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How to maintain a NFT microgreens system

Updated: Mar 13, 2020

NFT microgreens system

Visualize... by the end of this blog, you will be able to maintain a NFT microgreens system, all because you learned four very important processes, and the special reasons why those processes are so essential.

Basic layout of an NFT microgreens system:

NFT channels are to be used, these are then laid into position on a slope steel frame so that they will discharge straight into the outlet (i.e. lower) ends of the NFT channels that are connected to the drainage manifold. A PVC feed pipe is then connected to the circulating pump so that the nutrient water from the reservoir tank is delivered to the inlet (i.e. the upper) ends of the NFT channels. A small 3/16" polythene tube (one or two per channel) delivers the water from the feed pipe into each channel. These feed tubes are prepared by tapering the end of the tube that is to be inserted in the feed pipe, they can quickly be tapered using a pencil sharpener. A hole is drilled in the feed pipe than a 3/16" grommet is inserted into drilled hole. When the tapered end of the feed tube is pushed into the undersized grommet hole, a correct fit is ensured. The nutrient water flows by gravity as a very shallow stream down the channels, each channel discharging in the drainage manifold then into the reservoir tank. When the reservoir is nearly empty, the circulating pump will still contain sufficient water to maintain a supply to the microgreens crop. The rate of flow that goes to the channels can be easily controlled by placing micro valves to the 3/16" polythene tubes connected to PVC feed pipe.

microgreens root mat

Maintenance of nutrient water circulation:

Circulation loss could be catastrophic with an NFT microgreens crop. Yet, some water will be maintained within the root mat if circulation should fail, so there would be time available to restore it. How long that time will be, determines on the time of day, the time of year, the location, growing medium, and the variety of crop. It could range from 1 hour to 48 hours. It is highly recommended to have an power monitor alert system should circulation stop, because if there is no monitoring system then it is necessary to have regular checkups throughout the day to analysis that pumps are properly working. The best power monitoring system is MarCell device. The flow of nutrient water in these pipes will cease immediately when pumping ceases. Although, the drainage manifold or the NFT channels the gravity flow of water will continue for some time after pumping stops. Pumping will stop for one of two reasons only, either from a mechanical failure of the circulating pump, or from a power outage. It is extremely important to have two circulating pumps installed in the system, one in use and one on backup. In case circulation should fail because of a power outage, there should be a backup pump that can be put into use, by a automatic switch for 12 volt backup system. With these safeguards, circulation should never fail to be maintained.

root mat

Emptying an NFT microgreens system:

The logistics of emptying an NFT system are very straightforward. It is simply necessary to secure a hosepipe to the end of the drainage mainafold pipe, place the open end of the hosepipe in a drain and the system will empty itself without disturbing the flow of the nutrient water past the root mat of the microgreens in the NFT channels. Because a fraction of the flow from the circulating pump is regularly returning direct to the reservoir tank via the outlet pipe, this fraction of flow will go to waste via the hosepipe that has been secured to the outlet pipe. This loss will increasingly empty the reservoir tank. When the system has been emptied as much as possible, then the hosepipe should be removed from the outlet pipe. In order to minimize pump failure, it is best to inspect, take apart pump, and clean out buildup.

calcium hypochlorite

Sanitation and Cleanliness:

Proper sanitation and cleanliness is essential to running a successful hydroponic microgreens operation. The walls and floors of your grow room should remain clean and free from standing water and other sources of contaminates. Your water reservoir tanks should be cleaned regularly and pump filter should be checked every couple of weeks, because of debris build up. A diluted calcium hypochlorite solution can be used to clean all of these surfaces. If calcium hypochlorite is used on channels it should be allowed to dry and then rinsed off with clean water. The drainage manifold is not glued to the channels and is easily removable, because the PVC should be cleaned and sanitized on a regular basis to prevent contamination sources from forming.

Next week's post is about humidity and temperature. What would you like to see in our future blog?

Let us know in the comments.

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