Products We Love: Canna’s Terra Professional Plus soil. It’s seed-starting time for outdoor gardeners and Canna’s Terra Professional Plus is our favorite soil to start seeds in. It’s a blend of peat moss, coco coir and composted tree bark, with a slight nutrient charge that’s mild enough for seedlings but strong enough for more established plants too (no fertilizing necessary for 2-3 weeks). The tree bark gives the soil natural aeration without the addition of perlite (so no white spots in your garden). Available in 1.77 cubic foot bags.