When to plant Calendula in Riverview, FL
Riverview sits in USDA Zone 10a. Plant Calendula between November 16 (after last frost on January 25) and December 7. A second sowing from September 13 to September 27 extends the harvest into fall.
When to Plant Calendula in Riverview, FL
Your July gardening checklist
Your Hillsborough County, Florida garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.
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Plan the fall garden
Make a planting map for August. Tomatoes, peppers, brassicas, lettuce, root crops all go in over the next 8 weeks. Soil amendments and irrigation prep happen now.
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Keep heat-survivor crops productive
Daily harvest of okra and southern peas keeps plants producing. Let pods over-mature and the plant stops setting new fruit.
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Watch for hurricane prep season
August-October is hurricane season. Stake young trees, secure rain barrels, and plan how to protect tender transplants from high winds.
Calendula (Calendula officinalis) is a cheerful, edible-flowered cool-season annual valued by herbalists, chefs, and gardeners alike. Its golden-orange petals are used in salves, teas, and as a saffron substitute. Hardy enough to tolerate light frosts, it blooms prolifically in spring and fall, taking a pause during the hottest weeks of summer.
Riverview, Florida is in USDA Zone 10a. The average last spring frost is January 25 and the first fall frost is December 20, giving you a growing season of approximately 329 days.
At an elevation of 63 feet, Hillsborough County receives approximately 54.4 inches of rainfall annually with predominantly sand soil. Summer highs average 98°F, so Calendula may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Calendula will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Calendula root diseases.
Riverview Soil Profile
Soil Type
Sand
Soil pH
4.9-5.9
Drainage
Well Drained
Calendula Planting Risk Windows
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 Riverview
How your county's soil matches Calendula's growing requirements.
Soil pH
Your soil pH (4.9–5.9) is more acidic than Calendula prefers (5.5–7.0). Add garden lime to raise pH.
Soil Texture
Sandy soil in Hillsborough County warms quickly in spring but drains fast. Calendula will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Drainage is adequate for Calendula.
Organic Matter
Organic matter is low (1.5%). Add 2-3 inches of compost before planting Calendula.
How to Plant Calendula
Fall planting: Sow 14 weeks before your first frost date for a fall harvest.
Succession Planting Calendula
Sow every 5.7 weeks. Last sowing by Oct 11 to harvest before frost.
For a dedicated fall crop, sow by Sep 13.
Calendula Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Calendula
Calendula 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 | Calendula Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Feb | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Mar | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| May | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 7.7" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2" | 0.2" | 💧 Light watering |
| Dec | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Jan–Dec in Hillsborough County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Calendula 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.
Calendula Planting Timeline — Riverview, FL
Calendula Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | December 14 | Dec 14 – Dec 28 |
| Direct Sow | November 16 | Nov 16 – Dec 7 |
| Bloom | January 25 | Jan 25 – May 3 |
| Fall Sowing | September 13 | Sep 13 – Sep 27 |
Plant 0.3" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Bloom |
| February | Bloom |
| March | Bloom |
| April | Bloom |
| May | Bloom |
| June | — |
| July | — |
| August | — |
| September | Fall Sowing |
| October | — |
| November | Direct Sow |
| December | Transplant Outdoors Direct Sow |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 10a
📆 Growing Season
329 days in Hillsborough County
Growing Tips for Calendula in Riverview
Direct sow Calendula outdoors after January 25 in Hillsborough County when soil has warmed and frost danger has passed.
Sandy soil in Hillsborough County dries quickly — mulch Calendula with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 98°F in Hillsborough County, provide afternoon shade for Calendula and water deeply in the morning.
Common pests for Calendula in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct-sow in early spring as soon as soil can be worked — seeds germinate in cool soil (50-65°F). In zones 7+, also sow in fall for winter/spring bloom. Deadhead consistently to extend bloom. Plants self-seed readily; save a few spent heads and allow them to drop. Harvest petals when flowers are fully open for best flavor and medicinal value.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Calendula in Other Locations
When should I plant Calendula in Riverview, FL?
In Riverview, FL, plant Calendula after the last frost (around January 25) and before the first frost (around December 20). Best results when soil holds above 50°F.
What growing zone is Riverview, FL for Calendula?
Riverview sits in USDA Zone 10a. Calendula grows reliably in zones 2a through 11b, so it's a good fit here.
Can Calendula grow in Riverview's climate?
Yes — Calendula grows well in Riverview's temperate climate. Riverview averages a 330-day frost-free season, with last frost around January 25 and first frost around December 20.
Your Hillsborough County Garden Planner — Free
A 22-page printable planner built for Hillsborough County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.