When to Plant Sweet Alyssum in Carson County, TX
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Sweet Alyssum (Lobularia maritima) is a low-growing cool-season annual prized for its honey-scented clusters of tiny white, pink, or purple flowers. A workhorse border plant, it tolerates light frost, self-seeds readily, and attracts beneficial insects throughout its bloom season. In warm climates it often re-blooms in fall after summer heat fades.
Carson County, Texas is in USDA Zone 7a. The average last spring frost is April 14 and the first fall frost is October 25, giving you a growing season of approximately 194 days.
At an elevation of 2,585 feet, Carson County receives approximately 45.2 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 99°F, so Sweet Alyssum may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sweet Alyssum will need more frequent watering and organic matter to retain nutrients.
Carson County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.9-8.8
Drainage
Well Drained
Sweet Alyssum 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 Carson County
How your county's soil matches Sweet Alyssum's growing requirements.
Soil pH
Your soil pH (7.9–8.8) is more alkaline than Sweet Alyssum prefers (6.0–7.5). Add sulfur or peat moss to lower pH.
Soil Texture
Sandy soil in Carson County warms quickly in spring but drains fast. Sweet Alyssum will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Sweet Alyssum.
Organic Matter
Organic matter is low (1.0%). Add 2-3 inches of compost before planting Sweet Alyssum.
How to Plant Sweet Alyssum
Fall planting: Sow 6 weeks before your first frost date for a fall harvest.
Succession Planting Sweet Alyssum
Sow every 5.1 weeks. Last sowing by Aug 26 to harvest before frost.
For a dedicated fall crop, sow by Sep 13.
Sweet Alyssum Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Sweet Alyssum
Sweet Alyssum 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 | Sweet Alyssum Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.5" | 0" | ❄️ Dormant |
| Feb | — | 2.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| May | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Jun | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Jul | 2.2" | 7.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Carson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sweet Alyssum 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.
Sweet Alyssum Planting Timeline — Carson County, TX
Sweet Alyssum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 3 | Mar 3 – Mar 17 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | March 17 | Mar 17 – Apr 7 |
| Bloom | May 26 | May 26 – Aug 18 |
| Fall Sowing | September 13 | Sep 13 – Sep 27 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| 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
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 7a
📆 Growing Season
194 days in Carson County
Growing Tips for Sweet Alyssum in Carson County
Direct sow Sweet Alyssum outdoors after April 14 in Carson County when soil has warmed and frost danger has passed.
Sandy soil in Carson County dries quickly — mulch Sweet Alyssum with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 99°F in Carson County, provide afternoon shade for Sweet Alyssum and water deeply in the morning.
Your generous 194.0-day season in Carson County allows multiple plantings of Sweet Alyssum. Sow every 22.0 days for continuous harvest.
Common pests for Sweet Alyssum in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Surface-sow seeds — they need light to germinate. Direct-sow as soon as soil can be worked in spring; in zones 7+ also sow in fall. Thin to 6 inches apart. Shear back hard in midsummer when heat causes dormancy — plants recover and re-bloom when cool weather returns. Self-seeds prolifically; allow a few plants to set seed for a perpetual colony.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Sweet Alyssum in Other Locations
Frequently Asked Questions
When should I plant Sweet Alyssum in Carson County, TX?
Carson County is in Zone 7a with an average last frost of April 14. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Carson County, TX?
Carson County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 14 and first fall frost is October 25.
Your Carson County Garden Planner — Free
A 22-page printable planner built for Carson County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.