Petunia hanging baskets stay full all summer when you start with a trailing, vigorous variety such as Wave, Supertunia or Surfinia, plant three to five plants in a 12- to 16-inch basket of quality potting mix with slow-release fertilizer, hang it where it gets at least six hours of sun, and then do three things consistently: water until it drains every time the top inch dries (daily in summer heat), feed with a water-soluble fertilizer every week or two, and cut the plants back by about a third in midsummer when they start to look stringy. Petunias are heavy feeders and heavy drinkers, so most baskets that fizzle by July have simply run out of food or dried out a few times too often.
In this guide
Key Takeaways
- Choose spreading or trailing series (Wave, Supertunia, Surfinia and similar), not upright bedding petunias.
- Bigger baskets hold more water: 14 to 16 inches is far easier to keep moist than 10 inches.
- Use a peat- or coir-based potting mix with slow-release fertilizer; never garden soil.
- Feed weekly or every other week with a water-soluble bloom fertilizer, starting a few weeks after planting.
- Shear back by a third in midsummer to reset leggy plants; flowers return within a couple of weeks.
Best Petunia Types for Hanging Baskets
Petunias fall into several groups, and only some are bred to spill over the sides of a basket. Look for these on plant tags:
| Type | Examples | Habit | Why use it |
|---|---|---|---|
| Spreading (seed-grown) | Wave, Easy Wave, Shock Wave, Tidal Wave | Low and spreading; Tidal Wave mounds taller | Vigorous, widely available, can be grown from seed |
| Vegetative trailing | Supertunia, Surfinia, Cascadias | Trailing and mounding, often self-cleaning | Heavy flowering, many colors and patterns, minimal deadheading |
| Million Bells (calibrachoa) | Superbells, Million Bells | Fine-textured trailing | Petunia relative with small flowers; mixes well |
| Grandiflora and multiflora | Many bedding series | Upright, bushy | Better for beds and upright pots, not baskets |
Many modern vegetative petunias are labeled self-cleaning, meaning old flowers drop or are hidden by new growth, which saves a lot of deadheading. Novelty patterns such as speckled night-sky types and bicolor stars are fun but sometimes less vigorous than the standard colors; mix them with a strong grower if you want a really full basket. If you are choosing between true petunias and calibrachoa, our petunia vs calibrachoa comparison covers the differences in care.
Choosing the Basket
- Size: go as big as your hook and bracket can safely carry. A 14- to 16-inch basket holds enough mix and water to get through a hot day; a 10-inch basket may need watering twice a day by midsummer. A wet 16-inch basket is heavy, so check the hook rating.
- Material: plastic baskets hold moisture longest. Wire baskets with coir liners look classic and let you plant through the sides, but dry out quickly. Self-watering baskets with a reservoir in the base are a good answer for hot, sunny spots; see our picks for the best self-watering hanging baskets.
- Drainage: make sure there are drainage holes. Petunias rot in waterlogged mix.
Potting Mix and Planting
Use a quality peat- or coir-based potting mix designed for containers. Garden soil compacts and drains poorly in baskets. Mix in a slow-release granular fertilizer at the rate on its label before planting; it provides a steady base of nutrients for the first couple of months. Some gardeners also add a water-retaining crystal product, though a good mix and a larger basket matter more.
- Fill the basket to within about an inch of the rim with moist mix.
- Space plants evenly: three in a 12-inch basket, four or five in a 14- to 16-inch basket. Wave types spread a lot, so three may be plenty.
- Plant at the same depth they were growing in their pots.
- For a wire basket with a liner, cut a few slits in the side and tuck small plants through them for flowers all the way down.
- Water thoroughly until it drains, let it drain, then hang it.
Plant after your last frost date once nights are reliably above about 50 degrees F. Petunias tolerate a light chill but stall in cold soil.
Light and Placement
Petunias flower best with six or more hours of direct sun. Under a deep porch roof or on a north-facing wall they grow long and sparse with few flowers. In very hot southern climates, a spot with afternoon shade keeps baskets from drying out too fast and the flowers from fading. Hang baskets where you can reach them easily to water, and avoid windy corners, which dry baskets quickly and batter the flowers.
Turn the basket a quarter turn every few days if one side faces a wall, so it grows evenly. For more ideas on pairing baskets with other container plantings, our houseplants and containers hub collects our container guides.
Watering
Watering is where most baskets fail. Hanging baskets are exposed to sun and wind on every side and dry out faster than any other container.
- Check daily by pushing a finger into the mix or lifting the basket; a dry basket is noticeably lighter.
- Water when the top inch is dry, slowly, until water runs out of the bottom. In midsummer that often means daily, and sometimes twice daily for small baskets in full sun.
- If the mix shrinks from the sides and water runs straight through, take the basket down and soak it in a tub of water for 20 to 30 minutes to rewet the root ball.
- Avoid letting baskets wilt repeatedly; each severe dry-out causes flower and bud drop and sets the plant back for a week or more.
- Water in the morning so foliage dries during the day.
A drip line on a timer, or a self-watering basket, takes much of the pressure off during summer and vacations. Our general guide to hanging basket care covers watering systems in more detail.
Feeding for Nonstop Flowers
Frequent watering washes nutrients out of the mix quickly, and petunias flower so heavily that they need a regular supply. Slow-release fertilizer alone rarely carries a basket through the whole summer.
- Start feeding with a water-soluble fertilizer about two to three weeks after planting.
- Use a balanced or bloom-formula fertilizer at the label’s rate every 7 to 14 days, or a weaker solution with every watering if the label allows it.
- Yellowing leaves with green veins usually point to iron deficiency, which is common in petunias when the mix pH drifts high. A fertilizer with chelated iron, or an iron supplement, corrects it.
- Top up with slow-release granules in midsummer if you cut the basket back.
Deadheading and Midsummer Cutback
Traditional petunias set seed after flowering, which slows new blooms. Pinch off spent flowers including the small green seed pod at the base, not just the petals. Self-cleaning vegetative types need much less of this.
By July, even well-fed baskets often have long bare stems with flowers only at the tips. Cut every stem back by about a third, or cut back half the stems one week and the rest the next week for a less dramatic gap. Feed and water well afterward, and the basket fills in with fresh growth and flowers within two to three weeks. If your plants are stretching early or not flowering well, see our troubleshooting guides on leggy petunias and petunias not blooming.
Combining Petunias With Other Plants
Single-variety petunia baskets give the fullest, most uniform look. Mixed baskets add interest; use the thriller, filler, spiller idea in a smaller form. Pair petunias with plants that like the same sun and frequent watering:
- Calibrachoa and bacopa for contrasting flower size
- Sweet potato vine or licorice plant for foliage color and trailing texture
- Verbena and lantana for heat tolerance
- Trailing lobelia in cooler climates and early season
Avoid pairing petunias with shade lovers like fuchsia or begonias, which want different light and water.
A Season at a Glance
- Spring, after last frost: plant or buy baskets, mix in slow-release fertilizer, water in well. Pinch the tips of young plants once to encourage branching.
- Early summer: begin liquid feeding two to three weeks after planting; water daily as temperatures climb.
- Midsummer: cut back by a third when stems get long and bare at the center; add fresh slow-release fertilizer and keep feeding.
- Late summer: keep watering and feeding; baskets that were cut back often look their best now.
- Fall: enjoy flowers until frost, then compost the plants.
If you buy a pre-planted basket from a garden center, it has usually been grown in a greenhouse on a rich feeding program. Start your own feeding within a week or two of bringing it home, and move it into full sun gradually over a few days so the leaves do not scorch.
Pests and Problems
- Budworms: small caterpillars bore into buds, leaving holes and no flowers. Look for black droppings and check under buds; hand-pick or use a Bt-based spray labeled for caterpillars.
- Aphids: clusters on new growth; rinse off with water or use insecticidal soap.
- Sticky leaves: petunia foliage is naturally slightly sticky, but excess stickiness with sooty mold suggests aphids or whiteflies.
- Root rot: wilting despite wet mix means overwatering or poor drainage; let it dry slightly and check the drainage holes.
- Gray mold: appears on spent flowers in cool, wet weather; remove dead blooms and improve airflow.
End of Season
Petunias are grown as annuals in most of the US and decline after the first frost. Compost the plants, and either reuse the old mix as a soil amendment in beds or refresh it with new potting mix and compost next spring. Clean the basket and store it dry. You can root cuttings of favorite vegetative varieties in late summer and overwinter them indoors in a bright window, though many are patented and should not be propagated for sale.
Frequently Asked Questions
How many petunias should I plant in a hanging basket?
Three plants in a 12-inch basket and four or five in a 14- to 16-inch basket. Vigorous spreading types such as Wave can fill a basket with three.
How often should I water petunia hanging baskets?
Whenever the top inch of mix is dry, which in midsummer usually means daily, and sometimes twice a day for small baskets in full sun. Water until it drains from the bottom.
What is the best fertilizer for petunia baskets?
Slow-release granules mixed in at planting, plus a water-soluble balanced or bloom fertilizer every week or two from a few weeks after planting. Include iron if leaves yellow between the veins.
Why is my petunia basket leggy?
Usually not enough sun, not enough fertilizer, or simply midsummer age. Cut stems back by a third, feed well and the basket will refill within a few weeks.
Do I need to deadhead petunias in hanging baskets?
Traditional seed-grown petunias benefit from regular deadheading, including the seed pod. Many vegetative trailing types are self-cleaning and need little or none.