How many times have you tried to start seeds only to have the seedlings wither and die? Or maybe the seeds didn’t even germinate! What if they got root bound in their little pots and didn’t thrive?
Seed starting can seem so complicated! There are so many variables; it can feel overwhelming to a new gardener. Seed starting with soil blocks simplifies the process and takes the stress out of starting seeds.
What Are Soil Blocks?
Soil blocks are exactly what they sound like; compressed blocks of soil used for indoor seed starting. They have a small divot in the top to place the seed in. The blocks serve as pot and soil to grow your garden seedlings. Sometimes they’re called seed blocks or soil cubes but really it is all pretty much the same thing.
Making soil blocks is easy if you have a Soil Blocker tool. The soil blocker tool was developed by Eliot Coleman, author of The New Organic Grower. There are multiple sizes ranging from 3/4″ up to 4″. There are all kinds of accessories to adjust hole size and make more at a time but, I have found that the 2″ blocker with 4 cells works best for general purpose seed starting.
Why Use Soil Blocks?
Seed starting with soil blocks eliminates some of the variables that lead to failure and make the seed starting process a bit less complicated.
Seed blocks reduce the chance that seedlings can become root bound and provide better oxygenation of the root system. Thanks to those two factors, the chances of transplant shock are also greatly reduced.
I love that soil blocks eliminate the pot and much of the trash that goes along with starting seeds. I used to hate throwing away all the little containers, usually repurposed, that only lasted one season.
How to Make Soil Blocks
For seed starting with soil blocks, Eliot Coleman recommends a particular soil mix for the blocks in order to get the maximum nutrients to the seedlings. You can find that recipe here. You can use his prescribed mix or a store-bought seed starting mix.
I use the 2″ seed blocker that creates 4 blocks at a time.
Mix your seed starting medium with enough water that it holds together when you squeeze a handful but it doesn’t stream out of your hand.
Press the soil blocking tool into the soil/medium, twisting it and pushing it into the soil. You want to fill all of the blocks and compress them.
Set the soil blocker into your seed starting tray and carefully squeeze the handle. The soil blocks will be pushed out of the blocking tool and into your tray.
Place a seed in the dimple on the top of the block. Don’t forget to label what you sow! I like to put all the same variety in a single row and just label the row.
Cover the tray with a clear dome lid. This holds in heat and moisture but allows light through. Many seed require light to germinate.
If needed, set the tray on a heat mat. In my climate, I definitely need heat for peppers and tomatoes to germinate. I find that most other seeds don’t require it.
Check every few days for sprouting and that the cubes remain damp. If they need to water, use a fine sprayer or water from underneath. Otherwise, you may wash the seeds right out of the block.
Once the seeds germinate, they need to be moved off the heat. Remove the cover and make sure they are under a low-hanging grow light. If the light is too far from the seedlings, they will get leggy reaching for the light.
Be sure to watch the video for a complete discussion on seed starting with soil blocks.
Want More Gardening Ideas?
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