May I inquire first as to why you are not growing right in the regular soil? If you've been told "nothing will grow there", or "the soil's worn out," don't believe it! "SOIL IS SOIL", as Dr. Mittleider often says, and what he is trying to convey is that you can grow great gardens in virtually any soil, anywhere in the world!! Therefore, unless there has been a garden in that spot recently which was diseased, I would suggest you just make level, raised, ridged soil-beds and grow "right in the dirt". By using the balanced mineral nutrients we recommend, your crops will thrive in any soil that is not toxic, covered with water, or diseased.
If for some reason you really must use Grow-Boxes, because you have no ground, but only a driveway, patio, or rocks, then go for it. But DO NOT USE dirt in the Grow-Boxes! And I DO NOT RECOMMEND soil conditioner - especially at $3 per cubic foot - as a viable alternative to sawdust and sand in your Grow-Boxes.
There are at least three reasons not to use commercial soil conditioners:
1) The cost amounts to about $90 per 30' Grow-Box. We are all about making gardening affordable to those who have very little money, and this flies in the face of that philosophy.
2) Usually, soil conditioners have small amounts of a few of the nutrients in them, but you rarely know what is there, and it is not what is needed. So it can actually do more harm than good if it creates an excess of any nutrient.
3) Unless you KNOW the source of the materials used in the soil conditioner – that they are all clean and free of diseases, bugs, and weed seeds - you run the risk of introducing problems from those sources into your garden.
I DO RECOMMEND you look for other clean finely ground-up organic materials that are available free locally, or at very low cost. A few suggestions include coffee hulls, rice hulls, finely chopped coconut husks, Bagass (sugar cane refuse), a really good option is pine needles (yes, these work great, and will not ruin your garden!), and leaves (but avoid scrub oak below 5,000 feet elevation and walnut). If you can find a hammer mill to chop the materials finely, any of the above will work well for you.
Labels: mittleider gardening, poor mans hydroponics