Modern Organic Farming Without Soil [Part2]

Click here for part one of this article.


We will start off with the results. Here are some photographs of the result of my experiments. This particular batch of photos are from a fully automated system that I designed for growing my vegetables on the third story terrace, far away form the ground soil. The power required to drive the system is generated from solar panels.

Tomato

Mint

Spinach

Long Beans

Bitter Gourd

After running this system for two years and studying the plant behavior I decided to implement it on individual smaller systems, which might be more practical on balconies and the like. Here are some photos of the result.  I did not try to tame these but let it grow as wild as they pleased, but without soil. Have put down the growth medium used below each photo. The medium select is a neutral medium.

medium: 3/4 inch gravel

medium: machine waste cloth, gravel, cleaning sponge pieces

medium: cocoa peat , 3/4 inch gravel

Working Principle:

The plants use soil to build the root structure and absorb the nutrients required for its growth. The soil also provides support for the plant to stand upright. As the plants grow taller the main root goes deeper and the the branched roots spread further away. The minor roots tend to look for moisture and nutrients. Since too much water can rot the roots the plants prefer moist soil to wet soil.  Moist soil has enough air for the plant roots.

My experiment was based on these main attributes [ and some minor attributes would make this blog boring ] and I formulated a theory. It was my belief that plants are happy when:

• they have just enough moisture
• the right amount of nutrients
• right amount of aeration of the roots
• have a medium where they can spread their roots
• a medium that can support the weight of its steam and leaves

p.s: Most vegetables are happy in a medium that is 12 inches deep.

Selecting Growth Medium:

Based on what I mentioned, I found that the medium should essentially process three major qualities. Firstly it should have the ability to retain moisture and the nutrients we provide externally, secondly it should be able to hold the plant steady and thirdly it should be an inert medium. By inert I mean that it should be neutral by itself. Some of the mediums that I have tested are:

• cloth rags
• gravel
• charcoal
• broken clay tiles
• coco peat [ surface layer ]
• coconut shell
• coconut husk 

Different plants show different growth patterns and varying root structure. For example tomato has a main root area  going down and the rest spreading outward, while in the case of mint the roots run all over the place and so does the plant. So we could safely infer that we can use a shallower and more spread out growing bed for the mint and a deeper smaller surface area growing area for the tomato. So when selecting the pots or growing container choose accordingly.

Building a simple system:

I have designed a construction which uses readily available PVC pipe and joints to make a light weight soil less vegetable garden  for small spaces and balconies. I have done the calculations with 12+ inches of growing bed height.
This will be covered in part 3.