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When to Plant Persimmon in Jefferson County, ID

Jefferson County, Idaho Zone 5a May

May in the garden — Jefferson County, Idaho

May is a pivotal month for Jefferson County, Idaho gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 22
Avg. first frost September 21
Soil temp (4") 43°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
Looking ahead to June
  • Transplants going out: persimmon

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Persimmons are ornamental trees producing sweet, honey-flavored fruits in fall. American persimmons are astringent until fully ripe while Asian types can be eaten firm.

Jefferson County, Idaho is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 21, giving you a growing season of approximately 122 days.

At an elevation of 5,094 feet, Jefferson County receives approximately 18 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Persimmon during the growing season. With low rainfall, drip irrigation is essential for growing Persimmon successfully. Mulch heavily to conserve soil moisture.

Jefferson County, ID (Zone 5a) Short season
122 days
Last Spring Frost May 22
122 growing days
First Fall Frost September 21
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Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 30
Recommended (50%) ✓ Fits season
Transplant: Jun 12
Safe Start (90%) ✓ Fits season
Transplant: Jul 8

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 Jefferson County

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

Soil pH

Your soil pH (6.3–7.8) overlaps with Persimmon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Persimmon.

How to Plant Persimmon

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 496 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Persimmon

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

Month Persimmon Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.4" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 1.9" 2.4" 🚿 Regular watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.4" 2.9" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.6" 2.7" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Persimmon 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.

Persimmon needs ~27,831 GDD — county provides 1,860 GDD May not mature

Persimmon Planting Timeline — Jefferson County, ID

Persimmon Planting Calendar

Activity When Date Range
Transplant Outdoors June 12 Jun 12 – Jun 26

· 120" apart · Rows 144" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

1095–2555 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

122 days in Jefferson County

Growing Tips for Persimmon in Jefferson County

Direct sow Persimmon outdoors after May 22 in Jefferson County when soil has warmed and frost danger has passed.

Your 122.0-day growing season in Jefferson County is tight for Persimmon (1095.0-2555.0 days to maturity). Start indoors and choose early-maturing varieties.

Jefferson County receives only 18" of rain annually. Persimmon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Choose self-fertile varieties or plant male and female trees. American types must be fully soft-ripe before eating. Asian varieties may be eaten when firm. Minimal pruning needed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Persimmon in Jefferson County, ID?

Jefferson County is in Zone 5a with an average last frost of May 22. Plan your Persimmon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, ID?

Jefferson County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 21.

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Your Jefferson County Garden Planner — Free

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

Sources & credits

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