Soil Blocking Workshop and Planting Seeds

Seedlings started in plastic divided containers will look like this.

On March 13th, students and community members gathered in the Anthropology building greenhouse at U of T to learn how to soil block with Bonnie Scott, and to plant seeds for this year’s growing season.

Soil blocking is a technique for growing seedlings without the use of plastic pots.

Soil blocking, in contrast, looks like this:

taken at the soil blocking workshop in the Anthropology Building Greenhouse on March 13
Taken at the soil blocking workshop in the Anthropology Building Greenhouse on March 13

Blocks are made up of a combination of soil, sand and nutrients, Bonnie explained that this method of germination produces healthier seedlings because roots are able to spread out and don’t become bound and tangled in the pot, which allows for a more successful transplanting of the seedling into the ground. For this workshop, Bonnie used Eliot Coleman’s soil blocking recipe, which can be found here, there is also a useful series of videos on the internet for reference. We used Coleman’s recipe as a guide, though another great aspect is that soil blocking mixes are customizable depending on the resources you may have. For our mix, we used less then half the recommended amount of sand because the type we had was really fine. Also, lime will only have to be added if you are using peat, to balance its acidic pH. There are lots of resources available on the internet to guide you through soil blocking mixes. 

IMG_1908
Recipe for soil blocking mixture. This mixture is important as it has to have nutrients and be compact enough to hold the shape of the block.

Soil blocking requires the use of a small soil compactor, as shown in the picture. Soil is packed into the mechanism and is extracted with a small hole in the top of the soil block where seeds can be planted. Soil is then pinched closed, to cover the seeds. Larger seeds may need to be pushed down slightly. Make sure to place soil blocks onto a container to hold excess water.

Bonnie putting the soil mix into the soil blocker
Bonnie putting the soil mix into the soil blocker

Soil blocking is a great way to seed in a cost-effective and plastic free way. Soil blockers can also be shared among community gardens or urban agriculture organizations in the city, making it a truly sustainable technique for planting.

Students plant seeds. Seeds are labeled with the name of the variety of plant and the date they were planted on wood stir sticks.
Students plant seeds. Seeds are labeled with the name of the variety of plant and the date they were planted on wood stir sticks.

Students returned after the work shop to plant more seeds. Between the two work days we planted a variety of tomatoes, herbs, squash, cucumbers, hot and sweet peppers, greens such as swiss shard and kale. Other veggies and herbs will be sown directly into the gardens

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