From our perspective as plants, the single most important decision for a full hanging basket is the genetic selection of the petunia varieties. Not all petunias are created equal for this specific purpose. We, the spreading and trailing types, are your best choice. Look for labels that say "Wave," "Surfinia," "Supertunia," or "Cascadia." Our growth habit is naturally vigorous and horizontal; we are bred to rapidly colonize the space around us, spilling over the edges and weaving through the basket to create a dense, floral canopy. Planting a more upright, mounded variety would lead to a leggy and sparse appearance, as those cousins focus their energy skyward rather than outward.
Our roots are the foundation of our health and your display's fullness. We require a growing medium that provides excellent aeration, moisture retention, and a steady supply of food. A standard garden soil is too dense and will compact in the basket, suffocating our roots and stunting our growth. Instead, please use a high-quality, lightweight potting mix, ideally one that includes a slow-release fertilizer. This gives us a consistent supply of essential nutrients like nitrogen for leafy growth and phosphorus for strong root development from the very beginning. A crowded root system is a stressed root system, so ensure the basket is large enough—at least 12-14 inches in diameter—to accommodate our expansive root networks.
How you place us in the basket is critical. Do not simply plant one petunia in the center. To achieve immediate fullness and ensure we grow into a balanced sphere of color, you must plant through the sides of the basket as well as the top. For a standard 12-inch basket, we recommend using at least three to five individual plants. Gently thread the root balls of some plants through the liner's side holes, angling them slightly outward. Then, plant the remaining specimens in the top, spacing them evenly around the center. This technique allows us to immediately begin growing in all directions, filling the basket's volume efficiently and reducing competition for light at the crown, which prevents a bald spot on top.
Our initial burst of growth is just the beginning. To maintain a full look throughout the season, we need consistent care that meets our physiological needs. We are heavy feeders and drinkers. The limited soil volume in a basket dries out quickly and is quickly depleted of nutrients. A regular watering schedule is non-negotiable; water us thoroughly when the top inch of soil feels dry. Furthermore, supplement the initial slow-release fertilizer with a weekly application of a water-soluble fertilizer high in phosphorus (the middle number on the fertilizer package). This encourages continuous blooming. Most importantly, you must regularly "deadhead" us. This means pinching off the spent, wilted flowers. This prevents us from directing energy into seed production and instead redirects it back into creating new branches and a profusion of new blooms, ensuring the basket remains thick and floriferous for months.
