Quick Grow Facts

• Exact scope: Seed-raised Petunia × hybrida series plus Caliburst Petchoa (Petunia sp. × Calibrachoa sp.).
• Seed form: Pelleted in every active packet covered here. Sow one pellet per cell.
• Pretreatment: None. Do not soak or chill the seed. Mist the sown pellet thoroughly so its coating softens.
• Depth and light: Surface-sow on pre-moistened fine mix, press into contact and do not cover. Bright light supports reliable home germination.
• Temperature: Keep the mix at 22–25 °C for most series, 22–24 °C for Duo, Double Cascade, Pirouette, Frost and Ultra, and 20–25 °C for Caliburst.
• Germination: Usually 7–10 days in a well-managed home tray. Controlled breeder trays may show radicles in 3–7 days; allow up to 14 days before diagnosing failure if home temperatures fluctuate.
• Tray timing: Start about 8–10 weeks before safe planting-out weather. Petunias are too small for reliable direct sowing in an open bed.
• Transplanting: Move seedlings into individual cells or small pots at about three true leaves. Harden them for 7–10 days before planting outside.
• Light after transplanting: Full sun gives the strongest flowering—aim for at least six hours. Caliburst also accepts partial sun; extreme inland heat may justify light afternoon relief.
• Garden spacing: Series-specific, from 20–25 cm for Duo and Shake to 30–61 cm for Tidal Wave. Never apply a universal 20 × 20 cm grid.
• Flowering outcome: Home-grown plants commonly begin flowering about 10–14 weeks from sowing; doubles and cool or short-day crops may take 12–16 weeks.
• Safety: Grow these as ornamentals, not as an edible crop. Keep seed packets and pellets away from children and pets.

How to Sow Pelleted Petunia Seed

1. Prepare the tray. Fill clean cells with a fine, sterile, free-draining seedling mix. Level gently and water from below or with a fine rose before sowing.
2. Surface-sow. Place one pellet on each moist cell and press it lightly into contact. Do not bury it, add vermiculite or cover it with an opaque layer.
3. Dissolve the pellet. Mist until the coating visibly softens. During the first few days keep the surface evenly moist and humid, but never leave the cells standing in water. A hard, dry pellet can trap the seed; saturation encourages damping-off.
4. Hold the correct temperature. A clear cover helps stabilise moisture, but keep it out of scorching direct sun. Target the series temperature shown above and provide bright light.
5. Act at emergence. As soon as green seedlings appear, remove or vent the cover, increase airflow and keep the tray in strong light. Let the surface become slightly less wet between gentle waterings without allowing the tiny roots to dry.

Do not thin by pulling. Pelleted seed is intended for one seed per cell. If two seedlings emerge, snip the weaker seedling at mix level. When plants have about three true leaves, lift by a leaf rather than the stem and pot on without burying the growing point.

Transplanting and Hardening Off

Grow seedlings cool and bright after emergence—roughly 16–20 °C is suitable once they are established. Rotate trays, water in the morning and begin a dilute balanced feed after true leaves develop. Weak, stretched seedlings need more light, not deeper planting or extra nitrogen.

Harden plants for 7–10 days by gradually increasing outdoor sun and wind exposure while keeping them protected from frost, heavy rain and severe heat. Plant at the same depth as the plug into fertile, compost-enriched soil that drains freely. Use the series spacing below; it is measured from centre to centre.

Choose the Right Petunia Series

Carpet Multiflora Petunias

Carpet is a compact, well-branched multiflora series with mid-sized single blooms. Its smaller flowers and heat tolerance make it a strong bedding choice where summer weather is less gentle than large-flowered grandiflora types prefer. Surface-sow the pellets at 22–25 °C, expect home germination in about 7–10 days, and space plants 25–38 cm apart.

Shop Carpet: Carpet Blue Star, Carpet Mix and Carpet Yellow.

Daddy and Dreams Grandiflora Petunias

Daddy and Dreams are mounded, upright grandiflora series with large single flowers. The stocked packets are pelleted even though the breeder can supply these series in more than one seed form. Give them 25–36 cm spacing, root-zone watering and protection from repeated heavy rain. They suit pots and prominent bedding positions where their large blooms can be seen closely.

Shop Daddy and Dreams: Daddy Mix, Dreams Burgundy Picotee, Dreams Mix and Dreams White.

Frost Mix Grandiflora Petunia

Frost Mix is a vigorous mounded grandiflora selection, about 30–35 cm high and 35–40 cm wide. Its name describes the flower pattern, not cold hardiness: plants remain frost-tender. Sow the pellets on the surface at 22–24 °C with light and no cover over the seed. Keep the pellets fully moistened during the first few days and space finished plants 35–40 cm apart.

Shop Frost: Petunia Frost Mix.

Ultra Star Mix Grandiflora Petunia

Ultra Star Mix is a legacy compact grandiflora selection with an upright, mounded form. Expect plants around 30–35 cm high and 35–40 cm wide, so allow 35–40 cm between centres. Germinate the surface-sown pellets at 22–24 °C and protect the large patterned blooms from persistent rain.

Shop Ultra: Petunia Ultra Star Mix.

Sophistica Grandiflora Petunias

Sophistica is a mounded grandiflora series, about 25–38 cm high and 25–30 cm wide. Space plants 25–36 cm apart. Blackberry gives deep, near-black colour; Lime Bicolor can change its balance of green, yellow and pink tones as temperature and light change. That natural colour response is not a nutrient disorder.

Shop Sophistica: Sophistica Blackberry and Sophistica Lime Bicolor.

Double Cascade and Pirouette Double Grandiflora Petunias

These series carry large double grandiflora blooms on mounded upright plants about 25–38 cm high and 25–30 cm wide. The local packets are pelleted. Surface-sow at 22–24 °C and use 25–36 cm spacing. Double flowers hold more water than single flowers, so grow them in airy pots or sheltered beds, irrigate at the root and remove collapsed blooms promptly. In home conditions, allow roughly 12–16 weeks from sowing to a strong flowering display.

Shop double grandiflora: Double Cascade Mix, Pirouette Red and Pirouette Rose.

Duo Double Multiflora Petunia

Duo Mix is materially different from the double grandiflora series: it combines double flowers with a compact multiflora build. Plants finish around 25–38 cm high and 25–30 cm wide, but breeder garden spacing is a tighter 20–25 cm. Surface-sow the pellets at 22–24 °C. The smaller blooms generally clean up and recover after rough weather faster than double grandiflora flowers.

Shop Duo: Petunia Duo Mix.

Supercascade Grandiflora Petunias

The exact breeder series is Supercascade. Despite some legacy product wording, these are mounded, upright single grandiflora petunias—not a true trailing or spreading Wave series. Expect about 25–38 cm height and 25–30 cm width and space at 25–36 cm. The local packets are pelleted; surface-sow at 22–25 °C.

Shop Supercascade: Supercascade Burgundy, Supercascade Mix, Supercascade Blue, Supercascade Red and Supercascade White.

Easy Wave Spreading Petunias

Easy Wave forms broad mounds about 15–30 cm high and 76–99 cm wide. Sow the pellets on the surface at 22–25 °C and give finished plants 25–38 cm spacing; the shoots will grow together or spill over a container edge. Do not pinch routinely. Strong light, regular feeding and an even water supply are more important than forcing early branching.

Shop Easy Wave: Easy Wave Burgundy Star, Easy Wave Pink Passion, Easy Wave Red Velour and Easy Wave White.

Shock Wave Spreading Petunias

Shock Wave is a smaller-flowered spreading series, about 18–25 cm high and 51–76 cm wide. Its smaller flowers rebound rapidly after rain, making it useful for exposed baskets and beds. Surface-sow the pellets at 22–25 °C, space plants 25–38 cm apart and do not use the old 20 cm spacing. The Deep Purple product retains its existing store handle even though that handle contains an older copied name.

Shop Shock Wave: Shock Wave Deep Purple and Shock Wave Red.

Tidal Wave Spreading Petunias

Tidal Wave is the most vigorous series in this family. Plants reach roughly 41–56 cm high and 76–152 cm across. Use 30–61 cm spacing: closer planting creates a taller hedge, while wider spacing lets each plant spread. Shoots can grow upward through a low support, but this is optional. Surface-sow the pellets at 22–25 °C and provide a large soil volume, dependable water and regular feeding.

Shop Tidal Wave: Tidal Wave Red Velour and Tidal Wave Silver.

Shake Blueberry Compact Petunia

Shake Blueberry is a compact Petunia × hybrida with an upright, mounded form, about 15–20 cm high and 20–25 cm wide. Space home-garden plants 20–25 cm apart; this is a conservative width-based interpretation supported by the breeder-distributor dimensions and the local description. Surface-sow the pelleted seed at 22–25 °C and keep plants airy in humid districts.

Shop Shake: Petunia Shake Blueberry.

Caliburst Yellow Petchoa

Caliburst is not an ordinary Petunia series. It is a seed-raised Petchoa, Petunia sp. × Calibrachoa sp., with a mounded, spreading and trailing form. Plants finish about 15–25 cm high and 51–71 cm wide. Sow the pellet on the surface at 20–25 °C, keep it moist enough to dissolve and allow 25–38 cm spacing. Grow in sun or partial sun; the previous full-shade instruction is incorrect.

Shop Caliburst: Caliburst Yellow Petchoa.

Petunias in South African Climate Regions

Winter-rainfall Western Cape

Start protected trays in late summer to early autumn for cool-season colour, or in late winter for spring planting. Keep pellets and seedlings out of driving winter rain and use containers or raised beds that drain freely. Full winter and spring sun is valuable. Shelter Double Cascade, Pirouette and other grandiflora displays from repeated storms; Carpet, Duo, Shock Wave and Tidal Wave recover more readily. In dry summer wind, check containers daily.

Frost-prone interior

Sow under cover in late winter and plant out only after the last hard frost. An autumn crop needs a frost-free patio, tunnel or movable container. “Frost Mix” and breeder descriptions such as cold-durable refer to cool production performance, not frost resistance. Harden seedlings carefully because bright inland sun and dry wind can scorch soft growth.

Humid coast and KZN Midlands

Use the cooler, drier months where possible. Choose the wider end of each spacing range, give plants morning sun and moving air, and water the mix rather than the flowers. Carpet, Duo and Shock Wave are useful where rain frequently marks large blooms. Avoid densely packed double and grandiflora plants; remove storm-damaged flowers before grey mould develops.

Hot-dry or subtropical interior

Sow in late summer or autumn for the cooler flowering season. Germinate at the controlled temperatures in this guide rather than in a tray baking in direct sun. Established plants still need strong light, but light afternoon relief can extend flowering during severe heat. Use larger water-reservoir containers, free drainage and mulch only after planting; keep mulch away from the crown. Carpet and the spreading Wave series cope better than delicate double blooms, provided they never dry to wilting.

Care, Flowering and the Expected Outcome

• Soil: Use fertile, compost-enriched soil or quality potting mix with fast drainage. Petunias dislike stagnant water around the roots.
• Water: Water deeply at mix level, then allow drainage. Keep small pots evenly moist in hot or windy weather, but do not leave saucers full of water.
• Feeding: Start a dilute balanced feed after true leaves appear. Feed established container plants lightly and regularly according to the fertiliser label; pale new growth and falling flower numbers often indicate exhausted nutrition or a root problem.
• Pinching and trimming: The named modern series generally branch without routine pinching. Do not pinch Wave or Caliburst seedlings as a default. If an established plant becomes long and bare in mid-season, trim no more than about one third, feed and water it to restart growth.
• Deadheading: Remove wet, collapsed or mouldy flowers. Double and grandiflora types benefit most; spreading series need less individual deadheading but still benefit from sanitation.
• Support: None is normally required. Tidal Wave can be guided through a low support when an upright screen is wanted.

Under warm, bright home conditions, single and spreading series commonly show their first flowers about 10–14 weeks from sowing. Double types, cool crops and plants grown through short days can take 12–16 weeks. The result is a long ornamental display while temperatures remain mild to warm and frost-free; petunias decline in hard frost, prolonged waterlogging or extreme heat.

Petunia Troubleshooting

Pellets do not germinate

Likely causes: the pellet was buried, remained hard and dry, overheated under a clear cover, stayed waterlogged, received too little light or was allowed to dry after cracking. Correct the sowing depth and environment before adding more water. If the surface is already saturated, increase airflow rather than misting again.

Seedlings collapse at the mix line

This is typical of damping-off. Discard affected cells, improve airflow, water in the morning, clean trays between crops and avoid saturated mix. Do not use a garden pesticide or fungicide unless its South African label explicitly covers the crop, disease and application site.

Seedlings are tall, pale or leaning

They need stronger, closer light and slightly cooler growing conditions after emergence. Do not solve stretching with extra fertiliser. Rotate trays and transplant promptly at about three true leaves.

Plants stop flowering

Check for too much shade, a dry root ball, exhausted container feed, excessive nitrogen, cramped vigorous plants or severe heat. Confirm that a spreading series has enough soil volume. Trim only established, overgrown plants; do not repeatedly pinch young Wave plants.

Flowers rot or mark after rain

Move containers under an open-sided shelter, increase spacing and remove damaged flowers. Choose multiflora or Shock Wave types for exposed sites; large double and grandiflora blooms are naturally more weather-sensitive.

Leaves are sticky, distorted or stippled

Inspect shoot tips and leaf undersides for aphids, thrips or mites. Isolate badly affected pots, wash off light infestations and use only products registered for ornamental plants, following the label exactly. Sticky foliage alone can be normal on petunias; confirm that pests are present before treating.