When to plant Borage in Union County, IA
For Borage in Union County, the safe spring window opens around April 9 and closes around April 30. Last expected frost is April 23, first fall frost October 11, giving a 171-day growing season. A second sowing from August 2 to August 16 extends the harvest into fall.
When to Plant Borage in Union County, IA
Borage is a self-seeding annual herb with star-shaped blue flowers that attract pollinators. Its leaves have a cucumber-like flavor and the flowers are edible.
Union County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.
At an elevation of 1,311 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Borage to ensure they mature before fall.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Borage Planting Timeline — Union County, IA
Borage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Harvest | June 11 | Jun 11 – Jul 30 |
| Fall Sowing | August 2 | Aug 2 – Aug 16 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
50–60 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
171 days in Union County
Growing Tips for Union County
Direct sow in spring as borage does not transplant well. Allow some plants to go to seed for next year. Young leaves are best; older leaves become bristly.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Borage in Other Locations
Frequently Asked Questions
When should I plant Borage in Union County, IA?
Union County is in Zone 5b with an average last frost of April 23. Plan your Borage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, IA?
Union County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 11.
When should I plant Borage in Union County, IA?
In Union County, IA, plant Borage after the last frost (around April 23) and before the first frost (around October 11). Best results when soil holds above 50°F.
What growing zone is Union County, IA for Borage?
Union County sits in USDA Zone 5b. Borage grows reliably in zones 3a through 11b, so it's a good fit here.
Can Borage grow in Union County's climate?
Yes — Borage grows well in Union County's temperate climate. Union County averages a 171-day frost-free season, with last frost around April 23 and first frost around October 11.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union 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.