Calendula - Garden Guide
Calendula Care At A Glance
- Annual flower or herb with bright orange, yellow or white blooms.
- Prefers well-drained, organically rich soil in full to part sun.
- Tolerant of cold weather makes it a good option for early spring and fall.
- Also known as Pot Marigold or English Marigold.
- Edible flower petals used for salad spice or historically as medicinal plants.
Planting Instructions
Follow similar steps as you would for other annual flowers:
- Start seeds indoors 6-8 weeks before the last average frost date.
- Sow seeds into pre-moistened seed starting mix in trays or individual plantable pots or use Jiffy-7 plant starters. NOTE: Seeds must be started at lower temperatures than most annual flowering plants. Warmer temperatures lead to weaker finished plants.
- Optimal bottom heat range is 55° to 65°F. Germination in 7-14 days typically.
- Cover 1/4 to 1/2-inch with moistened mix and keep seeds well covered since light prevents germination.
- Keep medium moist but not soggy.
- After germination, place seedlings into bright light, but maintain a cool temperature.
- Transplant seedlings after two to four sets of true leaves develop.
- Harden off seedlings for 5-10 days before planting outside.
- Seeds can be sown directly outdoors a few weeks before the last frost while temperatures are cool, following these same basic guidelines above.
Care & Maintenance
- Plant seedlings 6-12 inches apart in well-drained soil, with full to part sun.
- Calendula can be grown equally well in containers as in-ground using the same methods.
- Individual plant size varies by variety, with full-sized and dwarf selections available.
- Regular deadheading of spent blooms helps keep plants blooming and maintains desirable bushy plants.
Watering
Maintain consistent regular watering, using a 1-inch per week rule.
Fertilizing
Utilize fertilizers with a formula lower in nitrogen but higher in phosphorus and potassium.
- Fertilize with a complete, water-soluble food once every two weeks, such as ALGOPlus Flowering Plant 4-6-7.
- Another option is to broadcast a 3-5-3 granulated, slow-release fertilizer into beds or pots 3-4 weeks before setting out transplants. A rate of 3-5 lbs. per 100 sq. ft. can be used for beds or follow product label instructions for application rates for potted plants. NOTE: Fertilizers with high nitrogen produce excessive vegetative growth while inhibiting flowers.
Troubleshooting
Powdery Mildew
- Calendula plants are susceptible to powdery mildew.
- Maintain proper plant spacing and provide good air circulation to prevent disease.
- Preventative fungicide applications with sulfur or bio-fungicides such as Bonide® Revitalize® work well.
Seed Germination Issues
- Lack of germination can be due to improper soil temperature.
- Germination can be halted or inhibited by light. Ensure seeds are covered adequately but not too deep.
- Lack of consistent moisturecauses low to no germ.
- Stretching seedlings is due to lack of adequate sunlight and temp. Too high, or a combination of both.
Lack of Flowering
- Inadequate sunlight. Provide plants with 4 or more hours of sunlight.
- Excess nitrogen or nutrient imbalance. See fertilizing above.
- High temperatures. If plants are deadheaded or kept pinched back and otherwise healthy, they can resume flowering when temperatures drop again.
Insect Issues
- Aphids - Manage their occurrence with insecticidal soap (Safer® Insect Killing Soap)
- Snails or Slugs chew holes in leaves. Manage with homemade, in-ground cider vinegar or beer traps, or with applications of Diatomaceous Earth around plants or by application of snail/slug baits (Sluggo® Plus)
- Cabbage looper can also chew foliage. Manage by hand picking when found or with Bt spray applications such as Thuricide®. Other insecticides with low-impact active ingredients, such as Spinosad or Bonide® Pyrethrin, can also be used effectively.
