I have been starting seeds for as far back as I can remember. My grandfather had a greenhouse where I received my first introduction and I have been doing it ever since. As with most gardeners, I have used many different seed starting methods from peat pots to newspaper pots to plastic pots and everything in between. This year I heard about a method I had not tried, the Soil Cube, and of course I had to give it a try; and I'm glad I did.
I purchased my Soil Cube from Deeply Grown Organics. There are several companies that sell soil cubes or similar items, but Deeply Grown Organics is a small company, which is where I wanted my money to go. I prefer giving my hard earned cash to a small business man rather than a big company that is probably sourcing their products from overseas.
I will not go into detail describing the Soil Cube. You can find everything you need to know on Deeply Grown Organics product page. My impression of the tool is overwhelmingly positive. It does take a bit of work getting used to it, but once past that, it is great. The product itself is well made. The wood plunger is very sturdy, which it needs to be as it does have to support a good amount of pressure when you are compressing the soil. The chambers are made out of PVC and work very well. The cubes themselves are 2", which is a good size for most home gardeners. In a standard seed starting tray, I can fit 32 soil cubes if I pack them tight. However, due to my current lighting setup, I have found that 24 soil cubes works better. I've made about 120 soil cubes so far and while I have had some fall apart (mainly due to my mistakes or the wrong soil mix), most have held together very well.
I have found that the most important factor in getting a good soil cube is the soil mixture itself. I have used three separate mixtures; two were good, one is a disaster and just crumbles. The first mixture I used was Johnny's 512 Mix (OG) purchased from Johnny's Selected Seeds and worked very well. The mixture was dense enough that the cubes held together well. The second mix I tried was the Germinating Mix from Gardener's Supply. While this is excellent in other applications I have used it in, I did not like it for the soil cube. It was too light and the cube easily broke apart and they continue to break apart. Finally, I decided to make my own mix loosely based on the instructions from Deeply Grown Organics. The jury is still out on how they hold up. This mix formed cubes very well, better than the Johnny's mix, but it is lighter than the Johnny's mix and significantly more dense than the Germinating Mix.
All in all this is a great tool and I highly recommend it to others. While there are many vendors to purchase soil cubes from, I would recommend Clayton Jacobs at Deeply Grown Organics. The transaction went very well and it is a quality product that will hold up for many, many years.