When to plant Begonias in Cass County, MN
Cass County sits in cold Zone 4a. Plant Begonias May 26–June 9 for the single annual harvest; the September 28 first frost closes the window.
When to Plant Begonias in Cass County, MN
Wax begonias (Begonia × semperflorens) are the workhorse shade bedding plant of American horticulture, offering continuous bloom from transplant to hard frost. Bronze or green-leaved varieties perform well from deep shade to full sun (in northern zones) and tolerate summer humidity better than most cool- season flowers. A staple of mass plantings, containers, and window boxes.
Cass County, Minnesota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 28, giving you a growing season of approximately 139 days.
At an elevation of 938 feet, Cass County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Begonias to ensure they mature before fall.
Cass County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Begonias Planting Timeline — Cass County, MN
Begonias Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 24 | Feb 24 – Mar 10 |
| Transplant Outdoors | May 26 | May 26 – Jun 9 |
| Bloom | August 4 | Aug 4 – Oct 6 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: N/A
🗺️ USDA Zone
Zone 4a
📆 Growing Season
139 days in Cass County
Growing Tips for Cass County
Start seeds indoors 10–12 weeks before last frost — seed is dust-fine; surface-sow on moist mix under lights, do not cover. Bottom heat (70–75°F) speeds germination. Transplant after frost; begonias are not direct-sown in practice. Pinch seedlings once for branching. Keep soil evenly moist; avoid waterlogged conditions. Bronze-leaf types tolerate more sun; green- leaf types prefer shade to part-sun.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Begonias in Other Locations
Frequently Asked Questions
When should I plant Begonias in Cass County, MN?
Cass County is in Zone 4a with an average last frost of May 12. Plan your Begonias planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, MN?
Cass County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 28.
When should I plant Begonias in Cass County, MN?
In Cass County, MN, plant Begonias after the last frost (around May 12) and before the first frost (around September 28). Best results when soil holds above 50°F.
What growing zone is Cass County, MN for Begonias?
Cass County sits in USDA Zone 4a. Begonias grows reliably in zones 2a through 11b, so it's a good fit here.
Can Begonias grow in Cass County's climate?
Yes — Begonias grows well in Cass County's temperate climate. Cass County averages a 139-day frost-free season, with last frost around May 12 and first frost around September 28.
Your Cass County Garden Planner — Free
A 22-page printable planner built for Cass County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.