Zinnia care guide

Zinnia

Also known as: Common zinnia, Youth-and-age

Pets and children

We haven't been able to confirm how this plant affects pets or small children. If any is eaten, consult a veterinarian or a doctor.

How often to water Zinnia

Spring–Summer (Mar–Sep)
Every 3 days
Water the base thoroughly once the topsoil is dry, as a guide; wetting the leaves and flowers invites disease.
Autumn (Oct–Nov)
Every 4 days
It keeps flowering in fall, but with slower drying wait a day or two after the soil dries, as a rough guide.
Winter (Dec–Feb)
Every 7 days
Generally an annual killed by frost; a plant that survives into winter gets sparing water a few days after the soil dries.

Light and placement for Zinnia

Full sun and good airflow outdoors is the guide; it takes heat well, but humidity brings powdery mildew and leaf spots, so a spot under the eaves suits long rainy spells.

Overwintering Zinnia

Overwintering guide: 5°C (41°F) or above

Cold-tender and usually treated as an annual that ends before frost; save seed and sow again around May the next year, as a guide.

Fertilizing and repotting Zinnia

Fertilizer

Mix in slow-release fertilizer at planting and give liquid feed about every one to two weeks while flowering; when feed runs out the flowers shrink.

When to repot

Spring–Summer (Mar–Sep)

Common problems with Zinnia

  • Water on the leaves leads to powdery mildew turning them white.
  • In poorly draining soil the roots rot and the lower leaves die off.
  • Spent flowers left on the plant tire it and flowering drops.

Tips for growing Zinnia

  • Pinching the tip at six to eight true leaves gives more branches and more flowers.
  • Cutting back just below spent blooms keeps it flowering into fall.
  • Dwarf types suit pots and tall types suit cutting, so choose by use.

These are AI-generated general guidelines. They vary with the variety, the placement and the pot size. For effects on pets or children, consult a veterinarian or a doctor.

Keep your plant log going

Greenery is a free app that keeps your plant care going, with watering reminders and photo records. Available on iOS and Android.

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