Many commercial vegetable farmers start their seeds in soil blocks. These are exactly what they sound like: blocks of soil held together with the right amount of moisture. The purpose of soil blocks as opposed to pots, cell trays, or cell packs is to allow the roots of young plants to “air prune.” When the roots grow large enough to start enveloping the soil block, they will slow their growth as they come into contact with the air. This is beneficial because it avoids plants becoming rootbound, or suffering from crowded roots with cause stress and can stunt plant growth. Use the recipe below to create your own soil blocks at home
- 20 lbs soil mix (your choice)
- 2 envelopes unflavored gelatin or agar agar flakes for a vegan alternative
- 1 quart water
- 5 gal bucket
- a saucepan
- a clean 6 oz. can with both ends removed (save one round end!)
- an empty seed flat
Boil the water in the saucepan, remove from heat and stir in gelatin until dissolved. Cool. Meanwhile, put the soil mix into the bucket. Add enough of the gelatin to the soil to that a clod forms when you squeeze a handful of soil. Fill 6 oz. can with your gelatinous soil, press with recycled can end, and push into seed flat. Repeat until you’ve emptied your bucket. Allow blocks to set 1-2 hours before planting seeds.
Organic Growers School is a non-profit organization providing organic education since 1993. Our mission is to inspire, educate, and support people in our region to farm, garden, and live organically.