Comparison: Best Costco Organic Potting Soil (Updated | Nov 11th)
But with a few different options lining those warehouse shelves, how do you know which one’s worth your money? We’ve dug into the bags, tested the blends, and compared ingredients, value, and performance so you don’t have to. Whether you’re potting perennials or starting seedlings, let’s find the organic mix that delivers real results without breaking the bank.
- Best for peat-free power: Back to the Roots 100% Organic Potting Mix (Value 12 Quart) | Premium Blend | Made in The USA
- Best for quick-feed outdoor: Miracle-Gro Organic Outdoor Potting Mix
- Best for expandable coco boost: 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 water balance indoor: Miracle-Gro Organic Indoor Potting Mix
- Best for pet-safe indoor: Back to the Roots 100% Organic Indoor Potting Mix (Value 12 Quart) | Promotes Healthy Houseplant Growth| Made in The USA
- Best for bulk outdoor boost: Miracle-Gro Organic Outdoor Potting Mix
- Best for mycorrhizae rich: Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. For Organic Gardening
- Best for value pack outdoor: Miracle-Gro Organic Outdoor Potting Mix
- Best for versatile topsoil: Michigan Peat 40 Pound Bag Garden Magic Organic Planting Potting Top Soil Blend Mix for Indoor and Outdoor Gardening and Landscapes
- Best for super concentrated soil: Compressed Organic Potting Soil for Garden
Product Comparison: Best Costco Organic Potting Soil
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)
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!
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)
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 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)
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 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)
Michigan Peat 40 Pound Bag Garden Magic Organic Planting Potting Top Soil Blend Mix for Indoor and Outdoor Gardening and Landscapes, White
- Ready-to-Use for All Planting Needs: This general-purpose potting mix is ready to use out of the bag, making it perfect for both indoor and outdoor planting without any additional preparation
- Optimal Moisture Retention & Drainage: Designed to allow excess water to drain effectively while retaining moisture, promoting healthy plant growth during dry seasons
- High-Quality Soil Blend: Features a dark blend of reed sedge peat, perlite, and sand, offering the best conditions for plant health and soil structure
- Perfect for All Gardeners: Developed for both new and experienced home gardeners, this soil mix enhances plant growth in various environments and gardening projects
- Improves Soil Quality: Ideal for loosening heavy clay soils and enhancing moisture in light soils, making it perfect for use as a top dressing to fill holes in lawns and garden beds
Compressed Organic Potting Soil for Garden, Plants & Vegetables – Expands 4x When Mixed with Water – Indoor or Outdoor Use – Plant Food Mix Derived from Natural Coconut Coir & Worm Castings Fertilizer
- A LITTLE DOES A LOT – Easy to use compressed soil granules quickly expand up to 4X and make up to 3 gallons of soil. Light, compact, easy to carry, resealable bag saves space.
- NOURISH & SEE THEM FLOURISH – Packed with every essential nutrient plus 55+ trace minerals, this concentrated super soil feeds and grows strong beautiful vibrant plants better than ever!
- FAST ACTING & LONG LASTING – Easy to wet and stays moist 3X longer. Living soil gets water, air and nutrients to roots on demand. Perfect for all seeds, starts, transplants, containers, raised beds and gardens!
- TRULY ORGANIC YOU CAN TRUST – 100% natural ground coconut coir, worm castings, compost, humic acids, amino acids, kelp and beneficial GroBiotics including mycorrhizae give your soil, flower, vegetable, herb, fruit, tree, shrub, raised bed, outdoor or indoor potted house plants and more a super-boost.
- EASY to USE – Just add water 1:1 to compressed soil to expand up to 4X. Use 1 tsp for small seeds, 1 tbsp for large seeds, 1/4 cup per seedling, 1 cup per small plant, and 4 cups per gallon plant. Use expanded soil straight or blend 1:2 with other soil. Prevents overwatering, re-wets easily, and stays moist 3X longer. As mulch or top dress, apply 1/4 inch expanded soil or spread compressed soil and water. A 2 lb bag covers up to 20 sq ft.
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 blends that are peat‑free, contain moisture‑retaining ingredients like coco coir or yucca extract, and include mycorrhizae for root health. Products such as Back to the Roots Indoor Mix and Wonder Soil highlight these traits, making them ideal for houseplants. Also check for pet‑safe formulas that reduce gnats and pests.
How does a peat‑free mix compare to a traditional peat‑based mix in terms of performance?
Peat‑free mixes, like Back to the Roots and Wonder Soil, use upcycled plant material or coco coir, offering similar water retention while lowering carbon footprint. Traditional peat mixes, such as Miracle‑Gro Outdoor, often provide quick‑release fertilizers but rely on harvested peat, which is less sustainable. Both can perform well, but peat‑free options are better for eco‑conscious gardeners.
Which product gives the best value for larger outdoor container gardens?
Miracle‑Gro Organic Outdoor Potting Mix in the 25‑qt bag fills three 10‑inch containers, delivering a low cost per volume. The bundled two‑bag 16‑qt option also offers good value for medium‑size projects. If you prefer a peat‑free alternative, Wonder Soil expands fourfold from a compact bag, saving space and money on shipping.
Are there mixes that include built‑in fertilizer, and how long does it last?
Yes, Miracle‑Gro Organic Outdoor and Indoor mixes contain a quick‑release natural fertilizer that feeds plants for up to two months. Back to the Roots and Wonder Soil rely on organic amendments like kelp and worm castings, providing slower, steady nutrition without a defined timeframe. Choose based on whether you want an immediate boost or a long‑term feeding schedule.
What are the key differences between Back to the Roots Indoor and Outdoor mixes?
Both are 100 % organic and peat‑free, but the Indoor version emphasizes yucca extract for moisture control and pet‑safe formulation, while the Outdoor blend is geared toward larger containers and includes a quick‑release fertilizer. The Indoor mix also highlights mycorrhizae for root development in houseplants. Selecting the right one depends on where you’ll be growing your plants.
How important is mycorrhizae in a potting soil, and which products contain it?
Mycorrhizae form a symbiotic relationship with plant roots, improving nutrient uptake and drought tolerance. Back to the Roots Indoor Mix and Espoma Organic Potting Soil both list mycorrhizal inoculants. Including this ingredient can give a noticeable edge in plant vigor, especially for seedlings and fruit‑bearing varieties.
Is there a compact, space‑saving option for gardeners with limited storage?
Wonder Soil’s compressed coco coir bag expands up to four times its size when hydrated, making it ideal for small sheds or apartments. The compressed organic soil from the “Compressed Organic Potting Soil” brand offers a similar expansion ratio and comes in a resealable bag for easy storage. Both provide nutrient‑rich mixes without bulk.
What factors affect the overall cost‑effectiveness of a potting mix?
Consider the volume of soil per bag, the presence of built‑in fertilizer, and any added organic amendments that reduce the need for supplemental feeding. Larger bags like Miracle‑Gro’s 25‑qt option lower the price per quart, while peat‑free mixes that expand (e.g., Wonder Soil) reduce shipping weight and storage costs. Balancing price with performance and sustainability will give you the best overall value.