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When to Plant Sweet Alyssum in Colfax County, NE

Colfax County, Nebraska Zone 5b June

June in Colfax County, Nebraska — your action list

We've pulled the most time-sensitive tasks for Colfax County, Nebraska this June and put them front and centre. Tackle them in order.

Avg. last frost April 22
Avg. first frost October 11
Soil temp (4") 68°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Indoor seed-starting week for sweet alyssum

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Collect sweet alyssum at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

Before July arrives, get these ready
  • First harvests: sweet alyssum

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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.

Colfax County, Nebraska is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.

At an elevation of 525 feet, Colfax County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Alyssum to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Fragrant
Colfax County, NE (Zone 5b) Moderate season
172 days
Last Spring Frost April 22
172 growing days
First Fall Frost October 11
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Colfax County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Sweet Alyssum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Start indoors: Feb 27 Transplant: Apr 17 🌸 Bloom: May 29 – Aug 7
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 4 Transplant: Apr 22 🌸 Bloom: Jun 3 – Aug 12
Safe Start (90%) ✓ Fits season (57 days to spare)
Start indoors: Mar 20 Transplant: May 8 🌸 Bloom: Jun 19 – Aug 28

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 Colfax County

How your county's soil matches Sweet Alyssum's growing requirements.

Soil pH

Your soil pH (6.4–7.7) overlaps with Sweet Alyssum's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Colfax County is excellent for Sweet Alyssum — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Sweet Alyssum.

Organic Matter

Organic matter is excellent (4.0%) — Sweet Alyssum will thrive.

How to Plant Sweet Alyssum

6"
Between Plants
8"
Between Rows

Succession Planting Sweet Alyssum

4
successive plantings in your 172-day season

Sow every 5.1 weeks. Last sowing by Aug 12 to harvest before frost.

Sweet Alyssum Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 73 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 2.6" 0" ✅ Rainfall sufficient
May 2.2" 3.6" 0" ✅ Rainfall sufficient
Jun 2.2" 3.8" 0" ✅ Rainfall sufficient
Jul 2.2" 3.2" 0" ✅ Rainfall sufficient
Aug 2.2" 2.8" 0" ✅ Rainfall sufficient
Sep 2.2" 2.4" 0" ✅ Rainfall sufficient
Oct 2.2" 1.7" 0.5" 💧 Light watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Colfax 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 needs ~682 GDD — county provides 2,236 GDD Excellent fit

Sweet Alyssum Planting Timeline — Colfax County, NE

Sweet Alyssum Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 8 Apr 8 – Apr 29
Bloom June 3 Jun 3 – Aug 12

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors
June Bloom
July Bloom
August Bloom
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

172 days in Colfax County

Growing Tips for Sweet Alyssum in Colfax County

Direct sow Sweet Alyssum outdoors after April 22 in Colfax County when soil has warmed and frost danger has passed.

Your generous 172.0-day season in Colfax 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 →

Frequently Asked Questions

When should I plant Sweet Alyssum in Colfax County, NE?

Colfax County is in Zone 5b with an average last frost of April 22. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colfax County, NE?

Colfax County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 11.

🌱

Your Colfax County Garden Planner — Free

A 22-page printable planner built for Colfax 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Colfax County, NE. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.