Troubleshooting
Calendula 'Radio' problems — and how to fix them
Calendula 'Radio' (Calendula officinalis 'Radio') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Powdery mildew
Grey-white coating in humid, crowded conditions or late season. Space plants, water at the base, and remove affected leaves.
Aphids
Cluster on buds and shoot tips. Hose off or use insecticidal soap; calendula also attracts aphid predators as a companion plant.
Stops flowering / sets seed
Seed-setting halts bloom and heat can stall it. Deadhead regularly and the cool-season display lasts far longer.
Leggy, sparse plants
Caused by shade or rich soil. Grow in full sun and pinch young plants to encourage bushy, floriferous growth.
Prevent calendula 'radio' problems before they start
Most calendula 'radio' issues are care-mismatch, not bad luck. Dial in the basics:
- Common calendula problems — the species this cultivar belongs to
- What's wrong with my plant? — the diagnosis apps compared
- Calendula 'Radio' watering schedule
- Calendula 'Radio' light requirements
- Best soil mix for calendula 'radio'
- Calendula 'Radio' temperature & humidity
- Full calendula 'radio' care guide
Looking for the species overview? Calendula — the full care guide.
Other Calendula varieties
Calendula 'Radio' problems — FAQ
Why is my calendula 'radio' powdery mildew?
Grey-white coating in humid, crowded conditions or late season. Space plants, water at the base, and remove affected leaves.
Why is my calendula 'radio' aphids?
Cluster on buds and shoot tips. Hose off or use insecticidal soap; calendula also attracts aphid predators as a companion plant.
Why is my calendula 'radio' stops flowering / sets seed?
Seed-setting halts bloom and heat can stall it. Deadhead regularly and the cool-season display lasts far longer.
Why is my calendula 'radio' leggy, sparse plants?
Caused by shade or rich soil. Grow in full sun and pinch young plants to encourage bushy, floriferous growth.