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How to Grow Petunia Plant Indoors

Updated: July 2, 2023

Petunias are beautiful, versatile flowering plants that are often used to add color and life to outdoor gardens and landscapes. However, did you know that petunias can also be grown indoors? Growing petunia plants indoors allows you to enjoy their vibrant blooms all year round, regardless of the weather outside. In this article, we will explore the steps to successfully grow petunias indoors and provide some useful tips for maintaining their health and beauty.

Choosing the Right Petunia Variety

When it comes to growing petunias indoors, selecting the right variety is crucial. There are hundreds of different petunia cultivars available, each with its own unique characteristics and growth habits. Some popular varieties for indoor gardening include:

  1. Grandiflora Petunias: These petunias produce large, showy flowers in a wide range of colors. They are known for their trumpet-like shape and are perfect for adding a splash of color to any indoor space.

  2. Multiflora Petunias: Multiflora petunias have smaller flowers compared to grandiflora varieties but make up for it with their prolific blooming nature. They are more tolerant of adverse conditions, making them a great choice for beginners.

  3. Surfinia Petunias: Surfinia petunias are trailing varieties that work well in hanging baskets or as cascading plants on shelves or windowsills. They produce an abundance of flowers and can create a stunning visual display.

  4. Calibrachoa (Million Bells): While not true petunias, calibrachoa plants closely resemble their petunia cousins. They offer vibrant colors and are excellent choices for small containers or mixed arrangements.

When selecting a petunia variety for indoor growing, consider factors such as space availability, lighting conditions, and personal preferences regarding flower size and color.

Providing the Right Growing Conditions

To ensure successful indoor petunia growth, it is essential to create an environment that mimics their natural outdoor habitat as closely as possible. Here are some key factors to consider:


Petunias thrive in bright, direct sunlight. Place your indoor petunia plants near a south-facing window where they can receive at least 6-8 hours of sunlight each day. If natural light is limited, you can supplement it with fluorescent grow lights placed 6-12 inches above the plants. Avoid placing petunias too close to windows during cold winter months, as they may suffer from drafts.

Temperature and Humidity

Petunias prefer moderately warm temperatures ranging between 65-75°F (18-24°C). Avoid exposing them to extreme temperature fluctuations or drafts, as these can damage the plants. Maintain a relative humidity level of around 50% to prevent the foliage from becoming too dry or too damp.

Soil and Potting

Use a well-draining potting mix specifically formulated for container gardening. Petunias require good soil aeration to prevent root rot and promote healthy growth. Ensure that your chosen pot has drainage holes to allow excess water to escape, preventing waterlogged soil conditions.

Planting and Care Tips

Now that you have selected the right petunia variety and set up the optimal growing conditions, here are some planting and care tips to help you successfully grow petunias indoors:

  1. Seeding or Transplanting: You can start petunias from seeds indoors about 10-12 weeks before the last expected frost date in your area. Alternatively, purchase young petunia plants from a nursery or garden center and transplant them into pots filled with moist potting mix.

  2. Watering: Petunias require regular watering to keep the soil consistently moist but not waterlogged. Check the moisture level by inserting your finger into the soil up to the first knuckle. If it feels dry, water the plants thoroughly until water drains from the bottom of the pot.

  3. Fertilizing: Feed your indoor petunias every 2-3 weeks with a balanced water-soluble fertilizer diluted to half strength. This will provide them with essential nutrients for healthy growth and abundant blooming.

  4. Pinching and Pruning: To encourage bushier growth and more flowers, pinch back the tips of young petunia plants when they reach about 4-6 inches in height. Additionally, remove any spent flowers or dead foliage regularly to promote continuous blooming.

  5. Support and Training: Depending on the petunia variety you choose, some may require support or training to prevent trailing stems from becoming tangled or damaged. Use small stakes or trellises to guide their growth if necessary.

  6. Pest and Disease Control: Monitor your indoor petunias for common pests such as aphids, whiteflies, and spider mites. Treat any infestations promptly using organic insecticidal soap or neem oil. Ensure good air circulation around the plants to prevent fungal diseases like powdery mildew.

Enjoying the Blooms

With proper care and attention, your indoor petunias will reward you with a profusion of colorful blooms throughout the year. Take some time to admire their beauty and fragrance, and don’t forget to share their vibrant presence with friends and family.

Growing petunias indoors is a rewarding experience that allows you to enjoy these stunning flowers even when outdoor gardening is not possible. Follow these guidelines, experiment with different varieties, and soon you’ll have a thriving indoor garden filled with vibrant petunias that brighten up any space!