Comparison: Best Costco Potting Soil Miracle Gro (Updated | Nov 11th)
If you’ve ever stood in the garden aisle wondering which potting soil truly delivers the best results without breaking the bank, you’re not alone. We put two heavyweights to the test: Costco’s bulk-friendly potting mix and the trusted classic, Miracle-Gro. Spoiler: it’s not just about price.
- Best for growth boost mix: Miracle-Gro Potting Mix
- Best for organic quick-feed: Miracle-Gro Organic Outdoor Potting Mix
- Best for moisture control formula: Miracle-Gro Moisture Control Potting Mix
- Best for all-purpose feed: Miracle-Gro Potting Mix
- Best for indoor gnat-resistant: Miracle-Gro Indoor Potting Mix
- Best for houseplant perlite blend: Miracle-Gro Houseplant Potting Mix: Fertilized
- Best for cactus drainage mix: Miracle-Gro Cactus
- Best for large-scale organic: Miracle-Gro Organic Outdoor Potting Mix
- Best for gnat-resistant soil: Miracle-Gro Houseplant Potting Mix – Fertilized Soil
- Best for seed starter blend: Miracle-Gro Seed Starting Potting Mix
Product Comparison: Best Costco Potting Soil Miracle Gro
Miracle-Gro Potting Mix, For Container Plants, Flowers, Vegetables, Annuals, Perennials, Shrubs, Feeds for up to 6 Months, 16. qt., 2-Pack
- Miracle-Gro Potting Mix feeds container plants for up to 6 months so you get more blooms for more color (vs. unfed plants)
- How to use: To use this potting medium, fill a container about 1/3 full with potting mix, place your plant in the soil, and fill the rest of the pot, pressing lightly
- What’s included: This bundles includes two 16 qt. bags of Miracle-Gro Potting Mix, each able to fill one 12-inch container (exact amounts may vary based on root ball size)
- Where to Use: Use this home gardening product with all types of container plants, including annual and perennial flowers, vegetables, herbs and shrubs
- This potting soil mix Grows Plants Twice As Big (vs. unfed plants)
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 Moisture Control Potting Mix, For Container Plants, Protects against Over- and Under-Watering, 8 qt., 2-Pack
- Miracle-Gro Moisture Control Potting Mix feeds plants for up to 6 months and Grows Plants Twice As Big! (vs unfed plants)
- This potting medium protects against over and under watering; also absorbs up to 33% more water than basic potting soil* with exclusive AquaCoir Formula (*soil that does not contain sphagnum peat moss, coir, and wetting agent)
- Use this gardening product with all types of container plants, including flowers, vegetables, annuals, perennials, and shrubs
- To use this potting soil, fill a container about 1/3 full with potting mix; place your plant in the pot and cover with more mix
- This bundle comes with two 8 qt. bags of Miracle-Gro Moisture Control Potting Mix; each fills two 8-inch containers (exact amounts may vary depending on the size of the root ball)
Miracle-Gro Potting Mix, For Indoor or Outdoor Potted Plants, Flowers, Vegetables, Shrubs, Annuals, and Perennials, Feeds Up to 6 Months, 8 qt.
- Feeds all potted plants: Miracle-Gro Potting Mix feeds all types of potted plants, including flowers, vegetables, shrubs, annuals, and perennials for up to 6 months
- Promotes growth: This potting soil Grows Plants Twice As Big! (vs. unfed plants)
- Boosts color: Get more blooms for more color (vs unfed plants)
- Application: To apply this potting medium, fill a container about 1/3 full with potting mix, place your plant in the soil, and fill the rest of the pot, pressing lightly; water thoroughly
- Coverage: Each 8 qt. bag of Miracle-Gro Potting Mix fills two 8 inch containers (exact amounts may vary depending on the size of the root ball)
Miracle-Gro Indoor Potting Mix, Blended for a Variety of Houseplants, Feeds for up to 6 Months, 16 qt., 2-Pack
- Miracle-Gro Indoor Potting Mix feeds houseplants for up to 6 months and is designed to be less prone to gnats (contains no compost or bark, which are known to shelter fungus gnats)
- This potting mix contains coconut coir, which holds and releases water and helps soil re-wet
- Where to use: Blended for a wide variety of indoor container plants, including climbing, foliage, flowering, and tropical plants
- How to use: To use, fill a container about 1/3 full with potting mix; add more mix after placing your plant in the pot
- What’s included: This bundles includes two 16 qt. bags of Miracle-Gro Indoor Potting Mix, each able to fill one 12-inch containers (exact amount may vary based on the root ball size)
Miracle-Gro Houseplant Potting Mix: Fertilized, Perlite Soil for Indoor Gardening, Designed to Be Less Prone to Gnats, 4 qt.
- Growing indoors is easy under the right conditions; Miracle-Gro Houseplant Potting Mix combines key elements plants need to thrive
- Recommended for growing beautiful indoor houseplant varieties like Pothos, Spider Plants, Monstera, Philodendron, English Ivy and more
- This indoor plant soil is less prone to gnats, thanks to the combination of perlite, sphagnum and peat moss that’s just right
- Certified by the Mulch & Soil Council as a quality product in compliance with industry standards
- A single 4-qt bag fills an 8-inch container; for even more spectacular results, start regular feedings with Miracle-Gro Plant Food 30 days after planting
Miracle-Gro Cactus, Palm and Citrus Potting Mix, for Indoor or Outdoor Potted Plants, Great for Succulents, 8 qt., 2-Pack
- Miracle-Gro Cactus, Palm & Citrus Potting Mix features a fast-draining formula and is enriched with Miracle-Gro Plant Food
- This fast-draining formula is blended to help promote successful growing of cacti, potted palms, citrus, and other succulents
- This cactus potting mix is designed for indoor and outdoor container plants, including cacti, palm plants, citrus trees, and succulents
- To use this succulent soil mix, fill a pot with a drainage hole 1/3 full of mix, top with more mix after placing plant, and press lightly
- This bundle includes two 8 qt. bags of Miracle-Gro Cactus, Palm & Citrus Potting Mix, each able to fill two 8-inch containers (amounts may vary based on root ball size)
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)
Miracle-Gro Houseplant Potting Mix – Fertilized Soil, Designed to be Less Prone to Gnats, 4 qt. (2-Pack)
- Growing indoors is easy under the right conditions; Miracle-Gro Houseplant Potting Mix combines key elements plants need to thrive
- This indoor plant soil is less prone to gnats thanks to the combination of perlite, sphagnum and peat moss
- Recommended for growing beautiful, indoor houseplant varieties like pothos, spider plants, monstera, philodendron, english ivy, and more
- Certified by the Mulch & Soil Council as in compliance with industry standards
- Bundle includes two bags of Miracle-Gro Houseplant Potting Mix
Miracle-Gro Seed Starting Potting Mix, 8 Quarts (Pack of 2), For Use in Containers
- Specially formulated for fast root development
- Enriched with Miracle-Gro Plant Food
- Excellent for starting cuttings
- Use when starting from seed and with leaf, stem or root cuttings
- This bundle includes two 8 qt. bags of Miracle-Gro Seed Starting Potting Mix
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
How do I choose between the regular Miracle‑Gro Potting Mix and the Organic Outdoor version?
The regular mix includes a quick‑release synthetic fertilizer that feeds plants for up to six months, making it ideal for vigorous growth and vibrant blooms. The Organic Outdoor mix uses a natural fertilizer and responsibly sourced peat, feeding for about two months, which appeals to gardeners seeking an eco‑friendly option. Consider the type of plants, your preference for synthetic versus organic nutrients, and how often you plan to fertilize when making your choice.
What are the benefits of the Moisture Control Potting Mix compared to standard mixes?
Moisture Control features an AquaCoir formula that absorbs up to 33 % more water and helps prevent both over‑ and under‑watering, which is especially useful for busy gardeners. It also feeds plants for six months and promotes growth twice as large as unfed plants. If you struggle with consistent watering, this mix can reduce the need for frequent checks.
Is the Indoor Potting Mix better for houseplants than the regular potting mix?
The Indoor mix is formulated without compost or bark, reducing the risk of fungus gnats, and includes coconut coir for steady water release. While both mixes feed for up to six months, the Indoor version’s low‑gnat design makes it a safer choice for indoor environments. For plants that are sensitive to pests, the Indoor mix offers added peace of mind.
How much coverage do the different bag sizes provide, and which is most cost‑effective?
Eight‑quart bags typically fill two 8‑inch containers, while sixteen‑quart bags can fill one 12‑inch pot; the 25‑quart Organic Outdoor bag covers roughly three 10‑inch containers. Buying larger bags usually lowers the per‑quart price, so if you have multiple containers or plan to repot regularly, the 25‑quart option gives the best value. Compare the total volume you need against the bag size to avoid waste.
Can I use the Cactus, Palm & Citrus Mix for regular vegetables or flowers?
The Cactus, Palm & Citrus mix is designed for fast‑draining conditions, which are ideal for succulents but may not retain enough moisture for moisture‑loving vegetables or flowering annuals. For those plants, a standard or moisture‑control mix that holds more water is preferable. Use the specialized mix only for plants that require excellent drainage.
What makes the Seed Starting Potting Mix different from other Miracle‑Gro mixes?
Seed Starting mix is formulated for rapid root development and includes extra plant food to support seedlings and cuttings. It lacks the heavy fertilizer load of the regular potting mixes, providing a gentler start for young plants. This makes it the best choice when you’re germinating seeds or propagating cuttings.
Is there a noticeable price difference between the organic and non‑organic mixes, and does it affect performance?
Organic mixes generally carry a slightly higher price due to the natural fertilizer and certified peat, but they perform comparably for most container plants over a two‑month feeding period. Non‑organic mixes offer longer feeding intervals (up to six months) and may produce faster growth, which can justify the lower cost for heavy‑feeding gardeners. Choose based on your budget and whether you prioritize organic ingredients.
How important is the bag bundle size when planning a garden project?
Bundle sizes (e.g., two 8‑qt bags vs. two 16‑qt bags) affect both convenience and overall cost; larger bundles reduce packaging waste and often lower the cost per quart. For a single large container, a 16‑qt bag may be sufficient, while multiple small pots benefit from 8‑qt bags. Assess the number and size of your containers to select the most efficient bundle.