When to Plant Daikon in Multnomah County, OR
Your May planting checklist for Multnomah County, Oregon
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Multnomah County, Oregon.
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Harvest daikon as they ripen
Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.
A few tasks this May that'll pay off in June
- First harvests: daikon
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.
Multnomah County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.
At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Daikon to ensure they mature before fall.
Multnomah County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.3
Drainage
Well Drained
Plant Planting Risk Windows
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 Multnomah County
How your county's soil matches Daikon's growing requirements.
Soil pH
Your soil pH (5.8–6.3) is within Daikon's preferred range (5.8–7.0).
Soil Texture
The silt loam soil in Multnomah County is excellent for Daikon — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Daikon.
Organic Matter
Organic matter is excellent (4.5%) — Daikon will thrive.
How to Plant Daikon
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Daikon
Sow every 5.7 weeks. Last sowing by Aug 18 to harvest before frost.
For a dedicated fall crop, sow by Sep 01.
Plant Water Budget
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 | — | 5.8" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | — | 3.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.3" | 2" | 💧 Light watering |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jul | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Aug | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | — | 6" | 0" | ❄️ Dormant |
| Dec | — | 4.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Multnomah 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 Planting Timeline — Multnomah County, OR
Daikon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | March 24 | Mar 24 – Apr 14 |
| Harvest | May 19 | May 19 – Jun 16 |
| Fall Sowing | September 1 | Sep 1 – Sep 15 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Direct Sow |
| April | Direct Sow |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | Fall Sowing |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.8–7 · Your soil: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
196 days in Multnomah County
Growing Tips for Daikon in Multnomah County
Direct sow Daikon outdoors after April 14 in Multnomah 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
Check more plant combinations with our Companion Planting Checker →
Daikon in Other Locations
Frequently Asked Questions
When should I plant Daikon in Multnomah County, OR?
Multnomah County is in Zone 9a with an average last frost of April 14. Plan your Daikon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Multnomah County, OR?
Multnomah County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 27.
Your Multnomah County Garden Planner — Free
A 24-page printable planner built for Multnomah County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.