Mammoth Sunflowers are...mammoth. This variety reaches over 10' tall with heads that span 12"". Super easy to grow and great for kids who want to live in their own version of Honey I Shrunk The Kids. You can even roast the seeds for a nutritious snack. Start indoors, then transplant outdoors into your garden or a container. This Mammoth Sunflower seed starting kit is packaged in a nutrient-rich, biodegradable CowPot that helps heal soil and support healthy plant growth. CowPots are 100% biodegradable, natural, sustainable, recycled and eliminate the need for plastic because it’s the bio pot you plant! Tender, young roots easily penetrate the sides and bottoms of CowPots, growing freely. This allows for air pruning and formation of root buds. Secondary root development throughout the pot grow into dense, healthy root systems recognized as critical to growing healthy plants.