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.
Just a simple split valve is a good starting point for an initial irrigation setup.
Take water harvesting as far as you can. Sophisticated systems can be put in place, but even primitive techniques can be useful.
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.