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When to plant Hyacinths in Brown County, IL

Brown County gardeners should plant Hyacinths between mid-spring and late spring in spring. With Brown County's Zone 6a climate (last frost April 17), Hyacinths needs 14–28 days to mature — plant by September 18 for a full harvest. A second sowing from September 4 to September 18 extends the harvest into fall.

When to Plant Hyacinths in Brown County, IL

Brown County, Illinois Zone 6a July

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Avg. last frost April 17
Avg. first frost October 16
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 14.6 hrs

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Hyacinths (Hyacinthus orientalis) fill the spring garden with an almost overwhelming fragrance — a single cluster of blooms can perfume an entire yard. Dense, upright spikes of waxy florets in shades of purple, pink, blue, white, and red emerge in mid-spring, bridging the gap between the first crocus and the tulip peak. Though bulbs bloom most spectacularly in their first year, established plantings continue to produce graceful, less-dense flower spikes for several years. Deer and rabbits avoid them due to toxic alkaloids.

Brown County, Illinois is in USDA Zone 6a. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 868 feet, Brown County receives approximately 36.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Hyacinths during the growing season.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Brown County, IL (Zone 6a) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Brown County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Hyacinths Planting Risk Windows

Early Start (70% safe) ✓ Fits season (175 days to spare)
Transplant: Apr 12 🌸 Bloom: Mar 29 – Apr 19
Recommended (50%) ✓ Fits season (175 days to spare)
Transplant: Apr 17 🌸 Bloom: Apr 3 – Apr 24
Safe Start (90%) ✓ Fits season (175 days to spare)
Transplant: Apr 30 🌸 Bloom: Apr 16 – May 7

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 Hyacinths's growing requirements.

Soil pH

Your soil pH (6.3–6.8) is within Hyacinths's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — Hyacinths will thrive.

How to Plant Hyacinths

6"
Planting Depth
6"
Between Plants
8"
Between Rows

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Hyacinths

16
successive plantings in your 182-day season

Sow every 1.6 weeks. Last sowing by Sep 18 to harvest before frost.

For a dedicated fall crop, sow by Sep 04.

Hyacinths Water Budget

Plant needs
0.5″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Hyacinths

Hyacinths needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Hyacinths Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4.2" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 4.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Hyacinths 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.

Hyacinths needs ~304 GDD — county provides 2,639 GDD Excellent fit

Hyacinths Planting Timeline — Brown County, IL

Hyacinths Planting Calendar

Activity When Date Range
Bloom August 21 Aug 21 – Sep 11
Fall Sowing September 4 Sep 4 – Sep 18

Plant 6" deep · 6" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July
August Bloom
September Fall Sowing Bloom
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

14–28 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

182 days in Brown County

Growing Tips for Hyacinths in Brown County

Direct sow Hyacinths outdoors after April 17 in Brown County when soil has warmed and frost danger has passed.

Your generous 182.0-day season in Brown County allows multiple plantings of Hyacinths. Sow every 7.0 days for continuous harvest.

General growing tips

Plant bulbs 6 inches deep and 6 inches apart in fall, when soil drops below 60°F. Wear gloves when handling — bulb sap causes contact dermatitis in some people. After bloom, deadhead the spent spike but leave the strap-like foliage until it yellows naturally. For naturalizing, plant at 6–8 inch spacings and allow clumps to mature undisturbed. In zones 7b–9b, treat bulbs as annuals or use pre-chilled stock; performance after year 1 declines in warm-winter zones. For forcing indoors, chill bulbs 10–12 weeks then bring into warmth.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyacinths in Brown County, IL?

Brown County is in Zone 6a with an average last frost of April 17. Plan your Hyacinths planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brown County, IL?

Brown County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 17 and first fall frost is October 16.

When should I plant Hyacinths in Brown County, IL?

In Brown County, IL, plant Hyacinths after the last frost (around April 17) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Brown County, IL for Hyacinths?

Brown County sits in USDA Zone 6a. Hyacinths grows reliably in zones 3a through 9b, so it's a good fit here.

Can Hyacinths grow in Brown County's climate?

Yes — Hyacinths grows well in Brown County's temperate climate. Brown County averages a 182-day frost-free season, with last frost around April 17 and first frost around October 16.

🌱

Your Brown County Garden Planner — Free

A 22-page printable planner built for Brown County (Zone 6a). 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 Brown County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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