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When to Plant Angelica in Ada County, ID

Ada County, Idaho Zone 6b April

Ada County, Idaho gardeners: here's your April plan

Your garden in Ada County, Idaho is working on a schedule, even when you're not. Here's where you should be this April.

Avg. last frost April 23
Avg. first frost October 16
Soil temp (4") 38°F
Watering High
Pest pressure Low
Daylight 13.2 hrs
  1. Get angelica in the ground

    Your last frost (April 23) has passed. These warm-season crops can handle outdoor soil now.

  2. Direct-sow angelica

    Your soil is 38°F — warm enough for these to germinate without babying.

May will be here before you know it — start on
  • Starting indoors: angelica

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Angelica is a dramatic biennial herb that can reach 6 feet tall with large compound leaves and globe-shaped flower clusters. All parts are edible with a sweet, celery-like flavor.

Ada County, Idaho is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 16, giving you a growing season of approximately 176 days.

At an elevation of 4,372 feet, Ada County receives approximately 19.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Angelica during the growing season. With low rainfall, drip irrigation is essential for growing Angelica successfully. Mulch heavily to conserve soil moisture.

Ada County, ID (Zone 6b) Moderate season
176 days
Last Spring Frost April 23
176 growing days
First Fall Frost October 16
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Ada County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Start indoors: Mar 11 Transplant: Apr 8
Recommended (50%) ✓ Fits season
Start indoors: Mar 19 Transplant: Apr 16
Safe Start (90%) ✓ Fits season
Start indoors: Apr 8 Transplant: May 6

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 Ada County

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

Soil pH

Your soil pH (6.4–7.7) is more alkaline than Angelica prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Angelica.

How to Plant Angelica

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.5″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,931 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Angelica

Angelica needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Angelica Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 6.5" 2" 4.5" 🚿 Regular watering
May 6.5" 2.4" 4.1" 🚿 Regular watering
Jun 6.5" 1.4" 5.1" 🚿 Regular watering
Jul 6.5" 1.8" 4.7" 🚿 Regular watering
Aug 6.5" 2.4" 4.1" 🚿 Regular watering
Sep 6.5" 1.5" 5" 🚿 Regular watering
Oct 6.5" 1.8" 4.7" 🚿 Regular watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Angelica 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.

Angelica needs ~9,581 GDD — county provides 3,080 GDD May not mature

Angelica Planting Timeline — Ada County, ID

Angelica Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors April 16 Apr 16 – Apr 30
Direct Sow April 9 Apr 9 – Apr 30
Fall Sowing August 7 Aug 7 – Aug 21

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

176 days in Ada County

Growing Tips for Angelica in Ada County

Direct sow Angelica outdoors after April 23 in Ada County when soil has warmed and frost danger has passed.

Your 176.0-day growing season in Ada County is tight for Angelica (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Angelica in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

Ada County receives only 20" of rain annually. Angelica needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Sow fresh seeds in fall for spring germination. Provide rich, moist soil and partial shade. Harvest stems in the second year before flowering for candying or flavoring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Angelica in Ada County, ID?

Ada County is in Zone 6b with an average last frost of April 23. Plan your Angelica planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ada County, ID?

Ada County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 16.

🌱

Your Ada County Garden Planner — Free

A 24-page printable planner built for Ada County (Zone 6b). 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 Ada County, ID. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.