Make Your Own 4-Inch Soil Block Maker

Gardeness, Renee and Caffeinated Mom, welcome to the blog!


I've been intrigued by the idea of soil blocks ever since I read Eliot Coleman's New Organic Grower a few years ago. Last month, I finally got around to purchasing 3/4-inch and 2-inch soil block makers from Johnny's Selected Seeds. I also wanted, but did not purchase, the 4-inch blocker simply because it was too expensive for my gardening budget. The 4-inch block is great for larger starts like tomatoes, peppers, cucumbers, melons, and eggplant and for late transplanting. But I couldn't justify spending the $119 its costs. As a result, I thought I'd try to come up with a homemade solution.

I have to thank my son for this bit of inspiration. I came across his old set of nesting boxes in the basement a few months ago. They were made of sturdy wood and coincidentally enough, held boxes that measured 2 and 4-inches on each side. I also grabbed the 3.6-inch box that fits snugly inside the 4-inch box.


I started by breaking the 3.6-box into its 5 sides. I took 2 of the squares and drilled at the center of each a hole big enough to fit around the diameter of a 4-inch bolt. I then drilled the same-size hole at the center of the bottom of the 2-inch box.


To create the 2-inch soil block insert (which is used to pot-on transplants started in 2-inch soil blocks), I slid the 2-inch box bottom-side down onto a 4-inch bolt. Then I slid one of the squares on top of the box and secured the pieces firmly with a nut. To create the direct-seeding dibble insert, I slid a couple of nuts onto the bolt, followed by the other square and then secured with another nut.


Finally, I cut a hole into the center of the bottom of the 4-inch box big enough to fit around the nut.


To make the soil block, you slide an insert into the 4-inch box and fill firmly with the soil mix.

To release the soil block, push down on the bolt to compress the block and lift the box.

I will probably apply a non-toxic water sealant to the inside of the box and inserts to keep them from warping. Hopefully, I will be able to test my homemade 4-inch soil block maker soon. So what do you think? Will it work?