When to plant Foxglove in Sioux County County,
In Zone 5a (Sioux County County), direct-sow Foxglove between May 15 and June 5 for spring, after the May 1 last-frost mark.
When to Plant Foxglove in Sioux County, IA
This month in Sioux County, Iowa
Your Sioux County, Iowa garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
July will be here before you know it — start on
- Starting indoors: foxglove
- First harvests: foxglove
Foxglove (Digitalis purpurea) is a stately cottage garden classic, sending up dramatic 3–5 foot spires of tubular flowers — spotted purple, pink, white, or cream — in late spring and early summer. Technically biennial (flowering in its second year), foxglove perpetuates itself so freely from self-sown seed that established plantings appear to be permanent perennials. A key source plant for the heart medication digitalis, all parts are highly toxic if ingested. Bumblebees are the primary pollinators, crawling deep into each bell-shaped flower. Partial shade and cool, moist woodland-edge conditions suit foxglove best; it resents heat and drought.
Sioux County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 3, giving you a growing season of approximately 155 days.
At an elevation of 1,212 feet, Sioux County receives approximately 39.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Foxglove to ensure they mature before fall.
Sioux County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-7
Drainage
Well Drained
Foxglove 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 Sioux County
How your county's soil matches Foxglove's growing requirements.
Soil pH
Your soil pH (6.3–7.0) is more alkaline than Foxglove prefers (5.5–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The silt loam soil in Sioux County is excellent for Foxglove — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — Foxglove will thrive.
How to Plant Foxglove
Succession Planting Foxglove
Sow every 9.1 weeks. Last sowing by Jun 05 to harvest before frost.
Foxglove Water Budget
Monthly Watering Guide for Foxglove
Foxglove needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Foxglove Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 3" | 0" | ❄️ Dormant |
| Apr | — | 4" | 0" | ❄️ Dormant |
| May | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4" | 0.3" | 💧 Light watering |
| Aug | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Sep | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Oct | 4.3" | 3.3" | 1" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sioux County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Foxglove 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.
Foxglove Planting Timeline — Sioux County, IA
Foxglove Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 27 | Feb 27 – Mar 13 |
| Transplant Outdoors | May 15 | May 15 – May 29 |
| Direct Sow | May 15 | May 15 – Jun 5 |
| Bloom | July 10 | Jul 10 – Aug 21 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Direct Sow |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 5.5–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
155 days in Sioux County
Growing Tips for Foxglove in Sioux County
Direct sow Foxglove outdoors after May 01 in Sioux County when soil has warmed and frost danger has passed.
General growing tips
Sow seeds indoors 8–10 weeks before last frost or direct-sow outdoors in late spring/early summer for next-year bloom (biennial cycle). Surface-sow — seeds need light to germinate. Transplant after last frost into cool, moist, well-amended soil. Morning sun with afternoon shade is ideal; full shade reduces bloom but is tolerated. Keep consistently moist. First-year plants form a basal rosette only; second-year plants produce flower spikes. After bloom, cut the main spike before seed scatters to prevent excessive spreading, or leave some spikes to self-seed for naturalizing. Perennial species (D. grandiflora, D. x mertonensis) maintain clumps without requiring self-seeding. Wear gloves when handling — all plant parts toxic.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Foxglove in Other Locations
Frequently Asked Questions
When should I plant Foxglove in Sioux County, IA?
Sioux County is in Zone 5a with an average last frost of May 1. Plan your Foxglove planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sioux County, IA?
Sioux County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 3.
When should I plant Foxglove in Sioux County County, ?
In Sioux County County, , plant Foxglove after the last frost (around May 1) and before the first frost (around October 3). Best results when soil holds above 50°F.
What growing zone is Sioux County County, for Foxglove?
Sioux County County sits in USDA Zone 5a. Foxglove grows reliably in zones 3a through 9a, so it's a good fit here.
Can Foxglove grow in Sioux County County's climate?
Yes — Foxglove grows well in Sioux County County's temperate climate. Sioux County County averages a 155-day frost-free season, with last frost around May 1 and first frost around October 3.
Your Sioux County Garden Planner — Free
A 22-page printable planner built for Sioux County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.