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When to Plant Tomatoes in Buffalo County, SD

Buffalo County, South Dakota Zone 4b May

This month in Buffalo County, South Dakota

Here's what deserves your attention in Buffalo County, South Dakota this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 9
Avg. first frost October 5
Soil temp (4") 53°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Move tomatoes into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Seed tomatoes outdoors

    Your soil is 53°F — warm enough for these to germinate without babying.

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Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Buffalo County, South Dakota is in USDA Zone 4b. The average last spring frost is May 9 and the first fall frost is October 5, giving you a growing season of approximately 149 days.

At an elevation of 840 feet, Buffalo County receives approximately 23.7 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Buffalo County, SD (Zone 4b) Short season
149 days
Last Spring Frost May 9
149 growing days
First Fall Frost October 5

Buffalo County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 22 🍅 Harvest: Jul 24 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Mar 7 Transplant: May 30 🍅 Harvest: Aug 1 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 10 🍅 Harvest: Aug 12 – Oct 21

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 Buffalo County

How your county's soil matches Tomatoes's growing requirements.

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Tomatoes prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Buffalo County is excellent for Tomatoes — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Tomatoes.

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Tomatoes.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

2
successive plantings in your 149-day season

Sow every 6.9 weeks. Last sowing by Jul 12 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.7″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,183 gal / 100 sq ft

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 5.2" 3.2" 2" 💧 Light watering
Jun 5.2" 4.3" 0.9" 💧 Light watering
Jul 5.2" 3.4" 1.8" 💧 Light watering
Aug 5.2" 2.6" 2.6" 🚿 Regular watering
Sep 5.2" 2.1" 3.1" 🚿 Regular watering
Oct 5.2" 1.6" 3.6" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

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

Tomatoes 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.

Tomatoes needs ~888 GDD — county provides 1,825 GDD Excellent fit

Tomatoes Planting Timeline — Buffalo County, SD

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors May 30 May 30 – Jun 13
Direct Sow May 23 May 23 – Jun 13
Harvest August 1 Aug 1 – Oct 10

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · 2-3 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

149 days in Buffalo County

Growing Tips for Tomatoes in Buffalo County

Direct sow Tomatoes outdoors after May 09 in Buffalo County when soil has warmed and frost danger has passed.

Common pests for Tomatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

Buffalo County receives only 24" of rain annually. Tomatoes needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Recommended Tomatoes Varieties for Buffalo County

Choose determinate, early-maturing varieties for your short season

Early Girl (52d) Stupice (55d) Glacier (55d) Sub Arctic Plenty (45d)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35°F, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Buffalo County, SD?

Buffalo County is in Zone 4b with an average last frost of May 9. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Buffalo County, SD?

Buffalo County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 9 and first fall frost is October 5.

🌱

Your Buffalo County Garden Planner — Free

A 24-page printable planner built for Buffalo County (Zone 4b). 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 Buffalo 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.