When to plant calendula by city
Sow calendula outdoors from 2 weeks before to 2 weeks after your last frost. Here is what that means for 2027 in cities across the US, using each city’s average frost dates (NOAA 1991–2020). Pick the city with the climate most like yours, or enter your ZIP code above.
| City | Last frost | Sow outdoors |
|---|---|---|
| Seattle, WA (9a) | Mar 13 | Feb 27 – Mar 27 |
| Portland, OR (8b) | Feb 25 | Feb 11 – Mar 11 |
| Sacramento, CA (9b) | Jan 12 | Dec 29 – Jan 26 |
| Phoenix, AZ (10a) | Jan 5 | Dec 22 – Jan 19 |
| Salt Lake City, UT (7b) | Mar 31 | Mar 17 – Apr 14 |
| Denver, CO (6a) | Apr 30 | Apr 16 – May 14 |
| Dallas, TX (8b) | Mar 2 | Feb 16 – Mar 16 |
| Minneapolis, MN (5a) | Apr 23 | Apr 9 – May 7 |
| Kansas City, MO (6b) | Apr 4 | Mar 21 – Apr 18 |
| Chicago, IL (6b) | Apr 10 | Mar 27 – Apr 24 |
| Columbus, OH (6b) | Apr 20 | Apr 6 – May 4 |
| Nashville, TN (7b) | Apr 1 | Mar 18 – Apr 15 |
| Atlanta, GA (8a) | Mar 24 | Mar 10 – Apr 7 |
| Raleigh, NC (8a) | Mar 28 | Mar 14 – Apr 11 |
| Philadelphia, PA (7b) | Mar 30 | Mar 16 – Apr 13 |
| Boston, MA (7a) | Apr 4 | Mar 21 – Apr 18 |
In frost-free parts of Florida, southern California and the Gulf Coast, timing is about heat instead: grow calendula from fall through winter.
Calendula spacing
In a square-foot bed, plant 4 per square foot. In traditional rows, space plants about 10 inches apart with 12 inches between rows.
Edible petals; flowers draw hoverflies and other beneficial insects.
How to grow calendula
Calendula, or pot marigold, is an easy cool-season annual with orange and yellow daisy flowers and edible petals. It tolerates light frost and blooms best in spring and fall, often pausing in the heat of midsummer. It self-sows readily.
Sun and soil
Full sun, with light afternoon shade in hot regions. Moderately fertile, well-drained soil with a pH of about 6.0–7.0. It performs best below about 85°F.
Planting
- Direct-sow ¼ inch deep from 2 weeks before to 2 weeks after the last frost, once soil is around 50°F. Seedlings appear in 1–2 weeks.
- Thin to 10 inches apart in rows 12 inches apart.
- In mild-winter regions, a fall sowing gives flowers through winter and spring.
Care
- Pick or deadhead flowers often to keep new buds coming.
- Water about 1 inch a week; avoid soggy soil, which leads to root rot.
- Feed sparingly. If plants stall in summer heat, cut them back by about half and they will rebloom in fall.
- Mature plants survive light frosts down to the mid-20s °F.
Harvest
Pick flowers when fully open, ideally in the morning after dew dries. Use petals fresh in salads, or dry whole flowers out of direct sun until crisp and store them airtight. Plants rebloom within a couple of weeks.
Common problems
- Powdery mildew: White patches on leaves, worse in cool, humid weather. Space plants, water at the base, and remove affected leaves.
- Aphids and whiteflies: Clusters on stems and leaf undersides. Use a hard spray of water or insecticidal soap.
- Midsummer decline: Heat stops flowering. Cut plants back and keep them watered until cooler weather returns.
Varieties to try
- 'Pacific Beauty' — tall mix, more heat tolerant
- 'Resina' — high-resin flowers, grown for herbal use
- 'Touch of Red' — double flowers with red-tipped petals
Crop rotation
Calendula belong to the daisy family (Asteraceae). Few shared soil problems; fits anywhere in a rotation. Relatives that count as the same family for rotation: lettuce, red leaf lettuce, sunflower, marigold, zinnia.
Frequently asked questions
When should I plant calendula?
What grows well with calendula?
How far apart should I plant calendula?
How long do calendula take to grow?
Can calendula handle frost?
Sources
- Frost dates: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020.
- Hardiness zones: 2023 USDA Plant Hardiness Zone Map, USDA-ARS and PRISM Climate Group, Oregon State University.
- Planting windows and spacing: Vegetable Planting Guide (GardenNotes #720), Colorado State University Extension, and other land-grant extension guides.
- Gardening with Companion Plants (EM128E), Linda Chalker-Scott, Washington State University Extension, 2023
- Calendula in the Garden — Utah State University Extension