One of the common questions often heard at CropKing is the optimal environment for hydroponic fodder production. To begin to address this topic, one of the first catch phrases that come to mind is “controlled germination.” This term fits well with hydroponic fodder production because we are only concerned with the first seven to fourteen days of growth. These plants are relying very little on the sun to provide the energy they need to develop, and more on their “food” stores within the seed. This “food” or endosperm inside of the seed is most often in the form of starch. Starch can be converted to a more easily digested form for our livestock to consume through the process of germination. These facts alone can certainly influence the way we approach our environmental control.
Like any other crop, the grain seeds we use in a hydroponic fodder system germinate best in high humidity environments. In vegetable crops we often use a humidity dome or a propagation greenhouse for the first couple of days before emergence to keep our relative humidity at 90% or above. This is where our fodder starts to stray from normal germination conditions. Although having humidity levels close to this 90% range may speed up germination, it also speeds up the growth of many molds that can be extremely detrimental to production as well as animal health. It is for this reason we look for a humidity range that encourages germination to a satisfactory rate but does not aid in the proliferation of these molds. Having precise control of these humidity levels is thus of paramount importance.
|CropKing's research fodder building|
Having solid control of this humidity can be more challenging task in some buildings more than others. Here at CropKing I am fortunate to have a 30’x40’ steel structure that is heavily insulated with a spray foam material with a high R-Value. This means that my heat and humidity are well conserved and it is generally not difficult to keep my relative humidity above the minimum of 60%. It is rare for the relative humidity to drop to a level unacceptable for germination when at least one of my fodder units is up and running. Dehumidification though can definitely become a necessity. There are many equipment options when looking into dehumidification such as “heat pumps” to the more cost effective “at-home” dehumidifier made for keeping your basement less muggy. Heaters can also go a long way to reducing ambient humidity, but regardless of how you do it; the humidity must be kept below 80%.
If these facts are kept in mind while deciding where to put your fodder rack some basic questions arise; Such as, how much will it cost me to heat/ cool this structure and what will my dehumidification needs be? When answering these questions it becomes apparent that it is much more cost effective to run this type of system in an enclosed and heavily insulated structure such as my steel building. It seems that it is becoming more common for people to start growing in
structures such as greenhouses or poly-huts. The main benefit to growing anything in a greenhouse structure is the accumulation of “free” sun energy, which as stated before is not the main concern
|CropKing's research greenhouse|
while producing fodder. So are there actually any benefits of growing in a Greenhouse versus an enclosed structure? With this question in mind I ran a couple of trials comparing the growth speed, morphology, wet weight accumulation and nutrient quality of Fodder grown in a high light/ medium humidity situation in a lettuce greenhouse verse that grown in our low light/ high humidity fodder
The results were fairly surprising, the average wet weight and overall height of both sets were almost identical in both replications. Where I saw the biggest differences was in the actual grass morphology. The greenhouse grown set allocated more energy toward the production of roots than shoots, opposite from that of the fodder building group. These greenhouse shoots were shorter but the blades were wider and more expanded, implying that they were actively photosynthesizing at a higher rate than the closed blades of the fodder building’s shoots. These results led to the question of protein and fat allocation; “Is it better nutritionally to have more shoots or roots?”
After getting samples of both groups sent to Clemson University to be analyzed it became apparent that much more of the protein and fat within the plant is stored at the shoots of the fodder than the roots. Of these shoot samples within this study, on a 100% dry-matter basis it was also shown that the fodder grown in the enclosed structure had a higher protein content of 21.9% verse the 17.6% of the greenhouse. Similar results could also be seen in the comparison of the two sets of root samples. While comparing these two growing environment systems it seems as though in reference to production and economics it is more advantageous to grow hydroponic fodder sprouts in an enclosed and more controlled environment. This is not to say that greenhouse production is out of the question, especially if hydroponic fodder is the sole crop being grown. Like any protected agriculture crop, the benefits of hydroponic fodder must be weighed against the cost of the operation of the equipment as well as the cost of environmental control.