When to Plant Asparagus in St. Louis County, MO
Asparagus is a long-lived perennial vegetable that produces tender spears each spring for 15-20 years once established. It requires patience but rewards with reliable harvests.
St. Louis County, Missouri is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 24, giving you a growing season of approximately 194 days.
At an elevation of 895 feet, St. Louis County receives approximately 40.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Asparagus during the growing season.
St. Louis County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.6
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Plant Water Budget
Asparagus Planting Timeline — St. Louis County, MO
Asparagus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
730–1095 days
Soil pH
6.5 – 7.5
USDA Zone
Zone 6a
Growing Season
194 days
Growing Tips for St. Louis County
Plant crowns in deep trenches with compost. Do not harvest spears for the first two years to allow root establishment. Mulch heavily to suppress weeds and retain moisture.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Asparagus in Other Locations
Frequently Asked Questions
When should I plant Asparagus in St. Louis County, MO?
St. Louis County is in Zone 6a with an average last frost of April 13. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Louis County, MO?
St. Louis County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 24.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help St. Louis County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
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