Many newcomers to the world of gardening mistakenly believe that the difference between hydroponics and organics simply lies in the bottles they choose to buy. The organic grower buys the bottle with the word “organic” on it and the hydro grower buys the “hydro” stuff. It’s a tempting over-simplification but, in reality, the difference in both practical approach and growing philosophy goes a lot deeper.

Hydroponic nutrients contain a precise balance of elements needed by your plants to grow and bloom. I like to use the analogy of an astronaut’s health-shake—one of those mega-nourishing drinks that contains everything they need to go on space walks, play cards, and whatever else astronauts do all day. Liquid hydroponic nutrients are derived from mineral salts that have been mined from the earth and then chemically synthesized using fossil fuels to create inorganic fertilizers. These fertilizers are in a ionic form that plant roots can access and assimilate immediately.

Organic nutrients … well, we should stop right there. It’s more accurate to speak of organic inputs, rather than nutrients. That’s because organic growers rely on bacteria and microbes to mineralize or ‘break down’ these complex organic substances into ionic (plant accessible) nutrients. These bacteria and microbes are present in healthy soil. They can also be brewed at home in compost tea.

Organic inputs are largely naturally-occurring unrefined materials that will fertilize plants through the action of microbial mineralization. These organic fertilizers include sugar beet extracts, worm castings, guano, animal manures, compost, blood meal, bone meal, fish products (meal/emulsion/hydrolysate), alfalfa meal, feather meal, seaweed, unrefined naturally occurring minerals (glacial rock dust, soft rock phosphate, Epsom salts) and many, many more. Manufacturing liquid organic nutrients is a complex process that involves the selection of key ingredients that will stay stable and soluble.

If you’re new to the concept of ‘microbial mineralization’ try thinking of the earth as one giant compost heap. This amazing hidden world of microbiology does the work of cycling this organic matter back into a form that plants can use. It’s the reason why the Amazon rainforest thrives without any additional fertilizer!

Hydroponics is a preferred method of cultivation, especially commercially, because it affords the grower increased control over the nutrition available to the plant. When factors such as nutrient pH, strength and temperature are well managed the results can be astonishing—huge production is possible from the smallest of spaces.

Organic growers, on the other hand, will counter that their chosen method is more sustainable as it does not rely on large quantities of fossil fuel energy required to purify this finite mineral resource. Exponents of hydroponics often counter this with the fact that recirculating hydroponic growing systems use up to 90% less fresh water than conventional growing methods!

Language often holds in itself more wisdom than the wisest of those that use it. The word “hydroponics” literally means “water working” – the water does the work of carrying the nutrients to the roots and the job is done. In organic, soil based growing, or ‘terraponics’ growers focus on ‘feeding the soil’ rather than feeding the plant. The soil, or rather, the microbiology within it, does the ‘work’ of getting water and nutrients to the roots, usually in some mutualistic exchange that benefits all concerned.

Exponents of bioponics and aquaponics claim they have successfully merged organics with hydroponics and combined the benefits of both. When you consider the very different approaches in terms of plant nutrition, this is no mean feet! Simply adding organically derived liquid inputs to a hydroponics system is not going to cut it. (We’ve seen many growers try and fail!) There are many reasons for this but the primary cause is the absence of the microbiology needed to breakdown the organic inputs into plant-accessible form. Other problems include organic nutrient solutions going ‘bad’ and clogged drippers. Most organic nutrient solutions are unable to stay stable in a hydroponic reservoir for more than 24-48 hours, which often leads to a smelly sludgy soup, the growth of bio-films and clogged pipe work.

There are a number of exciting new technologies that may help us to combine hydro with organics. William Texier from General Hydroponics Europe has developed a concept he calls ‘BioPonics’. Four years of research and development resulted in a the BioSevia Grow and Bloom nutrients, the ingredients of which are soluble, derived from approved organic sources and proven to remain stable in a hydroponic reservoir. It is a complex combination of already dissolved ions from organic origin, and larger organic molecules that will decompose rapidly (in a couple of days), to allow continuous nutrition availability from start to finish. This fast decomposition process is activated and sustained by the introduction of beneficial microorganisms contained within a ‘biofilter’, in which bacteria and fungi (particularly Trichoderma harzianum) feed on the carbon part of organic molecules and release the ions attached to them, which is exactly what plants are looking for.

For more information on the development of this ‘Bioponic’ Nutrient – see the article in Urban Garden Magazine Issue 6 (08/09 – 2009) My Quest for “Bioponics”.

This year we will also see new lines of nutrients coming onto the market that claim to deliver the power of hydroponics in an organic boxing glove! Here at Urban Garden HQ, we look forward to testing the claims of the emerging ‘organic hydroponic nutrients’ and sharing our findings with you in 2011!