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When to plant Microgreens in Saint Augustine, FL

The best window to plant Microgreens in Saint Augustine, is January 19–February 9, when soil warms to 50°F. Last frost typically hits February 9; first frost December 2. A second sowing from October 7 to October 21 extends the harvest into fall.

When to Plant Microgreens in Saint Augustine, FL

St. Johns County, Florida Zone 9b June

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Your St. Johns County, Florida garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost February 9
Avg. first frost December 2
Soil temp (4") 86°F
Watering Low
Pest pressure High
Daylight 13.9 hrs

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Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Saint Augustine, Florida is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 2, giving you a growing season of approximately 296 days.

At an elevation of 57 feet, St. Johns County receives approximately 51.1 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Microgreens may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Microgreens will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Microgreens root diseases.

Saint Augustine, FL (Zone 9b) Year-round
296 days
Last Spring Frost February 9
296 growing days
First Fall Frost December 2

Saint Augustine Soil Profile

Soil Type

Sand

Soil pH

4.9-6.1

Drainage

Well Drained

Microgreens Planting Risk Windows

Early Start (70% safe) ✓ Fits season (272 days to spare)
Start indoors: Dec 28 Transplant: Jan 25 🍅 Harvest: Feb 1 – Mar 1
Recommended (50%) ✓ Fits season (261 days to spare)
Start indoors: Jan 12 Transplant: Feb 9 🍅 Harvest: Feb 16 – Mar 16
Safe Start (90%) ✓ Fits season (252 days to spare)
Start indoors: Feb 11 Transplant: Mar 11 🍅 Harvest: Mar 18 – Apr 15

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 Saint Augustine

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

Soil pH

Your soil pH (4.9–6.1) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in St. Johns County warms quickly in spring but drains fast. Microgreens will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.5%). Add 2-3 inches of compost before planting Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

58
successive plantings in your 296-day season

Sow every 0.7 weeks. Last sowing by Nov 11 to harvest before frost.

For a dedicated fall crop, sow by Oct 07.

Microgreens Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 880 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 4.3" 2.4" 1.9" 💧 Light watering
Mar 4.3" 2.8" 1.5" 💧 Light watering
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 3.5" 0.8" 💧 Light watering
Jun 4.3" 7" 0" ✅ Rainfall sufficient
Jul 4.3" 7.1" 0" ✅ Rainfall sufficient
Aug 4.3" 7.6" 0" ✅ Rainfall sufficient
Sep 4.3" 6.9" 0" ✅ Rainfall sufficient
Oct 4.3" 4.3" 0" ✅ Rainfall sufficient
Nov 4.3" 2.1" 2.2" 🚿 Regular watering
Dec 4.3" 2.3" 2" 💧 Light watering

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

Microgreens 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.

Microgreens needs ~340 GDD — county provides 7,202 GDD Excellent fit

Microgreens Planting Timeline — Saint Augustine, FL

Microgreens Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors February 9 Feb 9 – Feb 23
Direct Sow January 19 Jan 19 – Feb 9
Harvest February 16 Feb 16 – Mar 16
Fall Sowing October 7 Oct 7 – Oct 21

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

296 days in St. Johns County

Growing Tips for Microgreens in Saint Augustine

Direct sow Microgreens outdoors after February 09 in St. Johns County when soil has warmed and frost danger has passed.

Sandy soil in St. Johns County dries quickly — mulch Microgreens with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 99°F in St. Johns County, provide afternoon shade for Microgreens and water deeply in the morning.

Your generous 297.0-day season in St. Johns County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

When should I plant Microgreens in Saint Augustine, FL?

In Saint Augustine, FL, plant Microgreens after the last frost (around February 9) and before the first frost (around December 2). Best results when soil holds above 50°F.

What growing zone is Saint Augustine, FL for Microgreens?

Saint Augustine sits in USDA Zone 9b. Microgreens grows reliably in zones 1a through 13b, so it's a good fit here.

Can Microgreens grow in Saint Augustine's climate?

Yes — Microgreens grows well in Saint Augustine's temperate climate. Saint Augustine averages a 297-day frost-free season, with last frost around February 9 and first frost around December 2.

🌱

Your St. Johns County Garden Planner — Free

A 22-page printable planner built for St. Johns County (Zone 9b). 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 St. Johns County, FL. Local conditions may vary. Last updated: June 2026.