When to plant Sweet Alyssum in Houghton County County,
Houghton County County's short 136-day growing season means one Sweet Alyssum planting between May 5 and May 26. No fall crop in Zone 5b.
When to Plant Sweet Alyssum in Houghton County, MI
June to-do list for Houghton County, Michigan
Here's what deserves your attention in Houghton County, Michigan this month. Everything below is tailored to Zone 5b and timed around your local frost dates.
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Collect sweet alyssum at their peak
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Coming up in July — start thinking about
- Starting indoors: sweet alyssum
- First harvests: sweet alyssum
Sweet Alyssum (Lobularia maritima) is a low-growing cool-season annual prized for its honey-scented clusters of tiny white, pink, or purple flowers. A workhorse border plant, it tolerates light frost, self-seeds readily, and attracts beneficial insects throughout its bloom season. In warm climates it often re-blooms in fall after summer heat fades.
Houghton County, Michigan is in USDA Zone 5b. The average last spring frost is May 19 and the first fall frost is October 2, giving you a growing season of approximately 136 days.
At an elevation of 956 feet, Houghton County receives approximately 34.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Alyssum to ensure they mature before fall.
Houghton County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.2
Drainage
Well Drained
Sweet Alyssum 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 Houghton County
How your county's soil matches Sweet Alyssum's growing requirements.
Soil pH
Your soil pH (5.9–7.2) overlaps with Sweet Alyssum's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Houghton County is excellent for Sweet Alyssum — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Sweet Alyssum.
How to Plant Sweet Alyssum
Succession Planting Sweet Alyssum
Sow every 5.1 weeks. Last sowing by Aug 03 to harvest before frost.
Sweet Alyssum Water Budget
Monthly Watering Guide for Sweet Alyssum
Sweet Alyssum needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Sweet Alyssum Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 3.6" | 0" | ❄️ Dormant |
| May | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.2" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Houghton County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sweet Alyssum 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.
Sweet Alyssum Planting Timeline — Houghton County, MI
Sweet Alyssum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 31 | Mar 31 – Apr 14 |
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
| Direct Sow | May 5 | May 5 – May 26 |
| Bloom | June 30 | Jun 30 – Sep 8 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
136 days in Houghton County
Growing Tips for Sweet Alyssum in Houghton County
Direct sow Sweet Alyssum outdoors after May 19 in Houghton County when soil has warmed and frost danger has passed.
Common pests for Sweet Alyssum in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Surface-sow seeds — they need light to germinate. Direct-sow as soon as soil can be worked in spring; in zones 7+ also sow in fall. Thin to 6 inches apart. Shear back hard in midsummer when heat causes dormancy — plants recover and re-bloom when cool weather returns. Self-seeds prolifically; allow a few plants to set seed for a perpetual colony.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Sweet Alyssum in Other Locations
Frequently Asked Questions
When should I plant Sweet Alyssum in Houghton County, MI?
Houghton County is in Zone 5b with an average last frost of May 19. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Houghton County, MI?
Houghton County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is May 19 and first fall frost is October 2.
When should I plant Sweet Alyssum in Houghton County County, ?
In Houghton County County, , plant Sweet Alyssum after the last frost (around May 19) and before the first frost (around October 2). Best results when soil holds above 50°F.
What growing zone is Houghton County County, for Sweet Alyssum?
Houghton County County sits in USDA Zone 5b. Sweet Alyssum grows reliably in zones 3a through 11b, so it's a good fit here.
Can Sweet Alyssum grow in Houghton County County's climate?
Yes — Sweet Alyssum grows well in Houghton County County's temperate climate. Houghton County County averages a 136-day frost-free season, with last frost around May 19 and first frost around October 2.
Your Houghton County Garden Planner — Free
A 22-page printable planner built for Houghton 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.