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When to Plant Salsify in Jefferson County, MO

Jefferson County, Missouri Zone 6b May

Your May game plan for Jefferson County, Missouri

Your Jefferson County, Missouri garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 10
Avg. first frost October 26
Soil temp (4") 63°F
Watering Moderate
Pest pressure Low
Daylight 14.1 hrs

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Salsify is a root vegetable with a subtle oyster-like flavor, earning it the nickname "oyster plant." It produces long, slender, cream-colored roots.

Jefferson County, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 26, giving you a growing season of approximately 199 days.

At an elevation of 839 feet, Jefferson County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Salsify during the growing season.

Jefferson County, MO (Zone 6b) Moderate season
199 days
Last Spring Frost April 10
199 growing days
First Fall Frost October 26
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Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (49 days to spare)
Transplant: Apr 4 🍅 Harvest: Jul 18 – Aug 29
Recommended (50%) ✓ Fits season (52 days to spare)
Transplant: Apr 10 🍅 Harvest: Jul 24 – Sep 4
Safe Start (90%) ✓ Fits season (51 days to spare)
Transplant: Apr 23 🍅 Harvest: Aug 6 – Sep 17

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 Salsify's growing requirements.

Soil pH

Your soil pH (5.7–7.1) overlaps with Salsify's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Salsify.

How to Plant Salsify

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

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 515 gal / 100 sq ft

Monthly Watering Guide for Salsify

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

Month Salsify Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Salsify 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.

Salsify needs ~1,754 GDD — county provides 3,034 GDD Excellent fit

Salsify Planting Timeline — Jefferson County, MO

Salsify Planting Calendar

Activity When Date Range
Direct Sow March 27 Mar 27 – Apr 17
Harvest July 10 Jul 10 – Aug 21
Fall Sowing August 17 Aug 17 – Aug 31

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

100–130 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

199 days in Jefferson County

Growing Tips for Salsify in Jefferson County

Direct sow Salsify outdoors after April 10 in Jefferson County when soil has warmed and frost danger has passed.

Common pests for Salsify in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring in deeply worked, stone-free soil. Use fresh seed only as viability drops quickly. Harvest in late fall after frost for best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Salsify in Jefferson County, MO?

Jefferson County is in Zone 6b with an average last frost of April 10. Plan your Salsify planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MO?

Jefferson County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 26.

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Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson 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 Jefferson County, MO. 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.