When to Plant Cosmos in Lavaca County, TX
Cosmos (Cosmos bipinnatus) is an airy, feathery-foliaged cottage garden annual from Mexico that thrives on neglect. It produces delicate daisy-like blooms in shades of pink, white, and magenta from midsummer until frost. Cosmos is a prolific self-sower — once established in a garden it often returns year after year without replanting. Excellent habitat plant for beneficial insects.
Lavaca County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is December 1, giving you a growing season of approximately 278 days.
At an elevation of 254 feet, Lavaca County receives approximately 60.4 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Cosmos during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cosmos root diseases.
Lavaca County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.8
Drainage
Well Drained
Monthly Watering Guide for Cosmos
Cosmos needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Cosmos Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Mar | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Apr | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.6" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 10.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 5.1" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Nov | 4.3" | 2.4" | 1.9" | 💧 Light watering |
| Dec | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
Water needs are for active growing months only (Feb–Dec in Lavaca County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Cosmos Planting Timeline — Lavaca County, TX
Cosmos Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 29 | Jan 29 – Feb 12 |
| Transplant Outdoors | January 29 | Jan 29 – Feb 12 |
| Direct Sow | January 29 | Jan 29 – Feb 19 |
| Bloom | April 9 | Apr 9 – Sep 24 |
Plant 0.3" deep · 12" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors Direct Sow |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | — |
| April | Bloom |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–8 · Your soil: N/A
🗺️ USDA Zone
Zone 9a
📆 Growing Season
278 days in Lavaca County
Growing Tips for Lavaca County
Direct-sow after last frost; cosmos germinates readily at 65-80°F in 7-10 days. Avoid rich soil — excess fertility produces lush foliage at the expense of blooms. Cosmos tolerates poor, dry soil exceptionally well. Pinch seedlings at 8 inches to encourage branching. Self-sows freely; allow some seed heads to mature and drop for a no-fuss perennial effect in warm climates.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Cosmos in Other Locations
Frequently Asked Questions
When should I plant Cosmos in Lavaca County, TX?
Lavaca County is in Zone 9a with an average last frost of February 26. Plan your Cosmos planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lavaca County, TX?
Lavaca County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is December 1.
Your Lavaca County Garden Planner — Free
A 22-page printable planner built for Lavaca County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.