How to Make Soil Mix for Your Soil Blocks
Soil blocks let you germinate seeds and grow seedlings all in one spot!
When you grow with seed blocks there are no seed trays, no shifting to pots, and minimal risk of transplant shock. How can you do it? Use one of our Soil Blockers to make soil cubes that stand alone.
You can’t rely on traditional potting soil to make soil blocks—it doesn’t have the right consistency and the blocks will fall apart.
Soil Mix Ingredients
The mixture for soil blocks needs to be able to maintain a solid shape when damp.
- Peat moss (or a substitute) is an essential ingredient for holding water and allowing spaces for air. Don’t gasp and turn away. We have peat moss that is sustainably harvested, and we carry a whole line of “coco peat” (coconut fibers) that can replace peat moss.
- Compost for nourishment.
- Vermiculite is sterile and holds water well. Perlite particles are often too large for soil blocks, but can be substituted.
- Rock powder increases air space and adds minerals. We have Gaia Green Glacial Rock Dust and Micronized Azomite.
Tools For Creating the Soil Mix
- Sieve to screen all the soil mixture ingredients through a fine mesh, to have the light texture that germinating seeds need.
- Potting tray where you can measure and dampen the soil mix.
- Respirator to wear while working with fine powders.
Recipes for Soil Mix in Soil Blocks
Soil blocks are better known in Europe than in the U.S., so many of the recipes we have come from Great Britain. Let’s start with the easy one.
Let us do the soil mixing for you. We’ve already formulated an organic soilless seed starting mixture to use in Speedling and Plantel trays, and it works equally well with the Soil Blockers.
This marvelous mixture is called Quickroot and we offer it in 1 cubic foot bags or large 54 cubic foot bags.
The ingredients include coconut coir fiber, vermiculite (no detected asbestos), organic green waste compost, bone meal, and soft rock phosphate.
Peat moss based soil recipes
David Tresemer, author of the Ladbrooke Soil Blocker Booklet Transplants in Soil Blocks, has a favorite recipe:
4 parts peat moss
1 part well-rotted compost
1 handful of ground calcium limestone for every cubic foot of mixture
1 handful of ground basalt rock powder
Thalassa Cruso recommends:
2 parts peat moss
1 part vermiculite
1 part good garden soil (if you have that “chocolate cake” kind of friable soil)
small amount of clay dust as a binder
For any of these recipes or our Quickroot, moisten the soil to a slurry consistency as Tricia demonstrates in our video, then pack the Soil Blocker mechanism and you’ll have your own soil blocks, ready to receive your seeds.
For more information on soil mixtures and soil blocking, get a copy of the Ladbrooke Soil Blocker Booklet Transplants in Soil Blocks.
Are you ready to try soil blocks for your seeds this year?
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