Comparison: Best Costco Organic Potting Mix (Updated | Nov 11th)
But with a few different options on the warehouse shelves, how do you know which one delivers the best value and performance? We’ve dug into the details, tested the mixes, and compared ingredients, texture, and plant results so you don’t have to. Let’s find out which organic potting mix truly earns its spot in your garden—and your cart.
- Best for peat-free blend: Back to the Roots 100% Organic Potting Mix (Value 12 Quart) | Premium Blend | Made in The USA
- Best for quick-release fertilizer: Miracle-Gro Organic Outdoor Potting Mix
- Best for water balance guard: Miracle-Gro Organic Indoor Potting Mix
- Best for dual-bag value: Miracle-Gro Organic Outdoor Potting Mix
- Best for large-scale coverage: Miracle-Gro Organic Outdoor Potting Mix
- Best for root-boosting mix: Back to the Roots 100% Organic Indoor Potting Mix (Value 12 Quart) | Promotes Healthy Houseplant Growth| Made in The USA
- Best for all-purpose organic: Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening
- Best for twin indoor packs: Miracle-Gro Organic Indoor Potting Mix
Product Comparison: Best Costco Organic Potting Mix
Back to the Roots 100% Organic Potting Mix (Value 12 Quart) | Premium Blend | Made in The USA
- 100% Organic and Peat-Free: Our potting mix is 100% organic and peat-free—made from upcycled plant matter and wood fines from across the U.S. No imported peat, just better soil with a lighter carbon footprint.
- All-Purpose: Our premium potting mix is versatile and well-suited for herbs, veggies, fruits, and flowers. It caters to all your gardening needs, and is proudly made in the USA.
- Better Moisture Control and pH Balance: Our premium soil blend incorporates yucca extract for moisture control and dolomitic limestone for pH balancing.
- 100% Satisfaction Guarantee: Not satisfied? Let us know. Our support team will get you growing with a replacement or refund—no questions asked.
- GROWONEGIVEONE — Share a photo of your growing garden and we’ll donate a Kids Grow Kit and STEM elementary school curriculum to a classroom of your choice.
Miracle-Gro Organic Outdoor Potting Mix, for Outdoor Container Plants, Contains Quick-Release Natural Fertilizer, OMRI Listed, 16 qt.
- Miracle-Gro Organic Outdoor Potting Mix contains a quick-release natural fertilizer and also feeds plants for up to 2 months
- This potting mix is made with responsibly sourced peat (one hundred percent of peat sourced from certified producers)
- Use this organic potting mix with all types of outdoor container plants, including flowers, vegetables, herbs, annuals, and perennials
- To plant in pots, fill the container partially full with potting mix, place the plant in the pot after loosening the root ball, cover with more mix and water thoroughly
- One 16 qt. bag of Miracle-Gro Organic Outdoor Potting Mix fills one 12-inch container (amounts may vary based on the size of the root ball)
Miracle-Gro Organic Indoor Potting Mix, Protects Against Over and Under Watering, for Indoor Container Plants, Houseplants and Starter Plants, OMRI Listed, 16 qt.
- Miracle-Gro Organic Indoor Potting Mix protects indoor plants against over and under watering
- This organic container mix is made with responsibly sourced sphagnum peat moss (one hundred percent of peat sourced from certified producers), coir, and quick-start natural fertilizer
- Use this potting medium with all types of indoor container plants, including houseplants and herbs; also great for seed starting
- To plant seeds, fill container with potting mix, follow seed package planting directions, and water; To use with transplants, partially fill container, place plant after loosening the root ball, cover with more mix pressing lightly, and water
- One 16 qt. bag of Miracle-Gro Organic Indoor Potting Mix fills one 12-inch container (amounts may vary based on the size of the root ball)
Miracle-Gro Organic Outdoor Potting Mix, for Outdoor Container Plants, Contains Quick-Release Natural Fertilizer, OMRI Listed, 16 qt., 2-Pack
- Miracle-Gro Organic Outdoor Potting Mix contains a quick-release natural fertilizer and also feeds plants for up to 2 months
- This potting mix is made with responsibly sourced peat (one hundred percent of peat sourced from certified producers)
- Use this organic potting mix with all types of outdoor container plants, including flowers, vegetables, herbs, annuals, and perennials
- To plant in pots, fill the container partially full with potting mix, place the plant in the pot after loosening the root ball, cover with more mix and water thoroughly
- This bundle includes two 16 qt. bags of Miracle-Gro Organic Outdoor Potting Mix; each fills one 12-inch container (amounts may vary based on the size of the root ball)
Miracle-Gro Organic Outdoor Potting Mix, for Outdoor Container Plants, Contains Quick-Release Natural Fertilizer, OMRI Listed, 25 qt.
- Miracle-Gro Organic Outdoor Potting Mix contains a quick-release natural fertilizer and also feeds plants for up to 2 months
- This potting mix is made with responsibly sourced peat (one hundred percent of peat sourced from certified producers)
- Use this organic potting mix with all types of outdoor container plants, including flowers, vegetables, herbs, annuals, and perennials
- To plant in pots, fill the container partially full with potting mix, place the plant in the pot after loosening the root ball, cover with more mix and water thoroughly
- One 25 qt. bag of Miracle-Gro Organic Outdoor Potting Mix fills three 10-inch containers (amount may vary based on the size of the root ball)
Back to the Roots 100% Organic Indoor Potting Mix (Value 12 Quart) | Promotes Healthy Houseplant Growth| Made in The USA
- FORMULATED FOR INDOOR USE: Our Potting Mix contains organic yucca extract that aids in retaining moisture in the soil whichs keeps your indoor plants happy and healthy
- ROOT-BOOSTING MYCORRHIZAE: This beneficial soil component provides your plants with a natural, organic way to boost their root development and nutrient uptake
- ORGANIC AND PEAT-FREE: Our indoor potting mix helps reduce greenhouse emissions and environmental impact, making it a responsible choice for conscious consumers
- BALANCING DOLOMITIC LIMESTONE: Balances the alkalinity and acidity levels of the soil, which ensures that your plants receive the necessary nutrients from the potting mix to grow healthy and strong
- SAFE FOR PETS AND PEOPLE: Made without bark or compost, this potting mix is less prone to indoor gnats and pests, making it a worry-free option for your indoor gardening needs
Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening, 2 Cubic Foot bag. Pack of1
- FOR USE ON: Not just an indoor potting soil, this can also be used as a potting soil for outdoor plants and is a great soil mix for vegetables, herbs & all other container plants & flowers.
- CONTAINS: This organic soil for plants & vegetables is a rich blend of sphagnum peat moss, humus & perlite enriched with earthworm castings, alfalfa meal, kelp meal & feather meal
- MYCO-TONE: A proprietary blend of endo & ecto mycorrhizae.
- WHEN TO USE: Any time planting containers, whether starting a new plant or transplanting into a larger container. Plants require regular re-potting and fresh planting soil for optimum growth
- ORGANIC GARDENING: Contains a rich blend of only the finest natural ingredients. No synthetic plant foods or chemicals are used.
Miracle-Gro Organic Indoor Potting Mix, Protects Against Over and Under Watering, for Indoor Container Plants, Houseplants and Starter Plants, OMRI Listed, 16 qt., 2-Pack
- Miracle-Gro Organic Indoor Potting Mix protects indoor plants against over and under watering
- This organic container mix is made with responsibly sourced sphagnum peat moss (one hundred percent of peat sourced from certified producers), coir, and quick-start natural fertilizer
- Use this potting medium with all types of indoor container plants, including houseplants and herbs; also great for seed starting
- To plant seeds, fill container with potting mix, follow seed package planting directions, and water; To use with transplants, partially fill container, place plant after loosening the root ball, cover with more mix pressing lightly, and water
- This bundle includes two 16 qt. bags of Miracle-Gro Organic Indoor Potting Mix; each bag fills one 12-inch container (amounts may vary based on the size of the root ball)
Miracle-Gro Organic Indoor Potting Mix, Protects Against Over and Under Watering, for Indoor Container Plants, Houseplants and Starter Plants, OMRI Listed, 8 qt., 2-Pack
- Miracle-Gro Organic Indoor Potting Mix protects indoor plants against over and under watering
- This organic container mix is made with responsibly sourced sphagnum peat moss (one hundred percent of peat sourced from certified producers), coir, and quick-start natural fertilizer
- Use this potting medium with all types of indoor container plants, including houseplants and herbs; also great for seed starting
- To plant seeds, fill container with potting mix, follow seed package planting directions, and water; To use with transplants, partially fill container, place plant after loosening the root ball, cover with more mix pressing lightly, and water
- This bundle includes two 8 qt. bags of Miracle-Gro Organic Indoor Potting Mix; each bag fills two 8-inch containers (amounts may vary based on the size of the root ball)
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Buying Guide
FAQs
What should I look for when choosing an organic potting mix for indoor plants?
Focus on mixes that offer moisture regulation, balanced pH, and pet‑safe ingredients. Ingredients like yucca extract, dolomitic limestone, and mycorrhizal fungi help retain water and support root health. Avoid blends with heavy peat or added synthetic fertilizers if you prefer a peat‑free, low‑odor option.
How does Back to the Roots Indoor Mix compare to Miracle‑Gro Indoor Mix?
Back to the Roots uses a peat‑free formula with upcycled plant material and yucca extract for moisture control, while Miracle‑Gro relies on peat moss, coir, and a quick‑release natural fertilizer. Both provide balanced pH, but Back to the Roots includes mycorrhizal fungi for root boosting and is marketed as pet‑safe. Miracle‑Gro may give a slightly faster nutrient boost due to its fertilizer component.
Which mix offers the best value for large outdoor container gardens?
Miracle‑Gro’s 25 qt. Outdoor Mix fills three 10‑inch containers, providing a lower cost per volume than the 12 qt. or 16 qt. bags. The larger bag reduces packaging waste and is ideal for extensive planting. If you need multiple containers, the bundled 2‑bag 16 qt. packs also deliver savings.
Are there any environmental advantages to choosing a peat‑free mix?
Peat‑free mixes, like Back to the Roots, use upcycled plant matter and wood fines, reducing carbon emissions associated with peat extraction. They also lower the risk of peat‑related soil compaction. Choosing a peat‑free product supports sustainable gardening practices.
Do any of these mixes contain added fertilizers, and how long do they last?
Miracle‑Gro’s Organic Outdoor and Indoor mixes include a quick‑release natural fertilizer that feeds plants for up to two months. Back to the Roots relies on its organic blend without added fertilizer, encouraging slower, steady nutrient release. If you prefer less frequent feeding, the fertilizer‑free option may be better.
Which potting mix is best for seed starting and transplanting?
Both Back to the Roots Indoor Mix and Miracle‑Gro Indoor Mix are suitable for seed starting, offering fine texture and good water retention. Back to the Roots adds mycorrhizal fungi, which can enhance seedling vigor. Miracle‑Gro’s quick‑start fertilizer can give seedlings an early nutrient boost.
How important is mycorrhizal fungi in a potting mix?
Mycorrhizal fungi form a symbiotic relationship with plant roots, improving nutrient uptake and drought tolerance. Back to the Roots Indoor Mix includes these fungi, which can lead to healthier, faster‑growing plants. While not essential, they add a valuable performance edge for serious gardeners.
What are the price‑to‑performance considerations for the Espoma Organic Potting Soil?
Espoma offers a rich blend of peat, humus, perlite, and organic amendments like kelp and feather meal, providing comprehensive nutrition. It’s versatile for indoor and outdoor use but typically costs more per quart than the basic Back to the Roots mixes. If you need a single, all‑purpose organic soil and value nutrient diversity, Espoma may justify the higher price.