Do Soil Blocks Fall Apart?

Soil blocks are eco-friendly alternatives to plastic pots and containers. But many gardeners fear that their soil blocks will crumble and fall apart during use, resulting in messy clumps of soil that cannot independently support plant growth. 

Soil blocks can fall apart when exposed to excessive levels of moisture. Alternatively, they can become crumbly and fall apart when left to dry for extended periods. Still, the soil composition of any given block is the primary determining factor in its stability.

This article will explore why some soil blocks fall apart and discuss how gardeners can ensure that their soil blocks remain stable.

Understanding the Composition of Soil Blocks

Manufacturers create soil blocks of several elements, including:

  • Peat
  • Perlite
  • Compost
  • Garden soil

These are the primary components that makeup soil blocks. However, these blocks also contain a few additional elements, but to a lesser extent. 

For example, soil blocks typically have:

  • Sand
  • Dolomitic lime
  • Phosphate
  • Blood meal

The primary purpose of these additional components is to provide the blocks with nutrients that help plants grow. But manufacturers add sand in small quantities to alter soil texture and allow soil blocks to drain more evenly.

As you can see, soil blocks contain different combinations of soils and fertilizers, and as a result, they can fall apart far more easily than plastic or ceramic gardening containers. 

After all, when soil experiences high moisture, it often turns into mud, a malleable substance that doesn’t hold up to pressure. In fact, water is one of the most influential factors affecting soil block stability.

Factors Affecting Stability: Moisture, Composition, Packing

There are quite a few factors that affect the integrity of a soil block.

The most crucial of these are:

  • Moisture level
  • Soil composition
  • Packing methods

If you’re concerned about your soil blocks falling apart, you’ll want to take a moment to review these factors:

Moisture Level

If you’ve tried to till soil after rainfall, you’re likely familiar with how unstable dirt gets when drenched with water. And if you’ve ever attempted to grow seedlings in cracked, dry soil, you’re also likely familiar with how an absence of moisture can lead to premature plant death.

Just as moisture is crucial to maintaining a healthy and robust garden, it’s also vital to producing stable soil blocks. Blocks made with soil that’s too dry won’t stick together to form functional blocks, but overly wet soil may take ages to set.

Muddy soil can also develop fungal problems during the setting process, making the final products unusable.

Soil Composition

Getting the soil composition right for soil blocks takes practice and a tried-and-true recipe. Each element should work together to create a stable final product.

For example, if you use too much sand in your soil block mixture, the resulting blocks can crumble at the slightest touch. But using too much compost or manure fertilizer can make the components stick together into dense clumps, making root growth virtually impossible.

Using your hands (or the wrong tools) to create soil blocks can also impact stability.

Packing Methods

Attempting to hand-pack soil blocks can result in blocks with soil too dense for root growth. It can also produce blocks that crumble before you ever have a chance to sow seeds.

That’s why soil block producers use precise tools to create blocks. These make it easy to develop identically-sized blocks with the ideal density for plant growth. 

How to Prevent Soil Blocks From Falling Apart

Ensuring that your soil blocks remain stable requires precise soil mixing, appropriate construction tools, and a little maintenance.

So, if you’re eager to keep your soil blocks compact, you’ll want to:

  • Use a tested mixture recipe.
  • Invest in the right tools.
  • Spray water onto the blocks to keep them moist.
  • House blocks in fabric containers.
  • Purchase pre-made blocks from reputable retailers.

Let’s explore these steps in greater detail to ensure that your soil blocks don’t crumble or become a muddy mess:

Use a Tested Mixture Recipe

Attempting to make soil blocks with a recipe is much like making a delicious cake without a recipe—messy and often disastrous. 

If you’d like to make your own soil blocks, you’ll want to use a reputable soil recipe. Much like the recipe for a cake, this information will tell you how much of each ingredient you’ll need.

If you’ve never attempted to make DIY soil blocks before, you might also want to check out a video guide to help you get started. This video offers plenty of helpful tips to help you create top-notch soil blocks at home: 

Invest in The Right Tools

Creating soil blocks by hand can be a time-consuming and messy process. It can also result in blocks that aren’t identically sized and crumble easily. For these reasons, you’ll want to invest in a manual soil block tool when creating blocks for your garden.

Fortunately, several soil block tools are available, each suited to various gardening needs. Depending on the size of your block mixture, you can produce a few dozen or several hundred blocks in one go while using a soil block maker. 

Spray Water Onto the Blocks to Keep Them Moist

When soil blocks dry out, they become brittle. For that reason, gardeners will want to keep blocks moist. While it is possible to keep blocks wet by dipping them in water or spraying them with a garden hose, it’s challenging to control moisture levels using these methods.

As such, it’s often better to use a spray bottle filled with water to keep the exterior of soil blocks moist. While letting the outside layer of these blocks dry out slightly is fine, letting them stay dry for days or weeks can significantly decrease their stability.

House Blocks in Fabric Containers

Though soil blocks reduce the need for containers, you can pair soil blocks with all-natural fabric containers to help make them more stable.

You can purchase pre-made fabric containers or choose to make your own. Be sure to get one with breathable fabric, allowing moisture to evaporate and escape, reducing the risk of root rot.

Purchase Pre-Made Blocks From Reputable Retailers

Creating your soil blocks can be a hit-or-miss process, especially during your first few tries. Besides, investing in the materials and tools needed to make stable DIY soil blocks can be pricier than purchasing pre-made blocks.

If you’d like to use soil blocks but are not interested in making them yourself, you’ll want to buy pre-made blocks from reputable retailers. Fortunately, many small-scale local plant nurseries create and sell high-quality soil blocks. 


Soil blocks can fall apart if they don’t contain the proper ratio of soil types. They can also become fragile when dry or overly wet. Hand-packed soil blocks tend to fall apart more quickly than those packed with tools.

There are several ways to keep soil blocks stable. Utilizing a soil block recipe is a great place to start. Gardeners may also want to use a spray bottle to keep blocks moist (but not soaked), house blocks in fabric containers, or purchase pre-made blocks from reputable suppliers.

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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