Moveable Greenhouse Rotation as a Chicken Padock

[Poppy Putentake]

Hi all,

I have a small (13' x 18' 8") moveable greenhouse, the frame constructed of steel conduit for the arches plus some PVC conduit for the skids and ridgepole, and wood to frame the ends. (I would be glad to share the construction method with anyone who contacts me backchannel.) In devising the construction method, I borrowed ideas from several sources, especially notably these two:

https://www.chelseagreen.com/product/four-season-harvest/

https://bountea.com/articles/gothicgreenhouse.html

My greenhouse can be moved fairly easily on it skids by two persons, a man and a woman of about average strength. For the past few years, I have been moving it between two sites (next to each other, so it only moves its own length) once a year in mid-October. At that season, it is getting too cold even for the warm weather crops on the first site, but the second site has already been planted with cold-weather crops (mostly salad greens). I can harvest salad greens and some culinary herbs all winter. I also put my chicken tractor on the former site of the greenhouse for the winter.

In the spring, most of the salad greens have been harvested from the greenhouse, and I plant warm weather crops there. At that time I also plant a cover crop(example, field peas and oats) on the other site which provides the chickens with a little food before I till tit under in July and start the process again by planting salad greens there in August.

This system makes it possible to get two crops a year out of the greenhouse (with a total 14-month season!) and also makes it easy to clean up the former greenhouse site at the end of each cycle and to improve the soil there.

My thought is that if I added a third site, I could change from a two-year rotation to a three-year one, with chickens occupying one of the sites at any given time. The greenhouse footprint is a good size for a small flock of chickens. I could raise more than one cover crop each year, perhaps winter rye through the winter and peas/oats in the spring.

I'm interested in other's thoughts on this as a system for soil improvement, growing some supplementary chicken food, and eliminating weed seeds.

Poppy

 

[cavemanrich]

Post some Pix. A picture is worth more than a 1000 words.
WISHING YOU BEST...........................

 

[aart]

(I would be glad to share the construction method with anyone who contacts me backchannel.)

You do not want to share it publicly? I would love to see it, many others here would too.

 

[Poppy Putentake]

aart wrote

You do not want to share it [your construction method] publicly? I would love to see it, many others here would too.​

I thought that would be off-topic for this forum, and also, my (very detailed) writeup is not ready yet. I could post that to the files section when it's ready if that's okay. In the meantime, here is a quick version. I'll try to send pictures soon. (I can also send a draft of the detailed writeup backchannel.)

Starting from the ground, the greenhouse rests on skids made of 1" I.D. PVC electrical conduit. This comes in 10" lengths, so these are spliced together with inside plugs about 6" long made of 3/4" I.D. PVC. The smaller size conduit has a nominal outside diameter of 1.001", but by sanding the outside I got the diameter down so that the plugs fit in just right. I fastened the pugs with two small screws on each side rather than glue, but I suppose glue would work too. I did not use wood dowels because I thought they would not last in a damp environment near the ground.

For when I want to move the greenhouse, I made two skid ends out of a 90 degree 1" I.D. PVC elbow cut in half. Each skid end has a plug permanently fastened in halfway. (I used 3/4" PVC conduit for these plugs too, although since they are only used for a short time, wood would be okay too.) The other half of the plug goes into an extra 3" length on each end of each skid. With the skid ends inserted, the skids have a turned up end facing the intended direction of travel. The greenhouse is then like a giant sled and can be pushed without too much trouble.

The (UV resistant) polyethylene sheeting that forms the outer skin of the greenhouse is supported by 9 bows spaced 28" apart (I think 30" would work too.) The bows are made of 3 pieces each of 3/4" steel conduit. The two side pieces are about 10" long and have a bend in about the middle. The top piece is much shorter, with its bend forming the peak of the roof. The three pieces are joined with set-screw fittings made for steel conduit. There are also four purlins (lengthwise support members) made of 1/2" I.D. steel conduit running the length of the greenhouse, plus two diagonal braces at each corner, made of the same. These are all fastened to the bows with through-bolts. This means lots of holes drilled through the steel conduit, but there are ways to drill these fairly rapidly and in the precisely right spot. I figured out the measurements for where each hole was to go in each piece of conduit ahead of time and pre-drilled each piece.This involved lots of figuring, measuring and labeling, but in the end it saved lots of time because once all this was done, the whole framework went up in half a day with no need for temporary fastening, measuring, or squaring.

Each skid has 7/8" diameter holes drilled along it, spaced to receive the ends of the bows, and those ends are secured with long finish nails that go through pre-drilled holes. There is a ridgepole, also of 1" I.D. PVC pipe, fastened to the top of each bow. (The ridgepole was notched for the bows, just by drilling 7/8" holes at each bow station and shaping the holes with sandpaper wrapped around a 3/4" dowel.

The two end bows are framed with 2" x 3" wood. Both ends have a long 2x3 beam 24" above the ground fastened to the steel bows. This needs to be stepped over to get in but with a cement block inside and outside forming a step, this is fairly convenient. In retrospect, I think that 18" above the ground would be sufficient to clear the crops on the ground when the greenhouse is moved each October. Those crops are mostly salad greens and not very high.

One end is framed for an entry door with a vent above , the other end is framed with the same kind of vent (plexiglass) at the peak , plus two larger openings, one above the other, for larger vents. The larger vents are made of aluminum screen window framing glazed with clear plastic sheeting. These are coupled to the vent at the peak with cord.

The top vents at each end are fitted with Univent window openers (Manufacturer:J. Orbesen Teknik ApS. See.) They are fastened to a wooden piece fitted to the peak of the bow where it crosses the ridgepole.

See: http://www.orbesenteknik.com/en/univent

The book by Coleman advised using horizontal pin hinges for the vents. I could not find such an item at any local hardware store, but devised some that are cheap and simple, and that have worked very well. This takes advantage of the fortuitous coincidence that 1/2" I.D. PVC pressure pipe fits into 3/4" I.D. PVC pressure pipe just slightly loosely.

I drilled 7/8" holes into the wood frames on the sides of the vent openings and gently tapped in short lengths of 3/4" I.D. PVC pressure pipe. Then I attached pieces of 1/2" I.D. PVC pressure pipe horizontally to the vents with those U-shaped strap fittings made to attach conduit to walls. (The fit was too loose, so I shimmed the straps with pieces of "plastic canvas" -- that plastic mesh sold at sewing stores.) A nice feature of this kind of hinge is that with this shimming, the pieces of 1/2" PVC pipe (acting as the pins of the hinges) fit just tightly enough to stay put, but can be easily slipped out to install or remove the vents.

The smaller vents at the peaks to the ends with the univents can have the hinges at any point, but near the middle works best. The larger, lower ones close by gravity only and should be hinged slightly (1 or 2 inches) above the middle so the lower part will be heavier. If the hinge is too far above the middle, though, strong winds will push the vent open because of the lower part having more area.

The door is just a frame of wooden 2 x 3s covered with plastic sheeting. I used a plastic rebar safety cap as a (passive, non-turning) doorknob. It is important to have a diagonal brace that goes upwards from the hinge side towards the upper corner on the latch side, as this configuration will resist the door's sagging tendency better. See this site for a detailed explanation:

http://thecarpentryway.blogspot.com/2009/10/bracing-situation-iv-design-for.html


It would also be good to put extra fastenings into the frame at the hinge side of the door, as that is where most of the strain from the weight of the door is.

The ground inside the greenhouse is arranged in four lengthwise beds. The two middle beds have more headroom, and in the summer, I train tomato plans and cucumber vines up cords attached to the purlins, which are directly above the center of those beds. The side beds are good for peppers and melons.

In the winter, I grow salad greens in all beds, covered with non-woven fabric row covers supported by wire hoops. The area near the door is a good place for culinary herbs. It is very pleasant to visit the greenhouse in late winter and find it warm and sunny, sometimes even with flowers blooming. (Pansies winter especially well in the greenhouse and I have had them (barely) in bloom continuously all winter.)

With this system, the greenhouse can do double duty, producing both a summer and a winter crop, with a few months in between to tidy up the site and improve the soil.

Poppy

 

[aart]

I thought that would be off-topic for this forum, and also, my (very detailed) writeup is not ready yet

Nope, mobile coops fit well, there's a deficit of them IMO.
Many folks are interested in combining gardening with chicken housing,
as long as they actually house chickens too, it fits here.

There's also a gardening section here:
https://www.backyardchickens.com/forums/gardening.16176/

Detailed pics to illustrate the text is always good.

I could post that to the files section when it's ready if that's okay. In the meantime, here is a quick version.

There is an 'articles' section here rather than a 'files' section.
Here's an article example, my mobile hoop coop:
https://www.backyardchickens.com/articles/aarts-hoop-coop-chicken-tractor.72211/

 

[Poppy Putentake]

Hi all,

I'm posting some greenhouse pictures in response to requests. Here is the interior of my greenhouse in midsummer of its second year.

Note the three vents open at the far end and the hanging cucumbers right foreground.
The yellow object on upper left is just a piece of plastic cut from a plastic bottle and smeared with Vaseline as a preventative trap for greenhouse whiteflies. The first year I had these pests but they have not returned in 5 years since. The white object on the left is of Styrofoam and is a cover for an electronic remote temperature probe. The vine on the right is red morning glory (Ipomoea coccinea). Pretty flowers, but this subtropical plant grew a little too well in the jungle heat inside the greenhouse and really took over its spot.

Here is what the vents look like from the outside. This was from the first year, before I made some modifications. Note that he PVC pipe does not need to go all the way across the lower vent -- all that is needed is short pieces on each side. The wooden dowel across the upper (plexiglass) vent is needed, though, as it keeps the (flexible) plexiglass from bowing. (It is fastened in the middle with a wire tie.) You can see the white cord that goes from the end of the Univent at the top of the upper vent, through some leads, and then down to the bottom of the lower vent, so that the two vents open simultaneously.

Here is what the upper vent looks like up close (this year). Note the leads (a black plastic ring and a screw chain link) for the line connecting the two vents. I have recently arranged the line so it is doubled at the top connection (the screw chain link). That way, the line to the lower vent moves twice as much and the lower vent opens wider. At the same time, I put a little more slack in the line , so the opening of the lower vent is a bit delayed. Those two changes make the temperature feedback to the lower vent more sensitive.

Since the movement of the of the hinges and of line through the leads is very slow, and only happens twice a day, friction and wear are not an issue and these simple parts work very well.

The bolts through the PVC pipe to fasten it to the plexiglass on the two sides are unnecessary -- one, or maybe two, U-straps would do the job and would make installation of the vent more convenient.

Here is a picture of the simplified arrangement as I now have it on the lower vents. The 1/2" PVC pipe slides into a piece of 3/4" PVC pipe (edge just barely visible in the wood frame).

This is the greenhouse the first winter. Shedding snow has never been a problem. Note the single diagonal brace along the upper hinge-side corner and the rebar cap doorknob. One plus about having the doorstep raised above ground level is being able to open the door even if there is deep snow.

The red and blue clips (made of plastic water pipe) along the end bow were eventually replaced in most spots with a product called "Wiggle Wire", which holds the plastic on better. (I did leave the clips on for the 2' near the ground so I could more conveniently open the bottom "skirt" on the ends for extra ventilation.) The force pulling the plastic off the end bow is greatest in the middle, near the bend, and that is where the Wiggle Wire is most needed.

Here is the diagonal bracing at one corner. (This much diagonal bracing seems to be adequate, but if I build another greenhouse, especially if the side walls are closer to vertical, I'll put an additional diagonal brace between the first two bows up near the peak (both sides, both ends, so 4 braces). That would also provide a few additional points of fastening between the framed end bows and the rest of the structure.

(BTW, I eventually eliminated the piece of wood running along the bottom of the bows, and just attached the Wiggle Wire channel directly to the bows. Simple is often best.)

Here is what the skid tips look like. As you can read on the label, they are made of the halves of a 90 degree 1" PVC conduit elbow. The inner part is made from 3/4" PVC conduit, but a wooden dowel would work too, as they are only used occasionally for moving the greenhouse and are not outside near the damp ground all year. Note the pin holes and the pins made of Aluminum roofing nails. (The red paint is to make them harder to lose.)

Here is the corner of the greenhouse with the skid tip attached, pins in, and all ready to slide. Note the end of the diagonal brace bolted to the end of the bow, and the end of the bow stuck into the PVC skid. You can also (barely) see the heads of the two finish nails that anchor the bow end into the skid. (Maybe not strictly necessary, as friction and gravity hold it there too, but I like things secure.)

Finally, here is the greenhouse in September, still growing warm-weather crops, but poised to move next month to its winter site, which is already planted with salad greens. (Since this is is the north end, I used opaque white plastic there instead of the UV-stable sheeting that's on the other sides.)

I would be glad to give even more detailed information to anyone interested in building their own moveable greenhouse like this one.

Poppy