When to Plant Asparagus in Keweenaw County, MI
Your May game plan for Keweenaw County, Michigan
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Keweenaw County, Michigan.
To set up a strong June, finish these tasks
- Transplants going out: asparagus
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.
Keweenaw County, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.
At an elevation of 1,035 feet, Keweenaw County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Asparagus to ensure they mature before fall.
Keweenaw County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.9
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.
Soil Compatibility in Keweenaw County
How your county's soil matches Asparagus's growing requirements.
Soil pH
Your soil pH (6.1–6.9) overlaps with Asparagus's range (6.5–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Keweenaw County is excellent for Asparagus — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — Asparagus will thrive.
How to Plant Asparagus
Plant Water Budget
Monthly Watering Guide for Asparagus
Asparagus needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Asparagus Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 3.7" | 0" | ❄️ Dormant |
| May | 3.5" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 5" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 4.7" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 3.7" | 0" | ✅ Rainfall sufficient |
| Oct | 3.5" | 3.2" | 0.3" | 💧 Light watering |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Keweenaw County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Asparagus Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Asparagus Planting Timeline — Keweenaw County, MI
Asparagus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 2 | Jun 2 – Jun 16 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Natural rainfall sufficient
📅 Days to Maturity
730–1095 days
🧪 Soil pH
Needs 6.5–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
135 days in Keweenaw County
Growing Tips for Asparagus in Keweenaw County
Direct sow Asparagus outdoors after May 19 in Keweenaw County when soil has warmed and frost danger has passed.
Your 135.0-day growing season in Keweenaw County is tight for Asparagus (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Asparagus in Other Locations
Frequently Asked Questions
When should I plant Asparagus in Keweenaw County, MI?
Keweenaw County is in Zone 5b with an average last frost of May 19. Plan your Asparagus planting based on this frost date — see the calendar above for exact timing.
What planting zone is Keweenaw County, MI?
Keweenaw County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 1.
Your Keweenaw County Garden Planner — Free
A 24-page printable planner built for Keweenaw County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.