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When to Plant Daikon in Brown County, SD

Brown County, South Dakota Zone 4a May

Your May game plan for Brown County, South Dakota

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

Avg. last frost May 8
Avg. first frost October 4
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Plant daikon from seed, right in the garden

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June prep starts now
  • First harvests: daikon

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Daikon is a large, mild Japanese radish that can grow over a foot long. It is excellent for pickling, stir-fries, and as a soil-breaking cover crop.

Brown County, South Dakota is in USDA Zone 4a. The average last spring frost is May 8 and the first fall frost is October 4, giving you a growing season of approximately 149 days.

At an elevation of 536 feet, Brown County receives approximately 34.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Daikon to ensure they mature before fall.

Brown County, SD (Zone 4a) Short season
149 days
Last Spring Frost May 8
149 growing days
First Fall Frost October 4

Brown County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Transplant: Apr 30 🍅 Harvest: Jun 25 – Jul 23
Recommended (50%) ✓ Fits season (65 days to spare)
Transplant: May 8 🍅 Harvest: Jul 3 – Jul 31
Safe Start (90%) ✓ Fits season (66 days to spare)
Transplant: May 18 🍅 Harvest: Jul 13 – Aug 10

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 Brown County

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

Soil pH

Your soil pH (6.3–7.6) overlaps with Daikon's range (5.8–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Daikon

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Daikon

3
successive plantings in your 149-day season

Sow every 5.7 weeks. Last sowing by Jul 26 to harvest before frost.

For a dedicated fall crop, sow by Jul 12.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 29 gal / 100 sq ft

Monthly Watering Guide for Daikon

Daikon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Daikon Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 5.1" 0" ✅ Rainfall sufficient
Jun 4.3" 5.7" 0" ✅ Rainfall sufficient
Jul 4.3" 4" 0.3" 💧 Light watering
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.5" 0.8" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Daikon 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.

Daikon needs ~780 GDD — county provides 1,937 GDD Excellent fit

Daikon Planting Timeline — Brown County, SD

Daikon Planting Calendar

Activity When Date Range
Direct Sow May 1 May 1 – May 22
Harvest June 26 Jun 26 – Jul 24
Fall Sowing July 12 Jul 12 – Jul 26

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.8–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

149 days in Brown County

Growing Tips for Daikon in Brown County

Direct sow Daikon outdoors after May 08 in Brown County when soil has warmed and frost danger has passed.

Common pests for Daikon 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 late summer for fall harvest. Loosen soil deeply before planting. Thin seedlings to 6 inches apart. Harvest before hard freeze as exposed shoulders may crack.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Daikon in Brown County, SD?

Brown County is in Zone 4a with an average last frost of May 8. Plan your Daikon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brown County, SD?

Brown County, South Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 8 and first fall frost is October 4.

🌱

Your Brown County Garden Planner — Free

A 24-page printable planner built for Brown County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Brown 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.