I've read quite a few comments on the net as to why people are reluctant to use so much potting soil to make soil blocks. Reasons like cost, weight, effort, usage, resources, etc., make people doubt their soil block making advantages with insignificant cause. Let's look at this concern.
Isn't the reason for using soil blockers to pack more soil into the seedling space for the roots to stay compact, air pruned, and still provide plenty of space for air, nutriments, and water? Wouldn't that require more potting soil? But, wouldn't that also mean you could have more time before you need to transplant? More green growth while you wait for the right weather, the time to harden off, or even until the harvest of some greens, herbs, or flowers? Isn't it better to have one excellent plant versus a dozen mediocre plants? Well, if you're using up your potting soil resources to make blocks, then you must be doing it right! The 2" block uses the same amount of soil as the 4" round pot! Weren't you going to transplant into the 4" plastic pot anyway? Why risk transplanting? Pot on! Pot on! Pot on! (Sounds like a drum.)
Now the concern over cost of potting soil and your usage. Are you making your own? You can save a bundle by buying peat moss, compost, perlite, and amendments and fertilizers by buying large quantities. Yes, it is more expensive up front, but you may not need to buy them again for years! Or, did you ask your neighbors or friends to split up the bags and spread out the cost? Or, did you buy one bag at a time at your local retail store? Yes, that will eat up any one's budget. Soil blocks demand more potting soil to achieve these wonderful results described in http://www.pottingblocks.com/. We have the Ladbrooke recipe: 4 parts peat moss, 1 part compost, some sand, a handful of lime, a handful of rock powder. PERIOD. Buy a bale of peat moss, make your own compost or worm compost, scoop some sand from your kid's sandbox, borrow a cup of lime from your neighbor and you got yourself approximately 900-1200 2" blocks(depending on the amount of compaction per block). This bale costs me less than $10.00. Folks, that's a penny a block!
Some are complaining of the extra work involved in making the blocks. Wetting the slur, charging the blocker, lifting the heavy maker and releasing it, transporting the trays and watering three times a day, all sounds like a lot of work, doesn't it? It doesn't have to be. Results with soil blocking are amazing if you focus on quality, not quantity. For those who still complain about the extra effort, and there are many of you out there, I have one last parting shot: Give your soil blocker away to someone more ambitious, excited, grateful, resourceful, enthusiastic, energetic, scientific and biologically-minded, environmentally conscious, and, wait for it.....ENLIGHTENED!!! You'll quickly make a best friend and you can go back to the endless train of plastic, sterilizing, storage, Miracle grow addiction, transplanting up and up and up, and more transplant shock than if someone where to move you from your house to a bigger house in Mongolia! It may be bigger, but it wasn't comforting, and you may not recover from your new location no matter how much water and food and hot desert sunshine they give you! Harsh, but forward.