Maximum Yield USA 2011 August | Page 22

SIMON says Hey, I was wondering if organics, such as guanos, can be used for hydroponics, and is guano enough for a full schedule for the veg and bloom stages? The awkward partnership of organics and hydroponics intersects once again! There is a lot of debate about using organics in hydroponics. While it is feasible in theory, it is very difficult to make it function in the real world. In the successes I have seen myself, they are generally based on compost-amended soilless mixes; if they are water systems, the crops are low nutrient requiring plants such as lettuce and some herbs. Most of the problems associated with organics and hydroponics are related to the level of soluble nutrients. Nitrogen and calcium availability would be two of the biggest problems. Organic products, unless digested through enzymatic action, fermentation or chemical extraction are generally only partially soluble, if at all. Powdered guanos would be mostly insoluble, although they could be suspended in solution if agitated. However, just because something is suspended doesn’t mean that plants will be able to access it. In most cases the best way to digest organic material is through microbial action. In hydroponics systems there would be very low levels of microbial action and it’s unlikely that you could get enough activity to break down the guanos into usable forms. 20 Maximum Yield USA | August 2011 There are a range of guanos available in the market. Most are from bats and birds and they all have various nutritional ranges due to the variety of food sources consumed by the animals. Guanos can be a great way to get a high power organic option into your garden and nutritionally you are right that guanos could be a very strong nutrient foundation. Outdoors, in true soils, where guanos can break down over a season in the presence of vast amounts and diversity of microbes, it’s possible they could provide a stand alone nutrient for your garden. Indoors, guanos will require a bit more preparation in order to give the results you want. If you are keen to use guanos, the best idea would be to choose a soilless mix with a high level of biological activity. Add as many microbes as possible with inputs like worm castings, weekly doses of an aerated compost tea and microbial stimulants like kelp and humic acid. Mix the guanos into your potting mix prior to planting and let the microbes feed themselves and in turn your medium and plants. The organic material would break down over a few months and provide a natural slow release nutrient supply for your plants. To fill the gaps and ensure the best crop possible I would consider having a fermented liquid organic ready, just in case the release curve doesn’t keep up with your plants. Keep thinking organically and as always I recommend experimenting; every situation is different and you won’t know unless you try. MY Do you have a question for Simon? Send it to [email protected] with the words “Simon Says” in the subject line, and your answer will be printed in an upcoming edition.