Comparison: Best Wonder Soil Organic Potting Soil (Updated | Nov 11th)

Wonder Soil uses a compressed coco coir base enriched with worm castings, mycorrhizae, kelp and perlite, while Back to the Roots relies on upcycled plant matter and wood fines with yucca extract for moisture control. If you prefer a peat‑free, highly aerated mix with fast expansion, Wonder Soil is a strong choice; Back to the Roots is better for gardeners who want a fully organic, US‑made blend with a lighter carbon footprint. Consider the specific plants you’re growing and whether you value added nutrients versus a more neutral medium.

Compressed coco coir bricks expand up to seven times their size when water is added, giving you more volume for storage and reducing shipping weight. They also provide excellent water retention while maintaining good drainage and aeration, which helps prevent root rot. Additionally, the bricks are resealable, keeping the mix dry and fresh for multiple uses.

Wonder Soil’s coco coir base naturally holds water while allowing excess to drain, saving up to 50% of water compared to conventional peat mixes. Miracle‑Gro’s indoor mix combines peat, coir and a quick‑release fertilizer, offering solid moisture control but generally retains more water overall, which can be a drawback for over‑watering sensitive houseplants. Choose Wonder Soil if you want a balance of retention and aeration, especially in drier climates.

The Wonder Soil Organic Cactus & Succulent Soil is formulated with fast‑draining pumice and water‑saving polymers, making it ideal for plants that dislike soggy roots. Its compressed brick expands to a light, airy mix that mimics desert conditions. While other mixes can work, this product specifically targets the drainage needs of succulents and cacti.

Each Wonder Soil wafer expands to fill an 8‑inch pot, and 18 wafers together produce about 9 quarts of soil, giving a high volume‑to‑size ratio. The 12‑quart bricks expand to roughly 7.5 gallons, which is a larger absolute amount but requires more water to reach full size. For small‑scale projects or container gardening, wafers provide convenient, pre‑sized portions, while bricks are better for bulk applications.

Both Wonder Soil and Back to the Roots advertise pet‑safe, all‑natural formulations without harmful chemicals or synthetic fertilizers. Miracle‑Gro mixes contain quick‑release fertilizers that may be irritating if ingested by pets. If you have curious animals, opting for a peat‑free, organic blend like Wonder Soil or Back to the Roots reduces the risk of toxicity.

Mycorrhizae form symbiotic relationships with plant roots, enhancing nutrient uptake and stress tolerance, while kelp provides natural hormones that promote vigorous growth. These amendments give Wonder Soil a built‑in boost that can reduce the need for supplemental fertilizers. Competing mixes may rely on external feeding schedules, so the integrated nutrients in Wonder Soil can save time and money.

Peat extraction releases stored carbon and damages sensitive ecosystems, so peat‑free products like Wonder Soil and Back to the Roots are considered more sustainable. Choosing a peat‑free mix helps lower your garden’s carbon footprint and supports responsible sourcing. While performance is key, the environmental benefit adds meaningful value for eco‑conscious gardeners.