Soil Blocking 101
Soil blocking is a great way to start seeds because it is so sustainable. It’s also much easier to transplant seedlings from convenient little blocks without having to pull or squish them out of plastic squares. Learn the basics of soil blocking here so that this season you can easily start seeds without the mess of plastic trays.
Soil blocking is simply a method of using a special tool to create self-contained blocks of soil that you can start your seeds in. The key is to find the size soil blocker that you like and a seed-starting soil mix that is equal parts nutritious and light, but also holds shape. Don’t worry, we have this for you!
With soil blocking, you will need:
- A soil blocker tool
- A tray for the soil blocks to go in
- Seed starting soil
You can buy a soil blocker online anywhere from Amazon to Gardener’s Supply. There is a variation in the size of the block, and the shape of the seed impression. When you use your soil-blocking tool, you’ll scoop up some soil, then press your blocker down by squeezing the handles together. It will create four soil blocks and then an indentation on the top for the seeds to go in. That indentation can be either a circle or a square. The size of your blocks can range from ½” to 2” depending on your needs.
The most basic is about 2” in size with four blocks across and a circular indentation – great for any seed starting.
The key to great soil for soil blocking will be getting a good loamy consistency, which will also depend on the amount of water you add. You’ll need to get your hands dirty and test this out. You want sticky, but not muddy soil.
Here is a recipe that we have had success with:
- ½ bag potting soil (about 5 lbs)
- 8oz perlite
- 1/2 cup of blood meal
- 1/2 cup bone meal
- 8 oz coconut coir
- 1 lb compost
- Enough water to make the soil sort of sticky, but not muddy
This will give you quite a bit of soil, so save what is left for the rest of the season or amend your beds with it.
To water your soil blocks, we recommend you water into the side of the tray, so the bottoms soak up water. Misting on top is great as well. Keep your soil moist until germination, and then adjust.
PRO TIP: A light dusting of cinnamon on your seedlings will prevent any fungus from growing and a light dusting of vermiculite will keep water in. Very light dusting of each is great – but neither are “musts”.