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When to Plant Portulaca in Hanover, MB

Portulaca (Portulaca grandiflora), commonly called moss rose, is a succulent- stemmed annual built for hot, dry, low-fertility conditions where other flowers fail. Its silky, rose-like blooms open in full sun and close at night or on cloudy days. Excellent for slopes, rock gardens, containers, and parking-strip plantings where irrigation is limited. One of the easiest annuals for neglect- proof summer color.

Hanover, Manitoba is in USDA Zone 4b. The average last spring frost is May 8 and the first fall frost is October 2, giving you a growing season of approximately 147 days.

At an elevation of 813 feet, Hanover receives approximately 13.5 inches of rainfall annually with predominantly black chernozem soil. Summer highs average 70°F, so choose short-season varieties of Portulaca to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Portulaca successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Summer Pollinator-friendly Deer-resistant
Hanover, MB (Zone 4b) Short season
147 days
Last Spring Frost May 8
147 growing days
First Fall Frost October 2

Hanover Soil Profile

Soil Type

Black Chernozem

Soil pH

6.0-7.0

Drainage

Well Drained

Portulaca Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 2
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 2
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 29 🌸 Bloom: Jun 17 – Sep 2

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.

How to Plant Portulaca

8"
Between Plants
10"
Between Rows

Portulaca Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 150 gal / 100 sq ft

Monthly Watering Guide for Portulaca

Portulaca 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 Portulaca Needs Rainfall You Supplement Action
Jan 0.5" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 0.8" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.5" 0.7" 💧 Light watering
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 1.6" 0.6" 💧 Light watering
Aug 2.2" 1.5" 0.7" 💧 Light watering
Sep 2.2" 1.3" 0.9" 💧 Light watering
Oct 2.2" 0.9" 1.3" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Portulaca 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.

Portulaca needs ~150 GDD — county provides 367 GDD Excellent fit

Portulaca Planting Timeline — Hanover, MB

Portulaca Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 22 May 22 – Jun 12
Bloom July 10 Jul 10 – Sep 25

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4b

📆 Growing Season

147 days in Hanover

Growing Tips for Portulaca in Hanover

Hanover receives only 14" of rain annually. Portulaca needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow after last frost once soil warms to 65°F, or start indoors 4–6 weeks before last frost. Seed is tiny — surface sow and do not cover. Thin to proper spacing after germination. Thrives in poor, well-drained soil; rich or wet soil produces lush foliage but fewer blooms. No deadheading required — plants are self-cleaning. Double-flowered varieties hold blooms open longer in overcast conditions.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Portulaca in Hanover, MB?

Hanover is in Zone 4b with an average last frost of May 8. Plan your Portulaca planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hanover, MB?

Hanover, Manitoba is in USDA Hardiness Zone 4b. The average last spring frost is May 8 and first fall frost is October 2.

🌱

Your Hanover Garden Planner — Free

A 22-page printable planner built for Hanover (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Hanover, MB. Local conditions may vary. Last updated: June 2026.

Sources & credits

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