Appropriate Irrigation

We receive about 40 inches of rain per year in Southern Indiana, and it is spread out fairly evenly. Every month of the year we get about 3 inches except March, April, and May when we get 4-5 inches.

But these are averages. There are dry months, dry spells, and even mini-droughts. There are also floods. Just this year, we had an unusually dry April until the last two days of it, when it looks like we’re going to make up for the rest of the month, as seen below.

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An excellent demonstration of what tillage does. Note that where there are plants growing there is little if any surface puddling or runoff, and where there are no plants it all just washes away! An advantage of raised beds is that they capture much of the runoff in the ditches around them.

While most field crops–plants like corn, beans, wheat, etc.–can  handle ups and downs, consistent moisture is important for many wimpy garden plants, especially when trying to get them to germinate. Most gardening books say that most garden plants need about an inch of water per week for good growth. We don’t get that much rain, and there are certainly weeks that pass with NONE. This is why I think that for garden plants at least, irrigation is something to be strongly considered if not essential.

Now, how to go about irrigation without it spiraling out of control? People go out and spend a considerable amount of money on irrigation systems and even more alarming amounts of money on water from municipal reservoirs to grow garden plants. Almost always this results in the plants costing more to grow than you can buy them for, and this isn’t including all the other costs involved. Essentially, irrigation systems can quickly make gardening not worthwhile. It took me a while to figure out how to overcome this.

First I considered the source of the water. I guess we are fortunate to have three different sources of water at our disposal. We have chlorinated municipal water, a shallow dug well with a pump, and, of course, rainfall. Municipal water is too expensive to irrigate with, and I fear that our well could never keep up with the volumes of water needed for a large garden (it is just fine for watering livestock, however), so I thought about rain. If you go on YouTube or wherever you will see all sorts of clever rainwater capture schemes, almost all of them involving plastic containers, and almost all of them not worth the trouble. In Indiana, we do not need water so desperately to justify spending thousands of dollars on plastic plumbing and cisterns, especially when we have such clay rich soil that simply digging a hole in the in ground holds water.

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I dug this tiny pond with a rented mini-backhoe (a Terramite). It took a few hours and cost $200 total. It was more of a proof of concept than anything else. I simply didn’t believe that our soil would hold water. 

The first matter of a pond is to figure out a few things and place it as best you can. I recommend reading every pond book and resource you can. Earth Ponds is a good start. Pond Lovers is a good read, but a bit whimsical. And The Biointegrated Farm is an excellent place to learn about small ponds. In my situation, it was fairly easy to figure out what to do, since there are but a few possibilities. There are no natural creeks on my place, so a dammed up creek type pond was out of the question. If there are any springs on my place they are probably insignificant, and I have not found them besides. This leaves me with basically the excavated (or dug) pond–a hole in the ground that collects runoff. I do have a decent watershed in my pastures and garden of about 8 acres, and I dug my “test hole” in the lowest point. To my surprise, it filled up in about 3 weeks in November and it held water all winter.

We had a spell of dry weather in February this year, and that is why I had the pond dug by an excavator who used a heavy track loader. I think a track loader is the ideal piece of machinery for this kind of job. It can work like a bulldozer, but it can also lift up the dirt and pile it up and rank it, which makes it possible to get the topsoil back on top when it’s all done. It also has those tracks to pack down the banks of the pond.

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It is very apparent the difference between the tan clay subsoil and the dark brown topsoil. At only a few hours following completion the pond began filling. 

I highly recommend shopping around for excavation contractors. Any of them can make a hole in a ground, but not all of them really understand how to make a pond. Ask them questions about ponds, and listen to what they say.

In all this pond didn’t take 8 hours to dig. Considering that the pond will hold about 75,000 gallons of water, it is bargain compared to plastic barrels, and will hold more than enough water for a 1 acre garden, yet it only occupies less than a tenth of an acre of surface area (60 feet in diameter). It also provides a place to grow fish and ducks and a recreational feature. In all, ponds can be very valuable, and it captures water that would otherwise run off my property, or leave via drain tile, along with soluble nutrients.

Now that the source of water has been solved, how to get the water onto the garden. Since this is pond water, which has sediment, drip irrigation or soaker hoses are out of the question. The emitters would get plugged up, and it would require a complicated system of above ground settling tanks and sand filters to work. Of course, these would need to be drained every fall, too, so they wouldn’t freeze.

Flood irrigation could work, but I think it is very wasteful. Since I do raised beds, I want the water on the bed and excess water to run off in the ditches in between. Watering the ditches doesn’t make much sense.

And toting water is not the answer. You just can’t tote worthwhile amounts of water.

We have the Chinese to thank for the solution. I’ve long admired historic China’s systems of ponds and dikes and human-powered pumps used for irrigating, and I now admire this wonderful little Chinese made pump from Harbor Freight.

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Everything you need is in this picture: the pond, the pump, the intake and discharge hoses, and a bucket of pond water to prime the pump with. Of course I put about a quart of gasoline in the pump, which lasts for around an hour. 

This little pump is so handy! It weighs about 30 pounds and is easily carried around by an adult. It has no problem pushing water through ordinary 3/4″ “farm hose” at a pressure and flow rate that exceeds any household supply. It uses very little gasoline and isn’t terribly noisy. It starts right up, and when the job is done, you just walk it away and put it in a  shed. It’s four-stroke, too, so it runs cleanly, efficiently, and doesn’t require you to mix oil and fuel.

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My floating water intake solution. I now think that flipping it upside down would work, too.

These kind of pumps are for “clear water.” They cannot handle large debris, and they also work harder if they have to draw water up considerable distances. This is why I lashed the screen intake to the non-collapsable intake hose to this old pallet. The pallet floats keeping the screen intake near the surface but below it, and it keeps it from running aground and pulling in mud and debris. Bonus: pallet provides egg laying substrate for Fathead Minnows!

A hundred feet or so of hose and a few plumbing fittings are all you need to get irrigating.  I prefer hand watering to sprinklers because some plants need more water than others, and also because I like to watch the water as it absorbs into the soil. It helps me gauge how much I need to apply. I like to see it take a few seconds for the water to absorb, but I don’t like to see puddles.

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The pump moves a rated 35 gallons per minute (now you see why it is hopeless watering with cans), but I run it at somewhat less than full throttle. At this rate the entire garden can be watered in about an hour, and in that time the pump uses less than a quart of gasoline (about 60 cents worth). Since the pump is gasoline, it is highly portable and there are no extension cords running all over the place (which can be dangerous with water).

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