Sunday, August 24, 2008

Using Soil Blocks in Hydroponics--Part 1 of 3

Soil blocks make the perfect growing medium for a simple hydroponic unit. Suprised? Isn't hydroponics supposed to be soil-less and water based? They can be, but there is a big misconception that hydroponics have to be that way. Hydroponics can be any way you like. Not that you'll hear that from the hydroponic dealers who all want to sell you something better. Soil blocks in a hydroponic setup has many advantages over a traditional hydroponic kit. First, soil is a forgiving growing medium, which is to say, you can screw up with fertililzers or forget to water and your plants are not going to die. Second, using soil blocks in hydroponics is easy to use, not like the complicated hydroponic systems which need pumps, timers, sterilizing, meters, monitoring, costly fertilizers, and water purification and ph adjustments. This is too much science and not enough enjoyment. Third, making soil blocks from your own potting soil is a lot cheaper than buying rockwool cubes for every plant you want to grow. We are going to lead you down the path of least resistance; soil block hydroponics. Of course, you should have a set of soil blockers. I call a set as follows, a Micro 20 3/4", a Mini 4 2", and a Maxi 1 4". You can view these blockers here at This is a one time investment, unlike rockwool cubes or even coco cubes. When the blocks are done, they go in the compost pile with no little wrapper. With rockwool, you're back to the store for more. With soil blocks, you make your blocking mix up or purchase some potting soil and you have unlimited amount of blocks for pennies a piece. Fertilizers can be made at home with compost teas, worm teas, and manure teas for pennies a gallon. Containers for soil blocks can be made from reusable plastic bins or rubbermaid bins or barrels or even wood trays lined with greenhouse plastic. A step up with modual container size systems would be the use of high grade black plastic nursery grow bags from sizes down to a quart all the way to 30 and 50 gallons. (email for prices and details)The rest of the bags are filled with a number of inexpensive growing mediums like inert pumice stones, coco/coir chips, clay pellets, Vegan compost, or even shredded straw. Seriously consider using numerous local byproducts of farms, like walnut shells, plum pits, or moss found in a forest floors or the old man's beard moss growing from fir tree limbs. These are safe, environmentally responsible growing mediums which are ecologically harvested and minimally produced. Nature provides if we look around.
Now, the issue of watering can be as varied as the person who's doing the growing. There's the manual top watering with fertigation, or water plus fertilizer in a diluted form. There's manual bottom watering, ebb and flow, wick watering, or wicking, and then water basins, pumps and timers for the automated setup. All these hydroponic setups can cost little to nothing, and allow the beginners of hydroponics to get their feet wet and still outgrow the professionals. How? Simply by the miraculous power of soil. Yep, soil is a miracle substance that just water and fertilizers do not have alone. You can have one without the other, but make mine with soil. I like the billions of microscopic biological creatures, called the Soil Food Web, to assist my plants whether I'm growing hydroponically or in the farm field. For every problem that comes up with most hydroponic growers, something has to be bought and applied and fixed in order to get a crop. With soil block hydroponics, if a problem comes up, you have the power of natural based elements like compost teas, wildcrafted or garden herb teas, kitchen ingredients like molasses, milk, eggshells, and spices like cinnamon, cayenne pepper, and dish soap for remedial aids. These cost nothing and work with soil and effectively balance out your little biological imbalances like bugs, pests, molds, fungus, etc. Soil is like the fulcrum point in hydroponic gardening where you can always get balanced with something on one end or the other, like air, water, nutrients, biology, light and temperature. With just a water based hydroponic system, EVERYTHING must be precise or you'll end up with some pretty sad plants. I prefer the forgiving and learnable art of soil and water hydroponics. Stay tuned for part 2 and I'll teach you how. But first, take a look at the soil block web site of choice:


  1. Thanks for the post, we will post your Hydroponic setups article. I will post for our customers to see your articles on your blog Hydroponic setups

  2. Thanks for the post, we will post your "do it yourself hydroponics" article. I will post for our customers to see your articles on your blog do it yourself hydroponics

  3. Your page states this is a 3 part series, but I can only find the first page. Did you actually post the rest of the series, or did you not get around to it? Have you experimented with soil blocks in a flood & drain system? I very much like the idea of such a setup for transplant production and soil hydroponics between transplant runs. I have flood & drain components already, and would only need the soil blockers. My big question is whether the blocks will hold up to the water or whether they'll crumble. when soaked really well. Any feedback would be greatly appreciated.

    1. Hi Bryan,
      We've never gotten around to finishing it, but we have had great results with soil blocks in hydroponics. We got really busy selling the soil blockers and started skipping all the written articles! But, it is important to make a block that holds up to the flood and drain system. That is key and the answer is peat moss, worm castings, plug-grade perlite, rock dusts, colloidal phosphate, dolomite lime, and greensand. This combo in correct proportions will hold up under any watering regime, as the rock minerals act as a concrete-like binder to the peat moss and the worm castings act as a moistening glue. Trial and error will yield the best block for your particular system, but the basic recipe can be found at Please stick with this recipe as we have proven it out. Coir or coco peat does not hold together well enough and will crumble. The point here is that the peat moss and worm castings don't have to be overly compact to hold together even against constant fluxuating water regimes. Whereas coco peat, vermiculite, large chunks of perlite and/or rice hulls have to be so compacted to stick together that their ceases to be any air holes left for breathing plant roots. Any further information you should contact my email at I hope this helps.

    2. According to me, a soil block is a prevent of increasing method that has been gently compacted and formed by a form. There are very nicely described about using soil blocks in Hydroponics. The article is very informative.
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