When to Plant Crocus in Sullivan County, TN
Sullivan County, Tennessee gardeners: here's your June plan
Your garden in Sullivan County, Tennessee is working on a schedule, even when you're not. Here's where you should be this June.
Crocuses (Crocus spp.) are the heralds of spring — small, gem-like blooms that push up through frozen ground or even snow, often weeks before any other flower. Their compact corms naturalize readily in lawns, rock gardens, and borders, creating drifts of purple, white, and yellow that expand year after year. Bees prize early crocus as one of their first nectar and pollen sources of the season. The saffron crocus (C. sativus) blooms in fall and yields the world's most expensive spice.
Sullivan County, Tennessee is in USDA Zone 7b. The average last spring frost is April 23 and the first fall frost is October 19, giving you a growing season of approximately 179 days.
At an elevation of 3,986 feet, Sullivan County receives approximately 46.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Crocus during the growing season.
Sullivan County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-7.1
Drainage
Well Drained
Crocus 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 Sullivan County
How your county's soil matches Crocus's growing requirements.
Soil pH
Your soil pH (5.4–7.1) overlaps with Crocus's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Sullivan County is excellent for Crocus — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Crocus.
How to Plant Crocus
Fall planting: Sow 5 weeks before your first frost date for a fall harvest.
Succession Planting Crocus
Sow every 1.1 weeks. Last sowing by Sep 29 to harvest before frost.
For a dedicated fall crop, sow by Sep 14.
Crocus Water Budget
Monthly Watering Guide for Crocus
Crocus 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 | Crocus Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.9" | 0" | ❄️ Dormant |
| Feb | — | 3.3" | 0" | ❄️ Dormant |
| Mar | — | 4.7" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.8" | 0" | ❄️ Dormant |
| Dec | — | 3.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Sullivan County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Crocus 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.
Crocus Planting Timeline — Sullivan County, TN
Crocus Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Bloom | August 10 | Aug 10 – Aug 31 |
| Fall Sowing | September 14 | Sep 14 – Sep 28 |
Plant 4" deep · 3" apart · Rows 4" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | — |
| August | Bloom |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
10–20 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 7b
📆 Growing Season
179 days in Sullivan County
Growing Tips for Crocus in Sullivan County
Direct sow Crocus outdoors after April 23 in Sullivan County when soil has warmed and frost danger has passed.
Your generous 179.0-day season in Sullivan County allows multiple plantings of Crocus. Sow every 5.0 days for continuous harvest.
General growing tips
Plant corms 3–4 inches deep and 2–3 inches apart in fall, when soil temperature drops below 60°F. Mass plantings (at least 25 corms per cluster) create the most visual impact. Plant in well-drained soil — corms rot in standing water. Crocus naturalize well under deciduous trees; the tree leafs out after crocus dormancy begins, so light competition is minimal. Squirrels and chipmunks dig corms — plant deeper (4 inches) or use wire mesh baskets in high-predation areas. Allow foliage to die back naturally before mowing lawns. In zones 8a–8b, plant in December with pre-chilled corms for best results.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Crocus in Other Locations
Frequently Asked Questions
When should I plant Crocus in Sullivan County, TN?
Sullivan County is in Zone 7b with an average last frost of April 23. Plan your Crocus planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sullivan County, TN?
Sullivan County, Tennessee is in USDA Hardiness Zone 7b. The average last spring frost is April 23 and first fall frost is October 19.
Your Sullivan County Garden Planner — Free
A 22-page printable planner built for Sullivan County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.