Which irrigation methods work for which crops?

Courtesy of Wally S., Wally’s Urban Market Garden, Saskatoon SK

This was the burning question at  our recent online Open House on irrigation.  Get ready for the answer that drives everyone inside and outside of farming crazy: It depends. Your choice of irrigation will depend on lots of factors, including your type of soil and operation.

I use hand watering methods most of the time. I am not a big fan of mechanized systems  and specialized hoses because they are expensive and require management and maintenance. They might make you feel clever, but if you analyze the effort that goes into them, you might find they don’t really earn their keep.

Another factor to consider is potable water.  Many of you know my story, and that a big reason for my becoming an urban farmer was to ditch my expensive and elaborate irrigation system that depended on fluctuating river levels.  Now, I just turn on the tap. Potable water is the single most important issue when selling produce that is eaten fresh, because water can be the source of contamination, and using municipal water greatly reduces this risk.

Below is how I handle it for my multi-locational  an urban/peri-urban  11,000 sq.ft. farm.  But just because I prefer to hand water doesn’t mean other methods are not viable. These are the broad categories of crops just as a starting point.  We’re starting a member-sourced project in our online support group for best irrigation practices.  So consider this a work in progress.

IRRIGATION METHODS FOR SPECIFIC CROPS

Carrots                                                                                                                          > Overhead for germination                                                                                                  > > Flood  irrigate during growing stage

Cucumbers                                                                                                                              > > Overhead hand water with brush attachment  around the plant

Leafy greens: Lettuce, chard, spinach, others                                                                       > > Flood  irrigate by letting the hose with brush attachment lay on the ground.  Move around to cover area.  (mostly).                                                                                               > > Overhead hand watering (sometimes)

Night shades: Potatoes, tomatoes, peppers, egg plant                                                         >> Flood irrigate                                                                                                                       > > Do no use overhead since it can cause disease issues with these crops

Pumpkin                                                                                                                                   > > Overhead, hand water with brush attachment  around the plant

Summer squash                                                                                                                       > > Overhead, hand water with brush attachment  around the plant

Winter squash                                                                                                                           > > Overhead, hand water with brush attachment  around the plant

Pumpkin                                                                                                                                 > > Overhead, hand water with brush attachment  around the plant

Radish                                                                                                                                      > > Overhead hand water with brush attachment

Fresh herbs                                                                                                                            > > Overhead, hand water                                                                                                        >  > Dryland

SF photo Wally watering 2

Wally’s approach to irrigation is to keep it simple. He hand waters, mostly.

Standing Up To Drought

Courtesy of Wally S., Wally’s Urban Market Garden, Saskatoon SK

Most farmers usually try to plan based on following long terms trends. They aren’t fans of deviations from the norm. SPIN farmers like to change things up and experiment, and our scale of operation makes it low risk to do so. That’s a big advantage when it comes to extreme weather, which is now becoming the new normal for many of us. Here’s how I am starting to cope with it.

In the upper left of this photo you can see how my potato plot looked in mid-June.

SF photo potatoes before rain

No growth at all, because of drought. I have not seen it this dry here in years. I thought about terminating the plot, but I did not know how to go about it. Till it in, and you just have more small-sized seed potatoes. So I left it, and just did minimal irrigation, by hand, with a hose and brush attachment.

After 3 inches of rain at the end of July,  I visited the plot, and it looked like this.

SF photo potatoes after rain

Up until now, onions were my go-to crop for my peri-urban plots that needed to go for extended periods without irrigation and could get by with little rainfall. Now that drought may be my new normal, I’m going to have to push the envelope on other crops to see which ones hold up in extended dry spells. So far, it’s onions and potatoes that are helping me stand up to drought.

Newbie SOS: How do I set up my irrigation?

Courtesy of Wally S., Wally’s Urban Market Garden, Saskatoon SK

SPIN-Farming does not require elaborate or expensive infrastructure, and that includes irrigation. Everything you need to install an above the ground system that stays permanently in place throughout the season, can be purchased at the garden center and hardware store.  The best advice for newbies like this is don’t over-engineer it.

For my  100’x 50′ rented area, there is no city water, but it is beside a creek.  Can I buy a “good one” pump for $200? I read about the manifold/hose setup in the SPIN guide, and think I can use it for soaker hoses.  But if I have 60+ standard beds, is one pump feasible?  But I guess that is what manifold is for, to only use a certain portion of all the hoses at once? Or is my only option spray heads due to size?

A SPIN irrigation setup needs to be flexible. I would set up your garden in areas, with different irrigation systems tailored to what is grown in each. I am not sure what your typical rain fall patterns are, whether you are dry, or get regular rains. Some crops, like onions and potatoes, can be grown without watering, and just rely on rainfall. Also possibly beans and peas.

I would not invest in a lot of hose. If you can get a pump going, I would just set it up to run one or two sprinklers, or even just water with a brush attachment on your garden hose, and water by hand. For some crops, like potatoes and squash, you can just lay a single hose on the ground and just let it run onto the soil. Just need to move the hose around to another spot every once in a while. So I would say start very simple, and try to dryland as many crops as you can. Not all of your garden needs to be watered at once. Only certain beds and areas. Be sure to check the water quality of that creek.

Mod 2 Irrigation 1

Just a simple split valve is a good starting point for an initial irrigation setup.

 

Mod 2 Irrigation 4

Take water harvesting as far as you can. Sophisticated systems can be put in place, but even primitive techniques can be useful.

 

SPIN photo Wally watering

Because SPIN farms practice relay cropping, which involves a lot of crop diversity with all crops at different stages of growth, an irrigation system must be flexible. For instance, you might have just relayed 5 beds of spinach to carrots, and you just need to water those 5 beds. There is no point having an overhead system that can water the entire plot, when you just need to water a few beds. Instead, you would just water a few beds using a garden hose and hand held brush attachment.

Irrigation and Water Quality

Courtesy of Brenda S., Thompson Street Farm, Glastonbury CT
To avoid shocking my leafy greens, I either water in the early morning or late afternoon when the sun is set enough to cool off the hoses. We are on a well, so the hot water in the hoses isn’t that much of a problem. Sometimes I just turn the hose on and wait until I get cool water. Then I water the beds, which take about 5 minutes of running the water.

I’ve sent water samples to the lab to get tested and will continue to do this. We do not run our water through any home filtering system. Farmers who wish to process their own jams and jellies must first have their water tested and then pass a food safety class, and this is why I have my water tested.

Here in CT we have a new law nicknamed “The Pickle Bill” which allows farmers to process poultry (under 1000 birds) and process jams, jellies, salsas, pickles etc. right on the property. In the past farmers had to send birds to a slaughter house for processing, or the customers would buy the live bird first then give it back to the farmer to “process”. In addition, if farmers wanted to make jams and jellies and other products from left over fruit and vegetables,it had to be done a commercial kitchen. This bill eliminates these requirements.

This new law requires all farmers who wish to process pickles, jams, jellies etc. to have their water tested annually and have some food safety certification by an accredited organization recognized by the state health department. In my opinion, cooking in a restaurant kitchen has nothing in common with a home kitchen or canning. But, its the law and I’m complying. My well water has been tested for 2 types of bacteria and I’ve taken and passed the commercial food safety class.

Several times a week I will set up a bucket of diluted water and fish emulsion and water young seedlings. I stop using the nutrients when they are close to harvesting (about
a week before). On plants such as tomatoes, I again use the nutrients when first planted, but as they grow and begin to blossom I stop. I want more fruit than beautiful foliage on my tomato plants.

Water Meters to Track Usage

Courtesy of James K., Virtually Green, San Francisco, CA

If part of the deal for using someone’s property in your farming operation is paying for water, here is a source for water meters that you can select from to track your usage.

http://www.watermeters.com