Water Sanitation Series Part 1: Identifying potential problems before they start

Spring is just around the corner, and this is historically the time of year where we get more calls about disease pressure and problems in the crop.  This year, we’ve decided to run a series of blog posts about water sanitation to get you reflecting on your own irrigation system before you are faced with a problem.  Posts over the next few weeks will focus on  identifying problems in the greenhouse, interpreting lab test results, on-farm methods for disease monitoring, water treatment technology options and more.  These will be good refresher resources, so make sure to bookmark them for future reference.

Ever wonder how water related disease issues just seem to pop up out of nowhere? You’ve never had a problem before, but suddenly things just aren’t looking right. The truth is that problems often go unnoticed while pathogen levels are low.  Knowing potential innoculum sources and practicing good preventative measures can help to reduce the risk of a bigger problem.

Cleaning your cisterns is a big job, but it can save you from a big hassle.

Your irrigation water can be a potential source of innoculum.  In your own operation, you might rely on rainwater, well water or city water .  Your water sources might also change throughout the year, depending on your production needs and the availability of any given source. Knowing the quality of your water is a must for avoiding problems.  The cost of a regular water test may be worth it if you can avoid costly applications of corrective fungicides.  Aim to take at minimum seasonal samples of your water to ensure that it is free from contaminates. Knowing the attributes of your irrigation water can also help you to tailor your fertigation program, a win-win!

Your water storage method should also be considered.  If you rely on rainwater, you might collect if off the greenhouse roof and store it in cisterns for later use.  When was the last time you cleaned your cistern?  It’s certainly not an easy job, but it’s a preventative measure that could save you a lot of hassle in the long run.  This is easiest done in a slower production time, but should be a yearly priority to avoid future problems.

Ensure that irrigation lines are cleaned before new crops go in.

Next, think about how water travels around your greenhouse.  Do you use overhead irrigation booms, flood floors or spaghetti lines with drippers? When was the last time they were cleaned?  Clogged drippers and low irrigation output can be clues that biofilm is lurking in the lines.  You might also notice film on pots that are sub-irrigated. Make sure that cleaning lines, floors and boom nozzles is a part of your seasonal sanitation routine.

Map the path of water through your greenhouse.  If you end up with a problem, this is a resource that can really help to narrow down the source.  Think about all water sources and where they go to in the greenhouse.  For example, you may have one cistern that feeds a propagation section, and a second that feeds the rest of production.  The production cistern pumps water to zones in order of their distance from it.  Your potting line might have water coming from a separate source than the rest of the greenhouse. If you have a crop that you hand water on occasion or other special cases, these should be noted in your plan as well.  Check out this example map to get you started:

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A map of your farm can be adapted to show where water flows from and to. This can really help in the event of a potential pathogen problem.

Looking for more water resources?  A booklet of Best Management Practices for Water & Fertilizer Use for Greenhouse Floriculture Production is available on our blog or in hard copy at the OMAFRA office in Vineland.  This is a great resource that helps you characterize and manager the water on your farm.  There are also resources from the University of Guelph and Flowers Canada Ontario on the additional resources tab of our blog.

If you need to send a water sample away for analysis, there are several good testing options across the province.  Sample preparation information for the University of Guelph Agriculture & Food Laboratory and SGS Lab Services can be found on their webpages.


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