Soil Blocking: A Better Way to Start Seeds Indoors

Soil blocking is a seed-starting technique that uses cubes of compressed soil to grow healthy, vigorous plants. It’s my go-to method for starting vegetable, flower, and herb seeds and produces a lot of seedlings without the need for plastic pots or cell packs. The cubes of soil are made using metal soil blockers which come in a variety of sizes. Soil blocking isn’t difficult but there are a few points to keep in mind to boost success. Below you’ll learn all about soil blocking and the best way to make sturdy cubes of soil for seed starting.

Soil blocking, a seed-starting technique developed and popularized by Eliot Coleman, uses small cubes of soil to grow seedlings. The block of soil is both the growing medium and the container and results in robust seedlings. The cubes are created with durable metal soil blockers that compress the growing mix into 3/4 inch, 1 1/2 inch, 2 inch, or 4 inch blocks. Depending on the dibble, the piece of plastic that makes an indentation in the top of the blocks as they’re formed, you can make soil blocks for seed starting (the rounded dibble) or transplanting (the square dibble). More on this below. I’ve had my soil blockers for many years and use them each spring and summer to produce thousands of soil cubes for seed starting.

If you’re on the fence about soil blocking, let me share some of the many benefits of this seed-starting method. Here are 5 reasons to consider getting started with soil blocking:

1. Produces vigorous seedlings with a dense root system – Soil blocking offers more root space than cell packs or plug trays and the roots are air pruned when they reach the outside edge of the soil cube. This results in dense root growth inside