South Australia has a well earned reputation as the driest state on the driest continent on Earth. The place where Denise and I set up camp many years ago has a lovely view over the river valley, but its on the edge of the region known as “The Mallee”, we have an average annual rainfall of approximately 300mm (12 inches) but this year we’ve had barely half of that and the winter rain season is well and truly over. We are in a severe drought and the ongoing forecast is looking grim. My solution in a word – Hydroponics!
Now I’m neither a believer, nor a denier when it comes to climate change. I study and accept the best available scientific evidence, and I have to say that evidence is pointing towards a hotter and dryer future in this part of the world. Though I’m an accountant by profession, I’ve spent the best part of my life “on the land”, as we say, and always involved in agriculture, so I’m familiar with the trials and tribulations of farming.
The idyllic scene on the header of my website is the view that we are fortunate to see every day from our property, which overlooks the River Murray, the precious lifeline upon which our lifestyle depends. It is a constant reminder of how fragile we are in this drought prone land and how easily we could be wiped out by a few degrees of change in climatic conditions.
One of our daughters is an agricultural scientist specializing in soil and water management and recently we have collaborated in establishing a small research facility to test different ways of coping with the likelihood of longer and harder droughts affecting agriculture in our already arid land, hence “Aridag”.
The Hydroponic Accountant
As I’ve already mentioned, I’m an accountant by training and If nothing else it has taught me to look for the best economic solutions to any business issue. One that I’ve long had an interest in is the use of hydroponic technology to supplement fodder supply in drought conditions. Consequently I’ve recently set up a trial system producing barley sprouts and I’d like to take you through the process.
A lot of the published material, both in books and on line, tend to give the impression that growing hydroponic fodder crops, e.g. barley, is easy. All you need is a tray, some seed, nutrient solution, mix it all together and presto; in a week or two you’re ready to feed a lovely mat of greenfeed to the livestock.
I’m afraid it’s just not that simple. Mind you, old cynic that I am, I never believed it would be, and needless to say it isn’t! In my initial trials did things according to the book with rather mixed results. The first tray wasn’t bad, much slower than they promised but good cover. The next one was terrible. Sparse germination, uneven growth, so I abandoned it and went back to basic science.
Out came the text books on plant biology, plus a couple of good ones specifically on hydroponics, by a bloke named Joe Romer, who I’ll be quoting as I go along. First up my old university text book on plant biology by Kingsley Stern (Who I’ll also be quoting in this essay. Back to writing essays I fear, but I’ll try to make it interesting!
Let’s start with the basics of plant growth in normal soil based conditions. Which after all is what I’m trying to emulate and hopefully improve on.
INITIAL ROOT DEVELOPMENT
What is a seed? Well Stern says it’s a “Mature ovule containing an embryo in a protective seed coat. (Stern: Plant Biology p137) In order to germinate it needs an interplay of factors, both internal and environmental. These include access to water and oxygen. Initially, in the case of barley and similar crops, they need up to 24 hours of soaking in order to soften the seed coat. Once soaked and set out in the seed tray, they need to be periodically exposed to wetting with nutrient solution, but also aired to provide oxygen, which is essential for root growth.
Now I’m using what is called “Nutrient Film Technique” hereafter called NFT. Which is the most common method of growing hydroponic fodder crops. I shall describe it in detail as I go along. The devil is, as ever, in the details. Of the various online sources I will refer to one by David Capocci, an American (We can’t blame him for that of course) from a place called “Paca Pride” in Washington State. He has a great web site though he does tend to exaggerate (Well don’t they all) but excellent descriptions of the basic process and infrastructure needed.
GREEN SHOOT DEVELOPMENT
Once the roots are established and begin extracting nutrients from the water, green shoots should begin to emerge within a couple of days. This went pretty much according to plan in my system. So far so good. But this brings us to the key players in the plant development cycle, and the inevitable problems that raised their ugly little heads.
To begin with let’s see the light, literally. As we know, the process by which plants derive the energy to grow is photosynthesis, which requires light. (Stern pp 164-165) The phenomenal rates of growth claimed by the professional growers “Seed to feed in 7 days” for crops like barley, are only possible under the most stringently controlled conditions. For light this means either providing artificial light at night, where the setup is out of doors, or in the case of fully enclosed, climate controlled buildings, 24/7. I may or may not go down that road in time, but right now my system is open air with night lighting to come. Without night lighting at all my growth rate are nearly double the ideal.
This raises some additional problems that tend to be glossed over in the promotional literature. Surprise, surprise! My first two trays were total failures as a result of these issues. To begin with I spread the seed, as recommended, approximately ½ inch (12mm) deep in the tray. Consequently much of it (I estimate up to 2/3) failed to germinate and accumulated as a soggy mass in the bottom of the tray. After about 12 to 14 days it rotted and ruined the whole batch. Lessons learned from that experience were firstly to halve the amount of seed and secondly to do whatever it takes to speed up the process. Seven or eight days turnaround is more than just a marketing line. The fact is that if it takes too much longer it ends up on the compost heap.
My next step is to add night time lighting, plus an appropriate aeration system for the root mat to help prevent fungus, fermentation etc from setting in. I must add that I have now reached the stage with my initial small experimental setup of being able to feed out a tray of good quality greenfeed every two or three days. Do they eat it? You’d better believe it. It’s just a matter of put it down and jump back to avoid being trampled in the rush. So I’m
now sufficiently encouraged to start working on a fixture that will incorporate lighting, aeration pumps and timers to help automate it, to reduce the labour involved and get closer to the 7 to 8 day timeline.
ROOT AERATION:
One point emphasized by Australian hydroponics pioneer Joe Romer in his book “Hydroponic Crop Production”, is that adequate oxygen supply to the roots of growing plants is CRITICAL. (Romer; p8) In nutrient flow technique (NFT) such as I’m using, the most popular method seems to be aeration of the nutrient solution in its holding tank. This is done by using an external air pump connected to a so-called “Air Stone” in the bottom of the tank, as commonly used in aquariums. This should work well in the flood and drain version of the NFT system, where the trays are irrigated by a timer which switches the pumps on for around 10 minutes every 3 or 4 hours. With adequate drainage holes the solution passes through the crop roots and is either collected and recycled, or allowed to run to ground (Preferably to a part of your external garden). Depending on whether you’re using a recycling or non-recycling system.
In my next post I’ll cover LIGHTING:This is the most exciting part of the operation for me (And my grandson Ben) Because it is front line science with huge potential, using LED technology, which is expanding faster than I can keep up with. But I’m giving it my best shot!
Meanwhile here are a couple of photos of my early effort. It’s primitive at this stage but as you can see the animals certainly go for the end result!
Follow my progress as I implement a hydroponic fodder program utilizing LED lighting
As I mentioned in my previous post, the most important advance in recent years has been the rapid development of lighting systems for hydroponics. In particular the remarkable advances in LED lighting. Electronics has long been a hobby of mine and over the past decade or so I’ve witnessed the development of LEDs (Light Emitting Diodes) from little red indicators to full scale illumination devices for home, industrial and motor vehicle uses.
My limited experimenting to date suggests that artificial lighting, whether to extend daylight hours, or to grow barley shoots inside a shed is not worth the trouble and added expense. My best results have been achieved in shadehouse conditions during summer daylight hours. Consequently I am expanding my shadehouse to increase production next summer. In our climate the need for added greenfeed is greatest in the dry season anyway. I still intend to experiment with LED lighting to grow some cherry tomatoes (My favourites) which have quite different growing requirements from barley sprouts. Edit Search
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