How to Make the Best Soil Block Mix for your Seedlings

Soil blocks are a fantastic alternative to traditional seed-starting methods. They’re environmentally friendly, reduce transplant shock, and promote healthier root development. To ensure your seedlings get the best start, it’s crucial to use a high-quality soil block mix. Let me show you my secret recipe for soil-blocking success!

soil blocking mix

Soil Blocking + Seed Starting

Over the years, we have tried so many soil mixes when it comes to seed starting. From complex blends that involve tons of ingredients, expensive soils etc. For the past few years, now, we have simplified our mix and have had consistently great results!

Whether you are creating soil blocks or have some plastic tray blocks to use up, this mix will work! We just prefer soil blocking because it saves so much space in our greenhouse the trays we use from Bootstrap Farmer are super durable, able to be washed and sanitized in the dishwasher, stacked up and stored away, and reused over and over again. I also really love the mesh trays for bottom watering my blocks. Here is an entire blog post dedicated to all our Favorite Soil-Blocking Tools and Resources.

The Ultimate Peat-Free Soil Blocking Recipe Mix

Soil blocking is a gardening technique that utilizes compact blocks of soil instead of traditional pots. It’s an eco-friendly alternative that promotes healthier plant growth. If you’re looking to create the perfect soil-blocking mix, we’ve got you covered. Our recipe includes peat-free soil/compost, wool, and cinnamon, offering a nutrient-rich and sustainable option for your plants.

Soil Mix Ingredients:

  • Peat-free soil/compost: Peat bogs are valuable ecosystems, and using peat-free alternatives helps conserve them. Look for a high-quality, peat-free soil or compost blend. I have been able to find my favorite peat-free Fox Farm Cocoa Loco soil at our local Home Depot. This has a bit of coconut coir in it already, too.
  • Wool: Wool is an excellent addition to soil-blocking mixes. It retains moisture, improves soil structure, and provides nutrients as it decomposes. Use clean, natural wool without any dyes or chemicals. We happen to have wool around after we sheer sheep and have started using it in our mixes to help with moisture retention. If you don’t have access to wool, you could also use the same amount of coconut coir. Also sold in garden centers to help with moisture and soil structure. Or you can find wool pellets online.
  • Cinnamon: Cinnamon is a natural fungicide and can help prevent damping-off disease in seedlings. It also adds a pleasant scent to your soil mix.

Soil Blocking Mix Recipe

Eco-friendly and Nutrient-Rich Soil Recipe


  • 1 Bin


  • Fill a large container or bin with peat-free soil/compost. Use a mix that is well-draining but moisture-retentive.
  • Add finely shredded wool or coconut coir to the soil mix. Aim for a ratio of about 1 part wool to 10 parts soil.
  • Sprinkle a small amount of ground Cinnamon (about 1 teaspoon per gallon of soil mix).


  • Mix everything together well so that the cinnamon and wool are evenly distributed. Then add enough water to make your mix about like the constancy of peanut butter. (2.5-3 Parts)

Benefits of this Recipe:

  • Eco-friendly: By using peat-free soil/compost, you’re helping to protect peat bogs and reduce carbon emissions.
  • Nutrient-rich: Wool provides slow-release nutrients to your plants, promoting healthy growth.
  • Disease prevention: Cinnamon acts as a natural fungicide, reducing the risk of damping off disease in seedlings.

Creating your soil-blocking mix using peat-free soil/compost, wool, and cinnamon is a sustainable and effective way to support healthy plant growth. Not only does it benefit your plants, but it also helps protect the environment. Give this recipe a try and watch your garden thrive!

soil blocker in soil

Questions People are asking about Soil Blocking Mixes

Can I use garden soil for soil blocks?

It’s not recommended. Garden soil can contain pests, diseases, and weed seeds, which can harm your seedlings. It’s best to use a sterile soil mix for soil blocks.

How long does soil block mix last?

If stored in a cool, dry place, soil block mix can last for several months. However, it’s best to make fresh mix for each growing season for optimal results.

Can I reuse soil block mix?

Yes, you can reuse soil block mix for a few seasons. After using it, allow it to dry out completely, then store it in a sealed container. Before reusing, moisten the mix and add fresh compost as needed.

Can I add fertilizer to the soil block mix?

It’s not necessary, as the compost provides enough nutrients for seedlings initially. However, you can add a diluted liquid fertilizer when watering if needed.

Can I substitute ingredients in the soil block mix?

Yes, you can adjust the recipe based on availability and preferences. Just ensure the mix remains light, airy, and well-draining.

Pin this Recipe for later!

soil blocking mix recipe pin

Other Gardening Posts:

The Best Soil Blocking Equipment

Soil Blocking 101

Gardening with No Weeds

Making Carrot Seed Tape

Our Top 12 Gardening Tools

My Favorite Gardening Shirts

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Affiliate Disclosure & Content Disclaimer

This post may contain affiliate links from a paid sponsor, Amazon or other program. When you use these links to make a purchase I earn a small commission at no extra cost to you. This allows me to continue creating the content that you love. The content in this article is created for information only and based on my research and/or opinion. 

Emily T.

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