Comparison: Best Organic Choice Potting Mix Costco (Updated | Nov 11th)
If you’re on the hunt for the best organic potting mix at Costco, you’re not alone—gardeners everywhere are turning to bulk buys for quality, value, and convenience. We’ve dug into the details, tested the textures, and compared the ingredients so you don’t have to. Let’s break down the top organic picks Costco offers and find out which one earns its spot in your garden—and your wallet.
- Best for peat-free power: Back to the Roots 100% Organic Potting Mix (Value 12 Quart) | Premium Blend | Made in The USA
- Best for long-lasting feed: Miracle-Gro Organic Outdoor Potting Mix
- Best for outdoor boost: Miracle-Gro Organic Outdoor Potting Mix
- Best for mycorrhizae magic: Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening
- Best for water balance: Miracle-Gro Organic Indoor Potting Mix
- Best for indoor moisture: Back to the Roots 100% Organic Indoor Potting Mix (Value 12 Quart) | Promotes Healthy Houseplant Growth| Made in The USA
- Best for indoor care: Miracle-Gro Organic Indoor Potting Mix
- Best for big yard mix: Miracle-Gro Organic Outdoor Potting Mix
- Best for expandable coco: WONDER SOIL Organic Potting Soil | Ready to Plant Coco Coir Fully Loaded with Nutrients | 3 LBS Bag Expands to 12 Quarts of Indoor Outdoor Soil for Gardens & Plants | Incl Worm Castings
- Best for all-natural blend: Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening
Product Comparison: Best Organic Choice Potting Mix Costco
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., 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, 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)
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)
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
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, 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)
WONDER SOIL Organic Potting Soil | Ready to Plant Coco Coir Fully Loaded with Nutrients | 3 LBS Bag Expands to 12 Quarts of Indoor Outdoor Soil for Gardens & Plants | Incl Worm Castings, Perlite
- NUTRIENT RICH & INDOOR/OUTDOOR FAST GERMINATION… Wonder Soil Premium Organic Potting Soil Mix is the only dry compressed coco coir mix with added amendments of worm castings, mycorrhizae, kelp, perlite and more! Grow your plants faster with stronger roots! Peat free, all natural, family and pet safe!
- A LITTLE DOES A LOT… your little BIG bag of compressed indoor potting soil & garden soil for outdoor plants expands to 4 TIMES THE SIZE when mixed with water; easy to carry & saves vital shed space.
- PRE-MIXED & READY TO USE ORGANIC POTTING MIX … Pre-mixed and ready to use organic potting soil and garden soil mix to help make your gardening or hobby growing a breeze. Simply transplant your desired plants into their new container and add our soil mix or pour our soil mix and plant your seeds.
- WATER RETENTION & DRAINAGE… Coco coir has excellent water retention with dependable drainage and aeration in the root zone. Save up to 50% of water, fertilizer, and seed!
- HEAVY DUTY RESEALABLE BAG… Use what you need and save the rest for later! Keeping your planting soil dry and safe!
Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening, 8qt. bag. Pack of 1
- 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.
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 moisture‑retention features like yucca extract or coir, and check for a balanced pH with ingredients such as dolomitic limestone. A peat‑free formula reduces the carbon footprint and often minimizes indoor pests. Look for added mycorrhizae or worm castings, which boost root development and nutrient uptake.
How does Back to the Roots 100% Organic Indoor Mix compare to Miracle‑Gro Indoor Mix?
Back to the Roots is peat‑free, using upcycled plant matter and wood fines, while Miracle‑Gro relies on responsibly sourced peat and includes a quick‑release natural fertilizer. Both provide moisture control, but Back to the Roots adds yucca extract and mycorrhizae for root health, whereas Miracle‑Gro emphasizes a two‑month feeding schedule. Price‑wise, Back to the Roots comes in a 12‑quart value pack, offering a smaller footprint for limited indoor spaces.
Is a peat‑based outdoor mix worth the extra cost compared to a peat‑free option?
Peat‑based mixes like Miracle‑Gro Outdoor provide excellent water retention and a proven nutrient base, which can be beneficial for larger container gardens. Peat‑free alternatives, such as Wonder Soil’s coco coir blend, offer similar drainage while being more sustainable and lighter to handle. The choice often hinges on whether you prioritize eco‑friendliness or the traditional performance of peat.
Which product gives the best value for large container gardening projects?
Miracle‑Gro Outdoor Mix in the 25‑quart bag fills three 10‑inch containers, delivering a low cost per quart for extensive planting. Espoma’s Organic Potting Soil Mix, though sold in smaller bags, includes a rich blend of peat, humus, and perlite, which may require less frequent re‑potting. For sheer volume and price efficiency, the larger Miracle‑Gro bag typically offers the best bang for your buck.
Do added mycorrhizae or worm castings make a noticeable difference in plant health?
Yes, mycorrhizae form a symbiotic relationship with plant roots, improving nutrient absorption and drought resistance. Worm castings add beneficial microbes and slow‑release nutrients, enhancing soil fertility over time. Products like Back to the Roots Indoor Mix and Espoma Potting Soil explicitly list these amendments, giving them an edge for growers seeking vigorous growth.
How important is the source of peat in an organic potting mix?
Certified peat sources ensure sustainable harvesting practices, reducing environmental impact. Both Miracle‑Gro mixes highlight that 100% of their peat comes from certified producers, which can reassure eco‑conscious shoppers. If peat‑free is a priority, alternatives like Back to the Roots and Wonder Soil eliminate peat entirely while still delivering strong performance.
What are the key differences between indoor and outdoor organic mixes?
Indoor mixes prioritize moisture regulation and pest resistance, often featuring additives like yucca extract and reduced bark to deter gnats. Outdoor mixes focus on durability, quick‑release fertilizers, and greater water‑holding capacity to withstand weather fluctuations. Selecting the right type ensures your plants receive the appropriate support for their growing environment.