The farm is a beautiful, peaceful place where plants grow vigorously using ample supplies of rainwater… sometimes. Most of the time, we rely on our irrigation network and a thoughtful approach to scheduling waterings. Much water is needed, obviously, to maintain thriving crops, but supplying water at the wrong time or in the wrong place can have harmful consequences.
At PFP, irrigation is really important because we’ve got awesome soil. Really. It allows us to get outside and do fieldwork before neighboring farmers can, and it can be tilled most of the time, because it drains so well. Additionally, soil is constantly losing moisture through evaporation, and plants lose a large amount of water through their leaves via evapotranspiration (the loss of water to the atmosphere due to the plant’s respiratory processes).
Whenever we activate irrigation at PFP, the timing is strongly dictated by the weather, as you might expect. As a general rule, mature plants lose water through evapotranspiration at a rate of 1 inch per week; therefore, this amount of water should be supplied by the weather or by the farmers. Healthy plants and soils should experience wet periods and dry ones, and so this inch or so of water has to be applied at appropriate intervals. It is also important to avoid overwatering, as it encourages weed growth. Remember this, as it is true in your garden too!
When you think of irrigation on the farm, I hope you think of the grand jets produced by the overhead sprinklers. I won’t lie: I love turning those on because of how cool they look. They are used for most leafy greens and many root vegetables. These sprinklers have a diminutive cousin, aptly named microsprinklers, that are used especially with freshly transplanted crops. They produce a mist that is much gentler than the droplets produced by larger sprinklers, and are good for young and fragile plants. Overhead sprinklers are easy to set up and are portable, but they allow for evaporation to occur, since the water is sprayed into the air and rests on the surface.
Another large component of our irrigation system helps avoid some of the problems described above: drip irrigation. Drip lines are installed in beds of tomatoes, peppers, potatoes, onions, cucumbers, melons, strawberries, blueberries, eggplant, squash, and others, because these crops are especially susceptible to bacterial and/or fungal diseases. In these beds, irrigation water is supplied underground. Disease spreading is minimized, as leaves do not get wet and soil does not splash onto plants, except when rain falls. Because the ground isn’t covered in water in this situation, drip irrigation helps to minimize weed growth, as well.
Drip irrigation is so effective that we put up with the labor required to install it each season (though the task is made more efficient by a tractor implement that buries drip tape and lays down biodegradable plastic mulch!). Some crops would be nearly impossible to grow if we could not irrigate underground because of disease pressure, including tomatoes, winter squash, onions, and strawberries. When enjoying fine produce this season, be sure to appreciate the irrigation system (and your farmers!). Don’t hesitate to look around at the network while picking; the farmers are also eager to tell you more if you are curious!