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When to Plant Bok Choy in Grant County, SD

Grant County, South Dakota Zone 4b May

Your May game plan for Grant County, South Dakota

A quick May briefing for Grant County, South Dakota gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 2
Avg. first frost October 3
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Set out bok choy seedlings

    Frost risk is low now in Grant County, South Dakota. If you've been covering beds overnight, you can stop.

June will be here before you know it — start on
  • Starting indoors: bok choy
  • First harvests: bok choy

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Bok choy is a Chinese cabbage variety with crisp white stalks and dark green leaves. It is a fast-growing cool-season crop ideal for stir-fries and soups.

Grant County, South Dakota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 3, giving you a growing season of approximately 154 days.

At an elevation of 965 feet, Grant County receives approximately 30.6 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Bok Choy to ensure they mature before fall.

Grant County, SD (Zone 4b) Moderate season
154 days
Last Spring Frost May 2
154 growing days
First Fall Frost October 3

Grant County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jun 8 – Jul 13
Recommended (50%) ✓ Fits season (77 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Jun 13 – Jul 18
Safe Start (90%) ✓ Fits season (76 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jun 26 – Jul 31

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 Grant County

How your county's soil matches Bok Choy's growing requirements.

Soil pH

Your soil pH (6.4–7.4) is within Bok Choy's preferred range (6.0–7.5).

Soil Texture

The loam soil in Grant County is excellent for Bok Choy — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Bok Choy will thrive.

How to Plant Bok Choy

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Bok Choy

4
successive plantings in your 154-day season

Sow every 4.6 weeks. Last sowing by Aug 04 to harvest before frost.

For a dedicated fall crop, sow by Jul 11.

Plant Water Budget

Plant needs
0.7″/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 Bok Choy

Bok Choy needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Bok Choy Needs Rainfall You Supplement Action
Jan 0.7" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 3" 4.4" 0" ✅ Rainfall sufficient
Jun 3" 4.7" 0" ✅ Rainfall sufficient
Jul 3" 4.4" 0" ✅ Rainfall sufficient
Aug 3" 3.3" 0" ✅ Rainfall sufficient
Sep 3" 2.8" 0.2" 💧 Light watering
Oct 3" 1.8" 1.2" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Bok Choy 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.

Bok Choy needs ~650 GDD — county provides 2,002 GDD Excellent fit

Bok Choy Planting Timeline — Grant County, SD

Bok Choy Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest June 13 Jun 13 – Jul 18
Fall Sowing July 11 Jul 11 – Jul 25

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

154 days in Grant County

Growing Tips for Bok Choy in Grant County

Direct sow Bok Choy outdoors after May 02 in Grant County when soil has warmed and frost danger has passed.

Your generous 154.0-day season in Grant County allows multiple plantings of Bok Choy. Sow every 20.0 days for continuous harvest.

Common pests for Bok Choy in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall for best results. Keep soil consistently moist. Harvest whole heads or cut outer leaves for a cut-and-come-again approach.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Bok Choy in Grant County, SD?

Grant County is in Zone 4b with an average last frost of May 2. Plan your Bok Choy planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, SD?

Grant County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 3.

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Your Grant County Garden Planner — Free

A 24-page printable planner built for Grant 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 Grant 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.