Using a Soil Block Maker for growing your own seedlings is a quick, low environmental impact method for starting your own seedlings.
I’ve been growing my own seedlings for about 10 years now. I’m pretty set in my ways and the methods I use. So set in fact that I even made a video course on my method (Learn more here).
I use the plastic 4-cell packs to start my seeds. I just like it. However, I have several gardening friends that I made while in the master gardener program that are using a soil block maker to start their seedlings. I’ve always been curious about how they work and this year I had a chance to borrow a soil block maker from a friend and I used it a few times to start some seedlings.
So I thought I’d give you a little review and let you know how they worked out. Please note, that this is NOT a sponsored post, no company asked me to do this review. Included in this post are a few affiliate links if you are interested in buying a soil block maker you can. I didn’t choose one particular company so you should have a good variety to choose from.
Using a Soil Block Maker
So the idea behind a soil block maker is you use this little gadget to compress a big chunk of seed starting mix into a block.
You then plant your seeds in the top of the block and the roots grow down into the block of soil.
Yes, you could probably come up with a way to do this yourself, but these things are pretty convenient.
Once you have packed the soil into the block maker it has a handle that you press down on that pushes the blocks out of the maker.
The handle also makes a handy little depression on the top of the soil block where you plant the seed.
Advantages of Using a Soil Block Maker
No Plastic Waste
I think the biggest advantage of using a soil block maker is you’re not using a container and then there isn’t any plastic waste. Even though I reuse my plastic cell packs for several years, I still end up throwing them out after 5 or so seasons. With a soil block, there is no waste and you also don’t have any worries about BDP or other chemicals getting into your seedlings.
Better Root Growth
Because there is no container you have fewer issues with plants becoming root bound in the container. This is a problem I often have, especially if we have bad weather and I end up putting off transplanting. Rootbound plants do not transplant as well and can be set back weeks in their progress when they are out in the garden.
The roots will also be healthier because you are less likely to have too much moisture around the roots like you would if they were in a poorly drained container. Too much moisture around the roots can cause a bunch of different problems with your seedlings.
Lots of size options
Soil block makers come in 3 or 4 different sizes, giving you lots of options for different plant sizes. Using larger blocks will allow you to keep your seedlings growing indoors longer, giving you strong, larger healthy starts.
Forces bottom watering
When you are using a soil block maker you have to water the blocks from the bottom! You put the blocks in a tray and then fill the bottom of the tray with water when needed. I’m a huge fan of bottom watering of seedlings. Seedlings seem to do much better when you water them from the bottom, this forces the roots to go deep in the soil to look for water, instead of staying closer to the surface like they would if you water from the top.
Disadvantages of using a soil block maker
The soil Dries out quicker
You do have to watch soil blocks a little closer in the water department. Because there is not a container around them the soil can dry out quicker.
Harder to move around
Your soil blocks have to stay in a big tray. That makes things a little harder to deal with during the growing process. If you have some plants in the tray doing better than others they might need to be moved to a different lighting station. That’s pretty hard to do when they are all packed together in one tray.
I also used the larger blocks to grow some lettuce. The roots of the lettuce plants never really filled the whole block. When the transplanting time came, getting those plants out of the tray was a little awkward.
They are a little pricey
At around $30 each using a soil block maker to start your seedlings can be a little pricey up front. Over the long run, they will pay for themselves. But there is a much larger upfront commitment.
My Overall Feelings
Overall I was pretty happy with my first time using a soil block maker. They were very easy to use and they grew good strong healthy starts. I’m sure a few of the issues I had with them would have been resolved had I had smaller soil block makers. The one I used was the second largest. I think one size smaller would have been better for the small plants I grew. It also would have saved the seedling mix.
These guys will be going on my Christmas list this year. I look forward to including them as part of my seed starting program. I think they will be particularly handy for large numbers of flower starts. They will also be great for things like lettuce where. With lettuce, I like to have a bunch of smaller starts to set ours after only 4 weeks. I don’t think I would use them for larger starts like tomatoes, peppers, or broccoli, where the plants are in the containers longer and grow much larger.
Here’s a list of several different soil block makers for you to check out. (be aware that these are affiliate links so I will earn a small Amazon commission if you buy):
Genuine Ladbrooke Mini 4 Soil Blocker
5-PC. “BASIC GROWER” SOIL BLOCKING SET: Ladbrook
Anyway, these links will give you a few ideas on where to find this great gardening tool!
Will Old Seeds Still Grow? Sprouting Test
I bought a soil block maker last year. I think the same size you picture in the post. My blocks completely came apart, so I was very disappointed. I would like this to work, so trying again this year.
I’ve only used them twice now, but the key to making it work is packing a lot of soil in the blocks. Make sure they are full and packed tight. Also, you might try putting them in a tray (with holes in the bottom) where they fit perfectly and then placing that tray inside a larger one and then watering from the bottom of the larger tray and allowing the water to soak up into the soil of the smaller tray. That way there isn’t soil “interacting” directly with the soil in the blocks.
You need to put more water when mixing up your soil, grab a handful if it clumps together good it is right. you want a thick brownie texture. Experiment. Look up Eliot Colemans mixture for plane starting, it is a good mix.