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When to Plant Lemon Thyme in Fall River County, SD

Fall River County, South Dakota Zone 5a May

Top priorities for Fall River County, South Dakota gardeners in May

We've pulled the most time-sensitive tasks for Fall River County, South Dakota this May and put them front and centre. Tackle them in order.

Avg. last frost May 14
Avg. first frost October 1
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Move lemon thyme into the garden

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

Fall River County, South Dakota is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is October 1, giving you a growing season of approximately 140 days.

At an elevation of 1,056 feet, Fall River County receives approximately 25.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Lemon Thyme to ensure they mature before fall.

Fall River County, SD (Zone 5a) Short season
140 days
Last Spring Frost May 14
140 growing days
First Fall Frost October 1
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Fall River County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 18 🍅 Harvest: Jul 27 – Sep 28
Recommended (50%) ✓ Fits season (0 days to spare)
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 2 🍅 Harvest: Aug 11 – Oct 13

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 Fall River County

How your county's soil matches Lemon Thyme's growing requirements.

Soil pH

Your soil pH (6.5–7.2) is within Lemon Thyme's preferred range (6.0–8.0).

Soil Texture

The loam soil in Fall River County is excellent for Lemon Thyme — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Lemon Thyme.

How to Plant Lemon Thyme

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Lemon Thyme

2
successive plantings in your 140-day season

Sow every 8 weeks. Last sowing by Jul 03 to harvest before frost.

Plant 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 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Lemon Thyme

Lemon Thyme 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 Lemon Thyme Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3" 0" ❄️ Dormant
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.9" 0" ✅ Rainfall sufficient
Sep 2.2" 2.3" 0" ✅ Rainfall sufficient
Oct 2.2" 2.2" 0" ✅ Rainfall sufficient
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Fall River County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Lemon Thyme 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.

Lemon Thyme needs ~1,040 GDD — county provides 1,820 GDD Excellent fit

Lemon Thyme Planting Timeline — Fall River County, SD

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors May 21 May 21 – Jun 4
Harvest July 30 Jul 30 – Oct 1

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July Harvest
August Harvest
September Harvest
October Harvest
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

140 days in Fall River County

Growing Tips for Lemon Thyme in Fall River County

Direct sow Lemon Thyme outdoors after May 14 in Fall River County when soil has warmed and frost danger has passed.

General growing tips

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Thyme in Fall River County, SD?

Fall River County is in Zone 5a with an average last frost of May 14. Plan your Lemon Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fall River County, SD?

Fall River County, South Dakota is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is October 1.

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Your Fall River County Garden Planner — Free

A 24-page printable planner built for Fall River 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 Fall River County, SD. Local conditions may vary. Last updated: May 2026.

Sources & credits

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