Backyard Aquaponics
A place to discuss aquaponics

Looks like you are coming along great to me. I will be interested in what you learn as you use the porous type material you are covering it with. I will keep following along...

Thank you azungal. We have placed the frame in position more or less where we are planning to set up the green house.

It looks wild and barren right now. We still want to keep an ordinary vegetable garden which we are going to move to the back area between the car port and the concrete wall. We will have a bit more shade there for swiss chard, tomatoes etc. The fence must go up again to keep our "lovely" dogs out of the garden and green house area. Now I must find another place to store our fire wood kindling for the winter months.

I wish I had that much space.
It will be great Cobus. H
Have you done anymore work?

I knocked this up on the weekend, a bit like a mini version of yours!!


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Cargs, what type material is that for shade?

Gran, I ran into a few problems with the IBC system which is delaying the completion of the greenhouse. My first problem was getting reasonable priced growing media for the grow beds. I have x5 a 210litre barrels that is cut in half so that is about a 100litres per barrel which equals a total of 1000litres of grow media. I’ve shopped around and expanded clay for the whole system would have cost me about R4320.00/ $445 AUD which is a bit above my budget I had in mind.

So I’ve decided to go for gravel as growing media. Here I ran into my second problem, most of the gravel I could get was of dolomitic origin which apparently would cause the pH of a system to rise steadily (I’m actually running tests to verify this).
I’ve widened my search a bit more for granite or quartz gravel and eventually I’ve found a supplier that was stocking granite/quartz gravel. I’ve bought 1m³ of this gravel which cost me R400/$41 AUD.

The other problem obviously with gravel as a growing medium is weight, and I’ve calculated the weight of the gravel to be 150kg per 100litres or per half barrel GB. Water is taking up another 40litres or 40kg which bring the total weight to about 190kg per half barrel. So the support structure must be really strong to support all this weight.

I’ve decided to use wood poles for a support structure which I’m currently busy planning. Unfortunately I must first complete these GB support structures before even thinking of completing the greenhouse which is covering it with the material I’ve bought.

Another problem that we had with our smaller greenhouse is too much heat on really hot days, a problem which is going to be much bigger with our bigger greenhouse. I’ve come up with an idea of building a horizontal type curtain which can be open or closed over the greenhouse structure itself. So during summer time the “curtain” that is made of shade cloth will be closed most of the time and during winter it will be open.

It's just 50% shade cloth from the local hardware, coolaroo is the brand I believe


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"Another problem that we had with our smaller greenhouse is too much heat on really hot days, a problem which is going to be much bigger with our bigger greenhouse. I’ve come up with an idea of building a horizontal type curtain which can be open or closed over the greenhouse structure itself. So during summer time the “curtain” that is made of shade cloth will be closed most of the time and during winter it will be open.:


Thats what i do in mine,i just clip shade cloth to the frame over the area i want to shade,i have left my tunnel open at either end for air flow,but it still gets hot,like you i will get around to making a frame to make it a bit more professional. Toying with the ideal of using a oscillating fan as well during the hottest parts,to shift air but also to move plants like coriander to strengthen them.

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Having Growbeds up from the floor on structures.........well these structures really have to be strong.
That's where sumptanks come to my mind again.
Originally I wanted to have a sump tank below dirt level and then everything heavy (FT and GB) just sitting happily flat on the floor.
Unfortunately space for that is not existent in my current situation, so if I ever come back to this world after this stay I will make sure that I start earlier and with a bigger area

Looks a solid design - have you got some material to place between the greenhouse film and the PVC? Apparently PVC will weaken the greenhouse film.

I was going to do mine from poly, though seeing this I might go with pvc and rebar. Do you know what the difference is between electrical pvc thickness and pressure pipe (in 20mm) - I would probably go with pressure pipe as I can source that at around $5 per 6m length.

Dasboot the plan is to have at least a gap of about 1m between the top of the green house and the "curtain" when it is closed. This will allow hopefully enough airflow between the greenhouse and the curtain then to cool it down. The oscillating fan idea of yours sounds like a good plan I’ve seen several greenhouses in the past with big fans to increase the airflow.



Gran the initial idea was to have our sump tank/barrels in the greenhouse under ground level. But due to the weight issues and soft soil I have decided to place the sump tank/barrels outside the greenhouse under ground level where it will still be isolated. Much safer that way I believe.



Mattyoga, I haven't thought about that yet. I’m going to use PVC C-clamps to clamp the material in place over the greenhouse conduit structure. This will prevent the material from shaving against the PVC. The damage that you refer to I believe is due to sun light damage?

As for the difference between wall thickness between poly pipe and electrical conduit pipe, I believe the poly pipes wall thickness is determined by its pressure class or rating. The conduit pipe I'm using has got a wall thickness of about 1.5mm. Conduit pipe is much more rigid than poly pipe. Unfortunately conduit pipe is not UV treated and it will get brittle very quickly without any protection. Rebar with a poly pipe cover might be a future extention solution for our greenhouse now that you mention it

I hope and believe, that I’ve come up with a solution to prevent UV damage to the PVC conduit structure.
I’m a bit of a Trekkie fan and I had a Eureka moment one day after thinking back of something I saw in one of the ST Voyager episodes. I’m going to use 150 micron plastic sheeting as an inner cover. I like to call it the “environmental shield” as this plastic sheeting is going to insulate the greenhouse’s heat during winter.

This plastic sheeting is not UV treated and the supplier warned me that it will only last a few weeks in the sun. I told him that I’m planning to cover this plastic sheeting, with a 100 micron woven polymer material that is used to protect plants against frost. This “Frost Guard” is UV treated according to its manufactures, and this “primary shield” will protect the ordinary plastic sheeting against UV/weather damage and also provide some shade to an extent.

The cost for the combination of these materials as greenhouse cover material is still 50% cheaper than greenhouse plastic I can buy for the same coverage area.
What I also want to achieve with this material is to prevent heat loss due to radiation during winter times at night, the clear plastic alone is not going to help very much I believe. This is also where the shade cloth “curtain” also comes into play during winter time at nights. In severe cold conditions I will close this “curtain” at night to keep frost away from the greenhouse itself. The curtain will then be open during day time in winter time as to let the greenhouse absorb maximum heat from the sun.

I believe the damage is due to chemical interaction between the PVC (plastisisers) and greenhouse film rather than UV or mechanical.

I think DWV is UV stabilsied - not sure about PVC pressure though...

Thanks. I was not aware of that. Another potential problem I must look into.

Dasboot the plan is to have at least a gap of about 1m between the top of the green house and the "curtain" when it is closed. This will allow hopefully enough airflow between the greenhouse and the curtain then to cool it down. The oscillating fan idea of yours sounds like a good plan I’ve seen several greenhouses in the past with big fans to increase the airflow.

Sorry Cobus, i didn’t make that very clear,my tunnel is 2.6 metres high,i clip the shade cloth horizontally at the 2 meter mark leaving the air gap above,with the open ends,this works well. But its a pain to put up and take down,so like you i want to build a frame making it a much simple process to slid it on and off. i will get on with this and post some pics.

Ah okay. I looking forward to see it.