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When to Plant Sweet Alyssum in Boyd County, NE

Boyd County, Nebraska Zone 5a June

What to do in June

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

Avg. last frost May 3
Avg. first frost October 7
Soil temp (4") 66°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Get sweet alyssum seeds going inside

    You're about 16 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Start harvesting sweet alyssum

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Get ahead of July
  • 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.

Boyd County, Nebraska is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.

At an elevation of 667 feet, Boyd County receives approximately 28 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Sweet Alyssum to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Fragrant
Boyd County, NE (Zone 5a) Moderate season
157 days
Last Spring Frost May 3
157 growing days
First Fall Frost October 7

Boyd County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.3

Drainage

Well Drained

Sweet Alyssum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (48 days to spare)
Start indoors: Mar 8 Transplant: Apr 26 🌸 Bloom: Jun 7 – Aug 16
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 15 Transplant: May 3 🌸 Bloom: Jun 14 – Aug 23
Safe Start (90%) ✓ Fits season (41 days to spare)
Start indoors: Mar 29 Transplant: May 17 🌸 Bloom: Jun 28 – Sep 6

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 Boyd County

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

Soil pH

Your soil pH (6.4–7.3) is within Sweet Alyssum's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Sweet Alyssum.

How to Plant Sweet Alyssum

6"
Between Plants
8"
Between Rows

Succession Planting Sweet Alyssum

4
successive plantings in your 157-day season

Sow every 5.1 weeks. Last sowing by Aug 08 to harvest before frost.

Sweet Alyssum Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.1" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.4" 0" ✅ Rainfall sufficient
Aug 2.2" 3.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.4" 0" ✅ Rainfall sufficient
Oct 2.2" 2" 0.2" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Boyd 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 ~604 GDD — county provides 1,805 GDD Excellent fit

Sweet Alyssum Planting Timeline — Boyd County, NE

Sweet Alyssum Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 3 May 3 – May 17
Direct Sow April 19 Apr 19 – May 10
Bloom June 14 Jun 14 – Aug 23

· 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
July Bloom
August Bloom
September
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: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Boyd County

Growing Tips for Sweet Alyssum in Boyd County

Direct sow Sweet Alyssum outdoors after May 03 in Boyd County when soil has warmed and frost danger has passed.

Your generous 157.0-day season in Boyd 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 Boyd County, NE?

Boyd County is in Zone 5a with an average last frost of May 3. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Boyd County, NE?

Boyd County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 7.

🌱

Your Boyd County Garden Planner — Free

A 22-page printable planner built for Boyd 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.

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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 Boyd 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.