I've noticed most gardeners use the 2" block maker. And, only a few commercial gardeners use the 4" block maker. Maybe it's too heavy, maybe it's too much work, maybe it uses up too much potting soil, or maybe it's too expensive. Some will make their own 4" block maker. But, not me. I have covered why the 4" Ladbrooke block maker is the King. For those that do use the four inch block maker and are curious if it can be potted onto another block, you have arrived at the right place. I call it the fabled 8" soil blocker because nobody makes it, you have to make your own. And, besides, I don't even know of anybody who has ever made one! Why would any body do that? It's true, it brings up a lot of questions, doesn't it? Well, let's take a look at the nursery business. How many sizes of plastic pots do they go through before the final sale? Lots. We're starting to seed in November for summer block sales. We sell mostly soil block six packs in recycled wooden flats. When it's time for larger pots, I reach for the black plastic bags in 1-10 gallon sizes. I use bags because I anticipate the customer throwing them out when they've transplanted their plant. It has way less waste then pots, way cheaper, and way lighter, easier to move, and has a slight square shape, which we all know from soil blocking, saves space. But I'm all about the reduction of plastic pots on my farm. So, one day I decided to build my own 8" soil blocker. Out of new plywood and hardwood dowels and an old metal spring and some short screws came the invention so few will use, so few will need, so few will want. Oh well, I loved it. It worked. It worked just like the 4" block maker. It makes a BIG block. Now, I could transplant long standing plants like blueberries and all of the berry bushes in 8" blocks. I could keep fruit tree saplings around a year or two now with no worries. I could over-winter peppers. I used them for landscaping plants and hedges to roses and flowers, flowers, and lots of blocks of flowers. My next challenge was to provide a way for my customers to cart off their blocks. This block is heavy, like about 5 pounds of wet potting soil, so if it falls, it breaks. Other than that, it can be made out in the nursery and just sit there. With the right blocking mix it was easily moved, but that was also a challenge to find the right blocking mix consistency. And, although I could move it with a wide tined manure fork, I know my customers needed a handle. So, with some left over jute netting, which is similiar to burlap, I sewed a cradle/sling with two handles slightly offset as to not disturb the plant stems. I used some thin hemp twine and a long nail punch and made a very inexpensive reusable sling for easy pickup. Now, it's even better with constant refinement. I build the block right on the sling, or sometimes in four packs with custom slings for blocks of berry bushes or peppers. Much like the wooden flats for 2" six packs, I offer the customer $1.00 off their next plant of the same size if they bring the sling back. Was all this extra work really necessary and worth it? Absolutely! I have a customer base that shop at my garden center because it's different. I keep giving them reasons to support me and spread the word about my offerings and commitment to the environment. With all of this oil talk, I can offer the customer an environmentally alternative to ugly plastic pots, and entice them to come back with the $1.00 "deposit". What are the difficulties in using the "fabled 8" soil block? First, it's heavy. It requires great strength to make a block. Second, it requires a lot of potting soil and a large tub. It has to be deep enough, like twice the size of the depth, which is 8" for the depth as well as 8"x8" on the sides, and enough room for the long charging handles. Third, you have to make them where they will sit for up to 3-6 months or a year. That takes a lot of planning. For my nursery, I use mobile tunnel over landscape fabric to keep them warm in the winter and slide the tunnel off of them for outside summer sales. Fourth, for commercial use, you need to sew up some slings. That is very time consuming to sew up hundreds and in a couple of years, tens of thousands of slings. Fifth, building the blocker so it can withstand repeated use is slightly difficult. I have had to rebuild mine a few times already. Wood and screws cannot keep up with the demand on this machine. I am having one constructed by a metal fabricator starting this year. Email me at email@example.com if you're interested in purchasing one. I am not sure if there will ever be a need for one outside of my unique nursery, but I am here to say that all the principles of soil block gardening are used to create the 8" block and it is well worth it. Here is one design (next paragraph) based on my experience with adobe and rammed earth building. It is so easy to build and easy to use, perhaps this is the idea waiting for discovery.
You'll need: a couple of 2x 8's scraps and some 2 x4 scraps, some 3" wood screws, and a cordless drill. Build a frame with the 2 x8's as long as you want, but preferably the lenth and width of at least a four block maker(21" x21"). Frame the interior of that wood block with cross blocking keeping your 8" square and creating 4 squares. Done. Now, set it on a piece of plywood and water it down really wet. Next, make up some blocking mix with whatever you've got. Refer to my blog on making free blocking mix for ideas, entry for May 11th, part 3. Fill it halfway with a moist layer of mix, but not as moist as regular blocking mix, as you'll want to tamp, or slightly tap the potting soil down with a block of wood. I use a four by four post end cut off and attached to an old wooden handle. Moving on until you reach the halfway point or 4", then build a stack of 2 x4's 3 high(4 1/2") and 4 1/2" inches long. Screw 'em together and you've got your cubic pin. Screw a little block of wood on top in the shape of a handle so you can pull it out later. Water the pin down, too. Lay that in the center and make sure that the cube is flush with the top of your form. Fill with tamping mix around the block and begin tamping and filling until you've reached the top on all four blocks. Now, carefully tap around the outside of the form to release suction. Pull up the form carefully. Note: This is different for every type of wood used. Some woods may catch on the blocking mix and some won't. To be absolutely sure it comes up clean each and every time, do one of these two things: 1.) Sand and paint the inside with Kilz latex primer. Or, 2.) Let your form and cubic pin soak in water for a couple of days in the sunlight and let it get all slimy with algae. I recommend the soaking to get the algae growing because it's natural and easier and slicker. In this case, you must use galvanized 3" wood screws so they won't rust. After the form is pulled off you should have four beautiful blocks. Now, carefully grab the handle of the pin and lift straight up and out. Voila', you're Fabled 8" block is ready to use. Stuff it with your favorite 4" plant and move it in part sun and part shade for a while, and water well in a couple of days with some manure tea. It can sit there virtually all season without the need for transplanting any further, if you fertilize regularly. Transplant late in the season if neccessary, but only in late afternoon. And, if you want to keep this block idea going, make yourself a 14-16" block the same way and Pot On again. You know I will! Blast me email if you've ever tried to Pot On your 4" block. I'd love to hear it, but you know that! The Guru writes again and everyday until the world understands the soil block method. The Guru predicts the wave is coming. The Guru understands the power of relentess pursuit of passion! Au revoir!