybrid, early season, good for Vermont’s short springs.
- Mary Washington: Heirloom variety, produces both male and female plants, reliable but lower yielding.
- Purple Passion: Purple spears, sweeter flavor, slightly less cold hardy but worth trying in sheltered spots.
When To Plant Asparagus Seeds In Vermont
Most Vermont gardeners plant crowns, not seeds. Crowns are 1-year-old roots that give a 1-year head start. Seeds take 2 to 3 years to reach harvest size. If you want to try seeds, start them indoors in late February or early March, then transplant seedlings outdoors in late May after the last frost.
Seed-grown asparagus is cheaper but requires more patience and care. For most home gardeners, buying crowns is the better choice.
Frequently Asked Questions
Can I Plant Asparagus In Vermont In The Fall?
Fall planting is not recomended for Vermont. The growing window is too short before the ground freezes. Spring planting gives much better results.
How Deep Should I Plant Asparagus Crowns In Vermont?
Plant crowns 6 to 8 inches deep in trenches. Cover with 2 to 3 inches of soil initially, then fill the trench gradually as spears grow.
What Is The Latest Date To Plant Asparagus In Vermont?
Try to plant by mid-May. Planting after June 1 reduces the chances of a strong root system before winter. If you miss the window, wait until next spring.
Do I Need To Water Asparagus In Vermont?
Yes, especially in the first year. Vermont summers can have dry spells. Water deeply once a week if rainfall is less than 1 inch. Established plants need less water.
How Long Does Asparagus Live In Vermont Gardens?
With proper care, an asparagus bed can produce for 15 to 20 years. Some Vermont gardeners report 25-year-old beds still going strong.
Final Tips For Vermont Asparagus Success
Planting at the right time is the foundation, but ongoing care matters just as much. Keep the bed weed-free, fertilize lightly each spring, and never overharvest. Asparagus rewards patience. A well-tended bed will feed your family for decades.
Mark your calendar for mid-April to early May. Check your soil temperature with a simple thermometer. When the ground is workable and not muddy, it is time to plant. That is the best time to plant asparagus in Vermont, and it is worth the wait.