Petunias are adaptable plants that can thrive in the ground or planters. Their relatively easy care requirements and abundant flowers make Petunias a very popular choice for containers and hanging baskets. These stunners will bloom from the spring through the fall and add greenery and blooms to porches and patios.
Some varieties naturally maintain a more compact look, while trailing types add a dramatic burst of color as they overflow their containers. Growing Petunias in pots is very easy, especially if you follow some simple care tips.
Petunias are one of the most popular annual flowers grown in gardens. These pretty bloomers come in a rainbow of colors and add cheerful color to outdoor beds and containers. But did you know petunias can also be grown successfully indoors?
Typically petunias are grown as annuals and discarded after one season. But by providing the right care, petunias can be kept alive and blooming for years as indoor houseplants.
In this article, we’ll cover how to grow petunias indoors, including tips on lighting, watering, propagation, and troubleshooting Follow these guidelines, and your petunias will continue flowering season after season as gorgeous indoor plants
Choosing the Best Varieties for Indoor Growth
There are many different types of petunias available. When selecting plants for indoor growing, stick to just a couple varieties known to do well inside.
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Grandiflora – One of the most common bedding petunias, these produce large showy blooms on mounded plants. ‘Celebrity’ and ‘Ultra’ series do well indoors
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Multiflora – More compact and weather-tolerant than Grandiflora. Look for ‘Madness’ and ‘Wave’ series.
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Milliflora – Very compact with tons of small flowers. ‘Fantasy’ types work well.
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Double – Double-flowered selections like ‘Double Cascade’ are stunning indoors but slower growing.
Avoid spreading types sold as groundcovers. These aggressive growers require more space than most indoor gardens allow. Stick to compact, mounding varieties instead.
Providing Proper Lighting Conditions
Petunias need at least 5-6 hours per day of direct sun to thrive. South-facing windows are ideal for winter growing. Move plants to east or west windows in hot summer months to avoid afternoon sun.
If natural light is insufficient, supplement with grow lights. LED full spectrum bulbs placed 6-12 inches above plants for 14-16 hours daily provide the bright light petunias need.
Insufficient light leads to leggy, weak growth and fewer blooms. Note that flowering significantly declines in winter without supplemental lighting. Rotate plants frequently for even exposure.
Maintaining Ideal Temperatures
Petunias prefer warm, consistent temperatures between 60-75°F during the day and above 55°F at night. Avoid drafty locations which can shock plants.
Move petunias away from cold windowsills in winter. Place portable heaters nearby or incorporate heating mats if room temps drop too low at night.
High temperatures also impact flowering. Ideally daytime temperatures should remain below 80°F. Move plants to cooler areas and increase air circulation on hot days.
Watering Correctly to Prevent Disease
Petunias are susceptible to root rot if overwatered. Allow the top inch of soil to dry between waterings. Feel the soil or lift pots to gauge when plants need water.
When watering, thoroughly saturate the entire root zone until water drains from the bottom. Avoid frequent, light waterings which encourage disease.
Drooping leaves indicate underwatering. Repot plants in free-draining soil and discard any rotten roots if drainage is poor. Water less in winter when growth slows.
Providing Nutrient-Rich Soil
Like most flowering plants, petunias need soil rich in organic matter. Aim for a lightweight, quick-draining mix.
Premixed potting soils are fine, or make your own blend. Combine peat moss, compost, vermiculite and perlite for excellent aeration and drainage.
Fertilize every 2-4 weeks during the growing season with a balanced liquid fertilizer diluted to half-strength. Feed less in winter and discontinue in cold months.
Controlling Height with Pruning
Petunias grow rapidly when happy and can become leggy over time. Prune plants every 2-4 weeks to encourage bushiness.
Remove spent blooms and pinch or snip back leggy stems above leaf nodes. Cutting plants back halfway promotes branching and flowering.
To maximize fullness, also pinch growing tips periodically. Spread pruning tasks out over time to maintain shape without scalping plants.
Propagating to Extend Bloom Period
Take stem cuttings in summer to early fall to replace aging plants with fresh new ones. This extends overall bloom duration indoors.
Cut 4-6 inch tips from healthy stems. Remove lower leaves and place cuttings in water or damp soilless mix. Keep moist until rooted.
As existing plants decline, replace with newly rooted cuttings. You can also root vines that trail over pot edges for a cascading effect.
Troubleshooting Common Indoor Petunia Problems
Raising healthy, flowering petunias indoors does take some practice. Check for these common issues if your plants underperform:
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Leggy growth: Insufficient light, overcrowding, or inadequate pinching back. Increase light exposure, space plants, and prune more aggressively.
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Few or no flowers: Lighting is too low or temperatures too high. Supplement sun exposure and lower indoor temps.
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Yellowing leaves: Overwatering or inadequate drainage. Allow soil to dry between waterings and repot in fresh mix if needed. Discard diseased roots.
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Curled, distorted leaves: Aphid infestation. Check undersides of leaves and rinse off pests with water. Apply insecticidal soap if severe.
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White crusty deposits: Mealybugs are present. Wipe leaves with alcohol to remove the pesky bugs.
With extra care taken to get conditions just right, petunias can be grown successfully indoors for many seasons. Follow these tips, and you’ll have gorgeous flowering plants to enjoy inside long after outdoor petunias have expired.
Frequently Asked Questions About Growing Petunias Indoors
If you’re new to raising petunias as houseplants, chances are you have some questions. Here are answers to some of the most common inquiries about growing petunias indoors.
How long do petunias live as houseplants?
With proper care, most petunias live 2-3 years indoors. Take stem cuttings periodically to refresh plants and extend overall bloom time.
What size pot do petunias need indoors?
Use a 12-16 inch pot for one plant or mixed planting. Petunias grown alone can reach 18+ inches across at maturity. Give them room to spread out.
Should I deadhead indoor petunias?
Yes! Deadhead spent blooms frequently by pinching them off. This promotes continued flowering and tidiness.
How do I get petunias to rebloom?
Improve light exposure, fertilize regularly, and deadhead spent blooms to encourage repeat flowering. Take cuttings to replace aging plants.
What causes leggy petunias indoors?
Insufficient sunlight, overcrowding, and neglecting to prune leggy stems leads to stretchy, weak growth. Improve conditions and prune more often.
Do petunias need direct sunlight indoors?
At least 4-6 hours of direct sun daily is best. Supplement with grow lights if needed. Flowering declines significantly in winter without enough light.
Should I mist my indoor petunias?
Avoid misting, which increases humidity and disease risk. Water only when soil is partly dry, and always water thoroughly until it drains from the pot bottom.
Enjoy Season after Season of Gorgeous Petunias
Petunias are not just pretty annuals for outdoor gardens. They make fabulous long-blooming houseplants too.
By choosing compact varieties suited to indoor growing and providing ample light, warm temps, and well-draining soil, petunias can thrive indoors for years.
Periodic cuttings extend bloom time even further. Just be sure to prune plants often to keep them full and bushy. With a little practice, you can enjoy delightful petunia flowers inside your home long after outdoor plants have expired.
The effort is well worth it for their cheery floral display. Petunias are one of my favorite indoor plants, and I hope you’ll give growing them inside a try this year!
Planting Petunias in Pots
Petunias can be planted throughout the growing season, but it is most common to plant during the spring. You can plant Petunias as long as there is no chance of a frost, and with the right conditions and care, the plants will last into the fall. Keep in mind that Petunias planted later in the growing season will not have very established root systems and will need water more often to combat warm temperatures.
Petunias are very well suited to drier soil and warm temperatures, so containers are a natural fit since the soil dries out and heats up rather quickly. Petunia plants are not very particular regarding the pots they call home. As long as the pot has a drainage hole and enough space for the roots to spread, the plant will thrive. Generally, try to plant no more than 3 Petunias in a 12-inch pot.
Porous planters, like unglazed ceramic and terracotta, allow the soil to dry out more quickly, which is suitable for Petunias. However, you will need to water the plants more often if the soil is drying out more quickly. Non-porous planters, like glazed ceramic and plastic, are also good choices, as long as they have drainage.
Fertilizing Petunias in Pots
Feed Petunias in pots every other week using a balanced liquid fertilizer like 8-8-8 or 10-10-10. Petunias are heavy feeders, and we recommend keeping up with a regular fertilizing schedule to promote healthy growth and plentiful blooms.