How To Plant Flowers In Large Planters

Large planters can bring a porch, patio or driveway to colorful life when you fill them to overflowing with flowering annuals. Start with a planter that’s at least 14 inches across to create a (somewhat) mobile flower garden. This large container features bloomers in bright colors: ‘Tiger Eye’ gloriosa daisy (Rudbeckia), ‘Summer Jewel Red’ Savia coccinea, Profusion Double Fire zinnia and ‘Callie Purple’ calibrachoa.

Keep big container gardens light enough to move by filling the bottom third with lightweight plastics. Upside down flower pots and an empty lidded juice bottle neatly fill space in the bottom of the pot and won’t rot during the course of many growing seasons. Using plastics in the bottom of pots also saves on soil—saving you money. Plastics promote healthy plants by providing an air pocket for plant roots, which helps to prevent waterlogged soil, even during the wettest seasons. Where to find possible space fillers for large planters? Raid your recycling bin, choosing rigid plastics over softer, milk jug-types.

Fill container gardens with a commercial planting mix developed for use in pots. This type of potting soil typically contains high levels of organic matter, such as coir (coconut fiber, which helps retain water) or shredded fir bark, along with materials like perlite to increase air pockets near plant roots. Start with a quality potting mix for best results. Fill pots two-thirds full with soil. Add slow-release fertilizer now, mixing it into soil. Use a product with low numbers similar to 4-4-4.

Blend water storing crystals into soil prior to planting. Sometimes called water retention polymers, these crystals absorb water, transforming into a gelatinous material. As soil dries, the gel also dries, releasing water into dry soil. Water storing crystals help reduce the amount of time you spend watering by releasing stored water to thirsty plant roots.