Double petunia

Growing in Pots, Balconies & Indoors

Double petunias are compact, wide-spreading bedding plants (10-30 cm / 4-12 in) with full, double blooms. They are not houseplants – they need strong sun and grow leggy and shy of flowering indoors – but in pots, window boxes and hanging baskets they are among the best of all sunny balcony and patio plants.

Quick Details

• Container Size: Any pot, window box or hanging basket with good drainage; they spread and trail, so give them room
• Indoor Suitability: Not a houseplant; a very bright, sunny sill at best – they truly belong outdoors in full sun
• Best Spot: Full sun, with a little afternoon shade in hot-summer climates
• Soil & Drainage: Light, free-draining potting mix (peat/coir with perlite); it must not stay waterlogged
• Watering in Pots: Regular – pots and baskets dry fast; keep evenly moist but not soggy

Indoors & On the Windowsill

• Houseplant limits: In low light they stretch, go pale and stop blooming – this is an outdoor plant.
• Windowsill growing: A very bright, sunny sill can hold them for a while, but a balcony or patio in full sun is far better.
• Overwintering: Usually grown as annuals and replaced each year; a favourite plant can be kept over somewhere bright and frost-free.

On a Balcony or Patio

• Light & wind: This is their ideal home – railing boxes and hanging baskets in full sun. They dry out fast in wind and heat, so check them daily and water often.
• Keep them blooming: Deadhead spent flowers and they will flower non-stop through the warm season.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: Any container with strong drainage holes; skip a standing water saucer to avoid root rot. Terracotta breathes and dries faster, while glazed or plastic pots and baskets hold moisture longer.
• Potting mix: A light, free-draining potting mix – peat or coir with perlite.
• Feeding: They are hungry plants in pots – feed regularly through the season, as nutrients leach out with frequent watering; this keeps the flowers coming.
• Renewal: Being fast annuals, they are simply replaced each year rather than repotted long-term.

Bloom & Flower Guide

Quick Details

• Bloom Season: Nearly year-round in mild climates; spring through autumn (until frost) in temperate zones
• Time to First Bloom: Fast – usually within a few weeks of planting out in warm weather
• Flower Appearance: Full, double, ruffled trumpets in red, pink, purple or white, often more than one colour on a bloom
• Edibility: Ornamental only – grown for its flowers, not for eating

Detailed Blooming Overview

Double petunias carry many-petalled, ruffled blooms that look almost like small carnations. They flower generously through the warm season, especially with regular feeding and the removal of spent blooms, and in frost-free areas they can bloom for most of the year.

Flower Characteristics

• Double to multi-petalled, ruffled trumpet flowers.
• Colours include red, pink, purple and white, often bicoloured.
• Because the flowers are so full, they set little seed and put their energy into more blooms.

Bloom Care & Thinning

• Keeping it flowering: Pinch or snip off faded, mushy blooms and any leggy stems to keep new flowers coming.
• Feeding: Such heavy bloomers appreciate regular, balanced feeding through the season.

Bloom Health & Protection

• Budworm: Tobacco budworm caterpillars chew into buds and open flowers, leaving ragged holes – a Bt (Bacillus thuringiensis) spray targets the caterpillars while sparing pollinators.
• Botrytis (grey mould): In cool, damp, crowded conditions faded blooms can rot and turn fuzzy-grey – better airflow and removing spent flowers keeps it in check.