Comparison: Best Organic Seed Starting Mix (Updated | Nov 11th)
But with so many options labeled “organic” and “perfect for seedlings,” how do you choose? We’ve tested the top contenders to find out which organic seed starting mixes truly deliver—giving your tiny sprouts the best shot at life without harsh chemicals or guesswork.
- Best for compact expandable: Back to the Roots Organic Seed Starting
- Best for 3-in-1 eco mix: Back to the Roots 3-in-1 Seed Starting Mix 6 Quarts
- Best for espoma root boost: Espoma Organic Seed Starter Premium Potting Soil Mix – All Natural & Organic Seed Starting Mix with Mycorrhizae. For Organic Gardening
- Best for coconut coir brick: Burpee Organic Coconut Coir Concentrated Seed Starting Mix
- Best for bulk seed starter: Espoma 16 qt. Organic Seed Starter Premium Potting Mix (2)
- Best for smart garden kit: Promix Premier Horticulture Organic Pro Seed Starting Mix; 16 qt with My Garden Pool PH Soil Test Strips 20 ct
- Best for three-month feed: Premier Horticulture 1016041RGCE Organic Pro Seed Starting Mix
Product Comparison: Best Organic Seed Starting Mix
Back to the Roots Organic Seed Starting, Compressed Block expands to 12 Quarts, Made for Herbs, Veggies, Flowers
- A balanced pH, which means it’s truly all-purpose. Use alone or as an amendment for anything in a pot or in the ground — vegetables, flowers, herbs, and even starting seeds.
- Expands to 12 Quarts
- Peat Free OMRI Listed, assuring organic production, handling, and processing
- 100% SATISFACTION GUARANTEE: If you are not satisfied or have any issues with this product, just shoot us a note and our dedicated customer support team will make sure we get you growing or send you a refund/replacement.
- 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.
Back to the Roots 3-in-1 Seed Starting Mix 6 Quarts, 100% Organic & USA Made for Herbs, Veggies, Flowers, w/Nutrient Rich Plant Food, Worm-Castings, & Moisture Controlling Yucca Brown
- NUTRIENT-RICH, NATURAL, AND ORGANIC SOIL: Grow a bountiful garden in your home with the Back to the Roots All-Purpose Natural and Organic Peat-Free 3-in-1 Seed Starting Mix, packed with the nutrients needed for your plants, flowers, and vegetables to thrive
- MYCORRHIZAE, YUCCA EXTRACT, AND COCONUT COIR FOR STRONG ROOT DEVELOPMENT: This organic potting soil has mycorrhizae, coconut coir, and yucca extract which enhances the root’s uptake of water and the nutrients required by your plants for growth
- FEATURES pH BALANCING DOLOMITIC LIMESTONE: The dolomitic limestone of this potting soil has a combination of calcium carbonate and magnesium carbonate which effectively neutralizes acidity and prevent nutrient deficiency
- ZERO-RISK GARDENING AND GREAT FOR THE PLANET: Made in the USA and 100% guaranteed to grow; If you have any problems, we will send you a new bag to get you growing; Mined peatlands contribute yearly CO2 emissions equivalent to what cars all over the world are releasing — that’s why we think it’s so important to leave peat alone and offer the 1st premium, 100% peat-free soil in the market
- THE PERFECT GIFT: The perfect holiday gift, it comes in a beautiful packaging so that it’s ready to be given to foodie, garden-loving and eco-conscious friends and family; This kit is also part of our Grow One Give One campaign, simply share a picture on social media, tag us and use the campaign hashtag, and we’ll donate a kit to a classroom of your choice
Espoma Organic Seed Starter Premium Potting Soil Mix – All Natural & Organic Seed Starting Mix with Mycorrhizae. For Organic Gardening, 16 qt, bag – Pack of One
- CONTAINS: This organic Seed Stating soil mix is a rich blend of sphagnum peat moss & perlite with yucca extract and lime to ensure correct pH.
- MYCO-TONE: A blend of endo & ecto mycorrhizae.
- WHEN TO USE: Use to germinate and start seeds. Great for flower, vegetable, herb & more plant types. Can also be used to root stem and leaf cuttings.
- PROMOTE ROOT GROWTH: Organic seed starter mix ensures ideal moisture retention and aeration.
- ORGANIC GARDENING: Contains a rich blend of only the finest natural ingredients. No synthetic plant foods or chemicals are used.
Burpee Organic Coconut Coir Concentrated Seed Starting Mix, 16 Quart
- ORGANIC COCONUT COIR: Made from recycled coconut husks, coir is a light, sustainable growing medium that holds the perfect amount of moisture for starting seeds. 100% biodegradable soil alternative. Environmentally-friendly and a renewable alternative to peat moss. OMRI listed and certified organic.
- IDEAL GROWING MIX: Improve seed germination and root growth with this premium coconut fiber mix, which improves nutrients absorption! Great for flower, vegetable, herb & more plant types. OMRI listed. Naturally disease and pathogen resistant, it will help you grow healthy live plants.
- EASY TO STORE & EXPAND: Each compact coconut coir brick expands into 8 quarts of seed starting mix, providing 16 quarts total. Just add water to expand! Dehydrated bricks save space until planting. Once expanded, coconut coir provides a quality growing medium for all types of plants – indoor plants, house plants, outdoor plants, and more!
- NATURALLY CONSERVES WATER: Renewable coco coir has excellent moisture retention and better air circulation than peat. This eco-friendly, premium seeds starting mix combines well with other potting soil and compost for container plants & raised beds.
- 100% GUARANTEED: Burpee is committed to the success of all gardeners. We treat each order with care to ensure healthy seeds, plants, soil mixes & gardening supplies are sent in excellent condition. If you are unsatisfied with your purchase, we aim to make it right!
Promix Premier Horticulture Organic Pro Seed Starting Mix; 16 qt with My Garden Pool PH Soil Test Strips 20 ct, and Gardening Claw Gloves and Garden-IQ, Smart Gardening AI Assistant!
- 🌿Organic and All-Natural Ingredients: Carefully selected to provide your seeds with a healthy, chemical-free start.
- 🌱Enriched with Mycorrhizae: For enhanced nutrient and water absorption, promoting stronger root development and plant growth.
- 🧪Easy pH Monitoring: Comes with 20 pH soil test strips for optimal soil condition management.
- 🌻Versatile Use: Ideal for a wide range of plants, ensuring your garden’s diverse needs are met.
- 🌱Promotes Healthy Seeds: Specially formulated to encourage vigorous seed germination and growth.
- 🌿Eco-Friendly Packaging: Committed to sustainability, our packaging is designed to minimize environmental impact.
- 🧠 Garden-IQ, Smart Gardening AI Assistant: Get smart advice and solutions tailored to your gardening needs.
- 🧤Superior Gardening Claw Gloves: In addition to the fertilizer and pH test strips, this package also includes My Garden Pool Superior Gardening Claw Gloves, offering maximum protection and comfort for your hands while working in the garden.
Premier Horticulture 1016041RGCE Organic Pro Seed Starting Mix, 16 Quart
- Size : 16 Quart
- Ingredients : Organic Fertilizer
- Organic premium seed starting mix is ideal for perennials and flowering shrubs
- Contains an organic fertilizer that gradually feeds for up to 3 months
- Contains MYCOACTIVE to stimulate vigorous growth and greater resistance
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 key factors should I look at when picking an organic seed starting mix?
Focus on the mix’s pH balance, presence of beneficial microbes like mycorrhizae, and whether it’s peat‑free for sustainability. Also compare the expansion ratio or total volume you’ll receive, as it impacts cost per quart. Finally, check for guarantees or return policies that protect your purchase.
How do compressed block mixes differ from loose‑bag mixes?
Compressed blocks, such as the Back to the Roots 12‑quart block, start compact and expand with water, saving storage space and reducing waste. Loose‑bag mixes, like Burpee’s 16‑quart coir brick, are already in a bulk form and may be easier to scoop directly into containers. Both deliver similar nutrients, but blocks are handy for small spaces while bags suit larger projects.
Which product gives the best value for a medium‑sized garden?
The Burpee Organic Coconut Coir Concentrated Mix expands to 16 quarts from a compact brick, offering a high volume for a modest price and excellent moisture retention. Back to the Roots 3‑in‑1 6‑quart mix provides added nutrients and a peat‑free formula but at a lower total volume. For sheer quantity and cost efficiency, the Burpee option usually wins.
Do these mixes have different pH‑balancing features?
Yes. Back to the Roots 3‑in‑1 includes dolomitic limestone to neutralize acidity, while the Espoma Seed Starter mixes rely on lime and peat moss for a balanced pH. The coconut coir mixes are naturally near neutral, making them suitable for most seed types without additional adjustments.
How important are mycorrhizae and other root‑enhancing additives?
Mycorrhizae form a symbiotic relationship with plant roots, improving water and nutrient uptake, which can speed germination and strengthen seedlings. Several mixes—Back to the Roots 3‑in‑1, Espoma Premium, and Promix Premier—list mycorrhizae or MYCO‑ACTIVE as key ingredients. Including these microbes generally leads to healthier, more resilient plants.
Are any of these mixes completely peat‑free, and why might that matter?
Back to the Roots 3‑in‑1, Burpee Coconut Coir, and the Promix Premier mixes are certified peat‑free, using coconut coir or other organic fibers instead. Peat extraction harms wetlands and releases carbon, so peat‑free options are more environmentally friendly. They also tend to offer better aeration and water retention for seed starting.
What should I know about the expansion sizes and storage of these products?
Compressed blocks expand to a larger volume—Back to the Roots grows from a compact block to 12 quarts, and Burpee’s brick expands to 16 quarts—saving shelf space before use. Loose mixes come pre‑expanded, which can be bulkier but ready to fill trays immediately. Choose based on your storage constraints and how quickly you plan to start planting.
Do these brands provide any satisfaction guarantees or warranties?
Back to the Roots offers a 100% satisfaction guarantee with options for refunds or replacements, and they also run a Grow One Give One program. Burpee promises a 100% guarantee to replace unsatisfied orders. Espoma and Promix also have customer support policies, though specifics vary, so reviewing each brand’s return terms is advisable.