Growing Strawberries in a Self Irrigating Gutter (SIG).

self irrigating srawberry container

I got this idea from Larry Hall, who made a video showing how he uses gutters as self watering containers. In the first part of the video Larry shows how to use a gutter to supply water to a row of pots. In the second part he shows a two gutter strawberry growing system. I decided to build Hall’s self-irrigating gutter (let’s call it a SIG) to grow strawberries. Here’s how I did it:

With some scrap wood I made a support system for the two gutters–one gutter holds water and the other holds soil. I sealed the ends of the two gutters with silicon putty and secured the gutters to the wooden support with screws.

float valve in self irrigating gutter system

Next came my first trip to a hydroponics shop (there’s one on every corner in Los Angeles), to get a float valve. The float valve, similar to the one in your toilet, automatically fills the lower gutter with water as needed. I tried to fit the float valve through the end of the gutter but this kind of DIY bulkhead fitting is difficult to pull off. I ended up mounting the float valve above the gutter with a pipe strap, as you can see in the photo above. I cut the upper gutter around 10 inches shorter than the lower one so that I could access and maintain the float valve.

mesh cup

The second item I picked up at the hydroponics shop was a bunch of 3 inch mesh pots. These hang down into the lower gutter and wick water up into the soil. I cut circular holes in the upper gutter using a hole saw, and fit the mesh cups into the holes.

Next I filled the upper gutter with potting mix (note that with self watering containers you have to use potting mix, not regular soil). And all self watering containers need mulch of some kind–I just happened to have a roll of vinyl billboard material that my neighbor Ray gave me. I stapled the vinyl to the wooden gutter support and stretched it over the top of the soil. I cut holes and planted my strawberries about 8 inches apart.

rain barrel

Rain barrel. The white pipe on the left is an overflow pipe that drains to the street.

The float valve is connected to a rainwater barrel. You can read more about how this barrel is constructed in one of our older posts. Since SIGs need to be watered even when it’s raining, this is a perfect use for a rain barrel. I will have to fill the barrel with municipal water during our dry season.

Problems
There’s a lot of plastic here, specifically PVC, which is an environmental and health disaster. I have two questions–how much PVC is leached into the growing medium and how much of it would be taken up into the fruit? I don’t have an answer to either. If you know of science-based information (i.e. not Livestrong articles) on PVC and growing food please leave a link. Generally, plants do not take up toxins into fruit so I’m not losing any sleep thinking about eating a few strawberries grown in my small PVC SIG. I might think twice about eating greens grown in PVC.

The other issue is the use of peat moss as the growing medium. Peat moss is unsustainably harvested (see Horticulture professor Linda Chalker-Scott’s article on this). Coconut coir, in my experience works great, but not in self watering containers. If you know of a peat moss alternative for self-watering containers, please comment.

There might also be mosquito problems with the standing water in the lower gutter. This could be countered with a mosquito dunk.

strawberries in gutter SIP Advantages
I can now grow food in an otherwise useless space–the top retaining wall in our front yard (we live on a hill). I can also, finally, make good use of my rain barrel. I was also able to recycle a bunch of scrap wood and some billboard material. And, unlike hydroponics, no electricity or liquid fertilizers are needed. If this system works out I’m eying the top of our garage for more SIGs (our garage is at street level below the house–we look down on it from our front porch).

I think there’s also an opportunity for an entrepreneur to make a non-PVC version this gadget out of food grade material such as HDPE. With a custom design you could also enlarge the upper, soil container gutter as well as creating a sealed mosquito proof lower container. But you would have to sort out who owns the patent on self-watering containers.

And many thanks to Larry Hall for sharing this cool idea!

UPDATE 4/30/2013: One side of the strawberry gutter sprung a leak due to a poor seal on the end of the gutter. I was able to fix it. One thought about the design is that you should leave both ends open and the gutter ends accessible so that you can make repairs. And make sure to use a sealant appropriate for gutters.

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14 Comments

  1. Could you put down a liner in the potting-mix portion to keep it away from the gutter plastic?

    Can’t wait to see these grow.

    • Perhaps. But I really need my own lab and staff to figure out these sorts of problems. Will have to sell a lot more books! Or maybe we can pool resources with the GRG. Looking forward to seeing what you’re up to this season.

  2. For mosquito control I walk about the yard with a bottle of Dawn. I put it in the birdbath by the drop and anything else that has water standing. Dawn breaks the surface tension so that mosquitoes cannot land on water to lay eggs. If you ever come across standing water, you can see the mosquito larvae hanging from the surface tension of the water. Put a drop of Dawn in the water and the larvae will drop away when the surface tension disappears. They fall like raindrops to the bottom of the container as they suffocate.

    If there are areas of standing water, dilute the Dawn with lots of water, 20:1, and squeeze the bottle to squirt/disperse it over a large area. There are lots of home remedies that work. Okay, I will quit.

  3. I have had Linda Chalker-Scott’s page open for quite a while now, and return to browse through it when I have a chance.

    However, her post on this is long on principles and short on data.

    Eliot Coleman has a teeny bit of data, and says: “Mr. Coleman explains that the anti-peat movement began in Europe where the population density and long-time use of their peat resources has created the necessity to look for alternatives to preserve the peat bogs. However, in North America, as of 1995, only .02% of peat lands were used for harvesting. Even if peat use has increased 100 fold since the publishing of Mr. Coleman’s book, that is just 2% of all available peat land. He points out that peat is forming faster than we can use it and is therefore, by definition, a renewable resource in North America.”

    Coir or Peat? Which should you use?

    I will never use coir because it has to travel so far to get here. It would be great to see some real analysis of North American peat mining, if anybody knows where to find such a thing.

    • This is one of those thorny issues that’s difficult to get to the bottom of. I have to say I have not really made up my mind. I use coir sometimes and peat sparingly.

  4. Are you sure you want to hold a copper strap with drywall screws, outdoors? I’d expect galvanic corrosion to be pretty harsh on that setup.

    Polyvinyl chloride is too large a molecule (thousands of Daltons) to leach into water.

    Vinyl hoses have plasticizers in them, which can leach. Pthalates seem to be a problem, but I’d worry about them more in food storage or children’s toys, where soil microbes have no access to them: I’m pretty sure pthalates are biodegradable. The warm water from a garden hose is probably not potable for this reason, but if you let it get good and cold, you’re probably OK.

    The solvents used to weld PVC pipes together are probably not salutary. I probably wouldn’t let a child drink from any PVC irrigation system less than a couple years old. In this case too, though, I’m pretty sure the stuff is biodegradable, poorly soluble in water, and very little of it will find its way into food via a flood irrigation system.

    All polymers contain traces of free radicals and oligomers (very, very short polymers), to varying degrees. This could be a problem in styrene-based polymers like ABS (source of much of the “new car smell”). I don’t think it’s anything but an aesthetic issue with polyethylene and polyisoprene (natural rubber), since both of those monomers have been in our environment for millions of years: ethylene is released by ripening fruit, and human skin emits isoprene (some try to explain latex fetishism on this basis, but who knows?).

    Vinyl chloride is nasty stuff, but apparently polymer manufacturers have gotten a lot better at using it since the 1970s, such that there’s very little free monomer in any but the oldest samples of PVC resin. It also seems that a low solubility in water makes this less of a problem:

    http://www.dnr.mo.gov/pubs/pub2123.pdf

    One way to reduce concerns would be to include some biochar in your growing medium. Generally speaking, the less water-soluble a substance is, and the lower its concentration in the irrigation water, the greater a proportion of it will end up trapped in the charcoal. I’ve also read that biochar can foster fungi, which are the organisms best able to break down difficult organic molecules (e.g., they were the first to crack the problem of lignite, an event which ended the carboniferous period) and are good for perennials like strawberries.

    Last, you could do some very coarse monitoring for toxic chemicals, and prevent mosquito outbreaks, by keeping a fish or two in the lower gutter.

    • Thanks Joel for your thoughts! Extra points for catching the galvanic reaction issue (they are deck screws, but I might still have the same problem). You’re hired at Root Simple Labs.

  5. what strawberries did you use? June berring or everberring? and what kind of yield do you expect for this size set up? That’s my new criteria for growing food now, will it be a useable yield or am I using a certain amount of space all year long for a single meal. thanks

    • I planted Chandler and Eversweet–the only ones I could find at my local nursery (missed out on bare root season). I have no idea what kind of yield I’ll get but I will definitely report back on the success or failure of this project.

  6. Hey there Erik,

    Can you post some photos of the top gutter with soil in it so I can see how that nests into the bottom gutter?

    Thanks

    John

  7. Aluminum gutters are available at Home Depot and other home improvement stores also you could buy the larger size 5” or 6” instead of standard 3”-4”. Just a thought…

  8. Pingback: Self-Irrigating Gutter Update | Root Simple

  9. Pingback: How To Grow Strawberries In Raingutters | Live Love Fruit

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