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Green house Build

We have decided we can use a green house. We also have looked at various types and thought about what works best for our area, our budget and our experince level. The end result is a small greenhouse that we can build relatively cheap. We can use it to produce some t hings for market but also the more important is that we can use it to learn how to work in a green house and what sorts of things are important. Eventually we will be looking at a very large greenhouse for year round production of various types so we need to understand the systems in a way that can only be done by working with them.anna

The source for our green house.  The Plans include supply list.

There are many things that we liked about this green house. You can see that it has sturdy wood construction. We knew we could build it with a couple of people in a weekend. We also knew that it was low cost and that we can adapt it to suit our needs. One of the changes that we did was install anchors, a second door, removed the metal skirt and replaced with clear plastic, added two vents and insulated the gaps.

We decided that we absolutely had to make sure this was adequately anchored. We built anchors that were inexpensive and durable. We made them with J bolts, concrete and cinder blocks.

As you can see this created a block that was weighed down and secured with concrete but also attachable to the sill plate for the structure. This would also actually raise the structure off the ground and reduce the need for pressure treated or cedar lumber thus reducing costs again.

These blocks were then placed into pre dug holes. There are many lessons learned. If you have tough soil use a auger to drill the holes with a shovel to finalize it. It really did make a huge amount of difference in our ability to dig the holes we needed.

The anchoring of the structure is crucial but also leveling at this point. We wanted to make sure that we were square and level to help long term with the building process. We also decided to use some assembly line ideas and mass produce sections when we could.

 

Now the basic structure is coming together and the ribs are assembled.

Once you have the items assembled it goes together relatively quick. As with most construction projects when you place the plastic panels on the structure it really starts to have a rigidity to it. One of the changes we made was auto vents that were boxed out between the ribs and a automatic vent opener was attached. We also added store bought screen doors that made installing doors much easier.

The above image is of the completed greenhouse with plastic wrapped compost ready for planting. The second image is after we realized that we had a hard gravel pack 2-3 inches below the surface I manually removed the dirt screened it and placed the rocks around the perimeter. We also have learned the the vent needs something to keep it from being ripped open during a wind event.

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The finished product. We grew a tomato and peppers last season in it. The gravel caused so many problems that is why I dug it up and removed them. We also had some pest issues which placing the gravel around the outside perimeter should fix. We did not have issues with lack of pollination but were prepared to pollinate by hand.

Hope this was helpful

Doug

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Site Selection for green houses

Green houses/ hoop houses are becoming more and more common. You can even qualify for grants to help purchase a hoop house from the government. You have to check with your local NRCS contact EQUIP program and your local extension. I am going to focus on why we chose to build one. Why we chose to build it the way we did and some of the issues we have discovered. In the first year.

To begin with we looked at where we live (south eastern Iowa) so we can have pretty cold and windy conditions. On average we are around a 4 with gusts in the 6/7 range. This would preclude us from being interested in anything that was not anchored well. This would also cause us to consider not having a large vertical face.

columbus junction wind

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As you can see below we have a .25 mile lane and lots of open spaces around our little oasis. The openness allows for a great unobstructed growing day. However the lack of wind protection is a concern not only for the green house but for growing and living spaces in general. Being surrounded by mono culture crop land we thought may actually increase pest pressure in a PORT affect. Whereby our space can provide habitat for pests that is not available in the surrounding area which could affect our plants both in and outside of the green house.

oppedalfarmcrop

Do you need a green house to grow veggies and other produce in our area? The answer is a resounding NO! But, you can grow more longer and higher yields with a protected environment. Elliot Coleman has shown that with appropriate planning you can grow 4 seasons in Maine. Which is further north then we are. As a matter of fact you should take a moment and look at your latitude. We are at 41.3 degrees which is at the same level as Spain, turkey, Greece, Italy (Sardinia) to name a couple. Wiki 41st Parallel Which all have a history of long growing seasons. So without adding lights we can count on being able to produce year round. The concern becomes temperature. We can expect significant more cold then Sardinia for example. However that can be negated with both heated and unheated green houses without additional lighting.

Knowing that we are cold enough to have concerns for year round growing and knowing that we need to be concerned about the materials and shape of any growing structure we utilize. So what are the options for green houses?

The first is a very commonly found at your big box stores. It is made of thin plastic or metal. The panels are  thin and prone to breaking. It is not anchored to the ground. Nor will it hold up to any sort of long term usage you will have minor damage after the first year of regular use in our environment.

The second is a basic hoop house. It most likely has dirt floors and this version does not look to have roll up sides or direct ventilation. Dirt floors are useful for growing a larger variety of produce. Concrete floors allow you to manage weeds and pests easier. It allows for a cleaner work area and with the addition of tables may make for a more ergonomic growing. The main downside to concrete floors is increased costs and increased reliance on artificial media to grow in. NRCS does not allow (as far as I have found) concrete floors in our area you must grow in or on the bare ground. The roof is rounded which helps with shedding rain water but could be problematic in a heavy snow event.

The third is a commercial hoop house. This has roll up sides that allow for more ventilation. A Cathedral roof allows for more snow shedding then a more rounded shape. The floors may or may not be dirt and the structure can be heated or not. This size would allow 4 seasons of production on a market scale.

The forth is a fully commercial greenhouse and as you can see is actually multiple smaller structures joined together. It is most certainly heated and is more certainly concrete floors. The cost of the structure would require it to be built and utilized year round producing high value products that can be grown in various media and technologies think Hydroponic tomato or lettuce.

The fifth is a geodesic dome. Most commercial and hobbyist stay away from it for a variety of reasons. The most obvious is the wasted space. There is a lot of vertical space that cannot be used unless you are growing something like trees. The roundness also prohibits you from “stacking” the structures as you can see in number 4. They are efficient in energy usage and resource allocation.

The sixth is a walpini which is what I consider the artisan greenhouse. These are site specific as if you are not careful you can shade your growing area out for most of the year if you are to far north. They have a high thermal mass being most buried and therefore are extremely energy efficient. They are not for the hobbyist as they are labor intensive to construct.

I added the last two so you can see that there are many options to choose from when you picking what you need. So we know that we need something that can be anchored. We want to grow in ground of the cost savings and the ease of technologies for dirt working. We also want it to be structurally robust so no film we want clearn panels. So we decided to take a modify a design similar to the 1st one.

The next blog will show you what we did and describe why we did some of the things we did. Till then…

Doug