Backyard Aquaponics
A place to discuss aquaponics

Who has or is thinking of building or purchasing a greenhouse (the types with clear plastic covering - maybe they are actually called hothouses?) to house their system.

I have given this some thought, primarily as a way to keep the rain out of the beds and fish tank and to keep the setup warmer in Autumn/Winter.

Obstacles as I see them include:

- initial cost and the ongoing cost of replacing materials that deteriorate
- keeping system cool in summer, the greenhouse would surely just add to the already hot temperatures (in Qld). Though I assume that putting a shade cover on during the hotter months would assist in this regard?? (I have no experience with greenhouses)
- High humidity, meaning more problems with fungus, mildew etc on plants
- susceptibility of the covering material to damage from hail

Some of these problems are no doubt able to be overcome by spending huge amounts of money (something I cannot do). Those houses with manual or automatic opening ventilation roofs would for instance help with the heat problem. You can buy shade covers and hale covers etc to help with some of these issues.

If I can avoid building any type of structure I will do so - but I am not sure this is realistic. I have a 3 bay shed near where my system will go, so may try and have the fish tank in there to help control temperatures. The beds will be outside and will be exposed to rain, not a problem provided I have some overflow mechanism on the fish tank. Al the same I will still need to give consideration to the hothouse/shadehouse option, so am interested in what other people know or are doing in this area.

If making my own I would probably use gal pipe for the frame. I could use a hydraulic pipe bender to make the arches - putting slight bends small distances apart, but this seems like a difficult and tedious way to do it. DOes anyone have experience in doing such pending of pipe. What are the options.

Thanks.

Hey VB,

Yes i am still considering a hot house.

First i was going to because i wanted to grow unseasonal veggies
Then i wasn't going to because i realised that daylength was also important

NOW i'm probably going to again because the water temp isa dropping close to 10C during the night!

I have looked in depth at the poly tunnel design so far has the most merits for me. A friend has a tree farm and uses both small ones and huge ones. he's also given me some info.

Its the cheapest
Its insulating properties (inflated double skin) are outstanding.
The outside can be "white washed" during summer cutting down temp.

Down side are;
they look a little ugly.
The plastic used to degrade after a few years, but improvements in the plastics have come a fair way. my mate has had a 30ft one standing for 4 or five years and the films are still ok.

I'm worried about the look though as i'm on a large suburban block not a farm

As an experiment, I may weld up a small hot house 3.6m long by about 2.0m high by 2.0 wide from 1/2 inch square "tube" and have an inner AND outer wall of clear plastic. Not too sure what the material is exactly, but its like the stuff you can buy at bunnings and is about 1mm or so thick.
I've found a local place that sells it for about $4 per linear metre ( i think it was abut 1.8m wide). I have seen this stuff used as an outside wall for a large "shed" in the country and its been there a few years and looks brand new.

The idea will be to place one seet on the out side of the frame and one sheet on the inside of the frame. Thus forming an insulating pocket of air the same way the "poly tunnels do, but without the need for a little fan.

Will keep you informed.

have you tried insulating your tank VB?

I think a "half" thickness layer of f/glass insulation held on with a wrap of silver foil insulation around the tank would do wonders. just a kooky idea

If you do use the f/galss insulation protect it from the rain, as it becomes sort of useless as an insulator if it gets wet

STEVE

To greenhouse, or not to greenhouse??? My water temps aren't too bad here yet, though the silver perch have slowed down their feeding a little, and they aren't eating very much in the morning. Have to save feeding until later in the afternoon when they have warmed up a little..

VB, if you have your system beside an existing shed with the fish tank inside, and the growbeds just outside, you can possibly make a lean-to style greenhouse, off the side of the shed, then you already have one greenhouse wall (the shed wall). The lazerlite type sheeting I have used covering mine seems like it's going to last pretty well, I've only had it up for a couple of years now, but I've had no problems, and I think it would do well in a hail storm as it's basically just like the material coke bottles are made of, very flexible.

It would be reasonable inexpensive to use a couple of pine logs as upright posts and some recycled 4x2's etc to construct a basic roofing frame attached to the side of your shed.

With my system under the clear roof, the main problem is that the wind howls through it in the winter making it very cold. I have been contemplating using some thick shade cloth, or maybe some weed matting type material, that I could attach to the sies of my pergola to keep the wind out during winter.. Black weed mat type material could be fairly good as it would help heat up the inside as well as keeping the wind out, and if you use a large piece of dowl, it wouldn't be to hard to rig it up so that you can just roll the side sheets up for ventilation when needed.

I have seen someone make a very cheap greenhouse using black pipe bent into arches, held in place by star pickets banged into the ground, then plastic slung over the top... A little like people might do for bird netting over fruit trees.

Steve, hey that plastic sounds damn cheap, I think I know the stuff you mean, as I have seen something similar at bunnings, however it was rather expensive there for memory...

Would you design some form of opening vents into your greenhouse for summertime?

Joel,

The price is very cheap! i had trouble tripping over the words "gimme the supplier!" when i heard what the guy had paid

Yes will be putting in two vents to start with one end with a grond level vent and the other end with a roof level vent. i plan to have these open (a little) even in witner as CO2 (and hence plant growth) is used up very quickly when the big light in the sky is turned on. the winter months will give me some time to organise an axial fan in the end wall for summer (all the poly tunnels and my friends nursery had them for summer).

i hope to have this organised in the next 2 weeks. i'm sick of talking about this and sitting on my perch **excuse the pun** while everyone else is actually building thier systems

On a more positive note i received my "sunbeam mincer" that i bought off the internet today i can see myself stinking up the house tonight making home made fish food.

I know what you mean about the perch not feeding well in low temps. I think it becomes really noticable below about 18C.

While i'm talking about fish food does anyone know if it would be better using raw fish or cooked. i'm assuming raw, as thats the way the fish would normally eat just thought that by cooking it the storage life might be extended. comments welcome

steve

Had thought of something like you describe Joel, but am concerned that there may not be enough sun right near the shed. Unless I decide to cut some of my trees down to let the sun through better, will probably have to move away from the shed a bit and just have th pipes a bit longer running into and back from te shed. Will watch the sun over the next couple of days in that area to see what my prospects are. In the past I have always used this area by the shed for my pumpkins, have 40-50 there at the moment. Will mis using the area for this, but I'm sure I can find somewhere else for them.

Joel, you mentionned in your book that the lazerlight stuff on your roof was somewhat cheaper than the stuff you can buy at bunnings (it is expensive as anything there). How much did you pay, and does the product have a name?

Ahhhhh Steve, the thought of fish being cooked up and going through the mincer, stinking out the house as you get your hands into it all mixing and mashing it up..... Excuse me if I.... I guess your girl must be out for the night if your thinking of doing that....

Did those earlier links on fish feed making give any hints as to whether the fish should be cooked or not?? Personally I like the idea of going for the recipe using wheat/sprouted wheat etc, not quite as smelly or gross to deal with....

VB, roughly how far are you looking at running the pipework from shed to greenhouse then? I'm just thinking of loses in flow from long pipe lengths that's all... I guess the beauty about a lean-to style greenhouse (if of course it's possible with aspect, light etc) is that there's one wall already there to build out from...

The lazerlight, for memory was maybe $20 a sheet...? I don't remember exactly.. I hired a guy to help me build my pergola/greenhouse thing and he organised the materials. I remember him being very happy that not only had he found a local manufacturer (helping a small business) but it was about half the price of the 'named' stuff. Might be best if you have a look through the yellow pages for plastics manufacturers/roof sheeting etc, and make a few phone calls in your local area VB might save a lot of money... Thats assuming that you decide to go that way of course...

Joel - I'm only talking 5 or so metres (definitelly no more than 10) from tank to grow beds. I will most likely use a single sump pump - water pumped from tank to beds and thn gravity flow straight back to the tank (through piping of course). I already have a Davey Vortex D15VA-1 sump pump that I bought for my grey water sump. but didn't end up using because I had an older sump pump stashed away that still works. It pumps 140 litres per minute and has a maximum head of 7 metres. This should be more than sufficient. My only concerns with this pump are:

- it is not the type with the stainless stell strainer fitted to the bottom. It is the tupe with the 4 legs. Gravel could theoretically get into this pump - but there are plenty of measures that I can probably take to avoid this. I also hope that the fish would be smart enough not to get sucked onto the pump.

- These pumps have th mechanicals sealed in an oil bath. I note that the fish pond type pumps sold by say Davey are marketted on the basis that there is no oil and therefore will not harm the fish. I pressume oil would only leak from my pump if it wore in some way and was effectivelly broken.

After much searching I purchased a kit greenhouse from Rion. Its made of plastic and hopefully will not be a waste of funds. Trying to justify the cost in so many ways. In the begginning the aquaponics will take up only a third to a half of the area. This way my better half can use it also for her flowers. The justifications can go on and on can't they? Worried about heat retention in the winter I'll place 2" (5cm) certifoam on the ground and have a pea gravel floor of 9 1/2" (24cm) over that. Hoping for some thermal mass here. The fish tank will be inground and the hole also lined with certifoam. The tank a rubbermaid 300gal roughly 1000liters? I may be going overboard but I'm also considering some type of floor heating, some water pipe running thru not sure yet. I have zero experience with green houses but its a must in my area if I want any kind of system outside. This will be a test system? A few pic's of present progress.

Is the black stuff some kind of liner?

Steve, its a layer of "weed matting" i guess its called, not plastic more of a cloth weave.

Far North NZ they leave greenhouses fallow in the hottest two months. I know 300 miles South of that we'd grow all year round in them.

Shade paint is an option for Summer housing, as is shade cloth, just use the green, not black.

Windows - though automated gables sound lovely etc, if you are checking your fish each day you'll be out there anyway.

Save the automation for when your Aqua is now consuming your 'quality' time with others, that's when it's worth it.

Thermal stability. Ponds in the ground, stone floor, brick or stone back wall if you can get away with it. I had no room to come straight off my brick home, or I would have.

On prices - I got a 50x20 quote - $87 000 plus GST. I can build a much better looking wooden double skinned with plastic the same size for $30 000. But! My price does not include labour (add $17 000).

I've made an incredibly light yet strong and see though door, I must borrow that bloody camera.

Windows - still trying to design similar to door, light strong and see through.

Insects! In an enclosed environment with reasonably high humidity several insects are given the prime conditions to explode. Mites, fungus gnats, thrip and many others will love your greenhouse. It is impossible to keep all the insects out but here's a few tips.

Don't work in the outside garden then go to the greenhouse.
Shoes off at the door.
Insect screen doors and gables.
Insect screen will restrict airflow by 66%. Bear this in mind if planning to use ventilation via screens. More is better.
When you find ladybirds spiders and praying mantis put them in your greenhouse. The praying mantis will kill and eat your ladybirds and spiders eventually but will go for the 'vegetarians' first.

And - DON'T smoke in your greenhouse. Clean your hands before entering if you are a smoker. Tomatoes and some other plants are susceptible to tobacco mosaic virus and once they have it you can't get rid of it short of pulling out the entire crop and starting again.

Look for resistant varieties. I once had 2 cucumbers. Same plot. One grew a fantastic crop. The other grew powdery mildew. I know which one I'm still using....

A few thoughts on greenhouses:

- sun-facing greehouses are simple and cost effective to make. They look like a simple lean-to shed. If they can be mounted against a brick or masonry wall so much the better.
- a cheap greenhouse can be made from reinforcing mesh (the stuff they use in concrete slabs). It is bent into a sem-circle and secured using steel pegs. Plastic sheet is secured over the mesh and tied into the the one end. A doorway is fitted into the other end.
- the greater the mass that can be accommodated in a greenhouse (concrete, bricks, stone and especially water), the more even the temperature control.

The smaller the greenhouse the cheaper it gets (obviously) so:
- consider a greenhouse that has no passageways in it - you operate it from outside of the structure. In Singapore (among the leading hydroponics/aquaculture/aquaponics nations in the world), these small greenhouses are very common - particularly on roof-tops where space is at a premium.
- consider a pit greenhouse - they are particularly efficient.

I found a drawing of a pit greenhouse. If you want the most cost effective and energy efficient greenhouse, you should consider one of these.

OMG and I've only got a spade....

I love lean to's so simple to make but I couldn't...

That is a cool pithouse, it would unfortunately also be underwater in some locations.

Especially water?!! It's that good at thermal stability? EXCELLENT!

Great to see you getting head first into it GOtfish. Can't wait to see it up and running. Are your frames plastic? If so, how rigid are they?

Stu