hydro/aquaponic gardening

[Math52]

Hello everyone,

I am planning to start a hydroponics project to grow lettuces on a 3000 sqm land located in Nontaburi. I've chosen lettuce because it is said to be the easiest way to get into hydroponics. So, I don't know exactly where to start but I guess building a greenhouse is the first step. And I have to say, this very first step already brings a lot of questions. About the material, I have been visiting many hydroponics farms and I have seen all kinds like aluminium, bamboo, PVC.. And also a lot of different shapes. Could someone advise me on the best greenhouse setting if I plan to grow my lettuce in horizontal gutters ? I have seen some farms where everything is wide open on the side and there is only a 60% shade 2m50 above the ground... How does it protect the lettuce from the bugs or the birds or whatever could damage the lettuce ?

By the way, I have chosen horizontal gutters because I believe this is a good way to bring oxygen to the lettuce (especially under warm climate, I understand it is difficult to bring oxygen to the lettuce above 30 degree celcius). If you consider other options are equivalent or better and cheaper or easier to maintain please don't hesitate to tell me.

Another point I would like to clarify is about the need for a greenhouse in Thailand : what is exactly the purpose of a greenhouse ? Of course it protects from the rain, from the bugs I guess but since the humidity here is already above 60% all year long, is there room to balance higher temp with higher humidity levels ? Or will this problem (high temp) can be solved only with pulverisation of bore and calcium on the crop ?

As you can see, I don't know anything about hydroponics. I was planning to build a PVC greenhouse and start my experiments to see what works best then I could duplicate with other greenhouse but the type of greenhouse I should use at first is already raising many questions.

I hope this post will give me some answers. In the meantime, I will keep reading this very interesting thread.

Math

 

 

[Time to grow]

On 5/28/2020 at 1:54 PM, carlyai said:

Will make a concrete enclosure like yours.

A problem is developing that I wanted to pass on. I built a sump identical to this one on higher ground without a problem. Now that we are starting to get some rain, this new sump seems to be weeping ground water through the sump walls.

 

I am not 100% certain this is whats happening but I can't find another source. If the ground water is seeping through the walls, I cringe at what the fix might look like. Any creative ideas would be appreciated.

 

On a happy note, we have had water circulating for a week or so now. I plan to let the bacteria get established for another couple weeks before adding Tilapia and seedlings. In the meantime, I will be working on getting the screen assembled and installed over the screen house.

[Time to grow]

On 6/7/2020 at 5:27 PM, Math52 said:

the type of greenhouse I should use at first is already raising many questions.

I know nothing about hydroponics but have a little experience with aquaponics.

 

I started out with a PVC structure, kind of a reinforced hoop house, and fine mesh nylon screen for my "green house". It's not really a "greenhouse" but a screen-house to keep out the bugs, blowing leaves, and other unwanted critters.

 

I found that even with careful design afforded to the structure, PVC is no match for the intense sun and occasional squall. I have now gone to welded steel tube. I drew up what I wanted and had a local welder bend and weld to my specifications. It was surprisingly inexpensive and much more sturdy. I expect this latest design to work for many years.

[Math52]

18 hours ago, Time to grow said:

I found that even with careful design afforded to the structure, PVC is no match for the intense sun and occasional squall. I have now gone to welded steel tube. I drew up what I wanted and had a local welder bend and weld to my specifications. It was surprisingly inexpensive and much more sturdy. I expect this latest design to work for many years.

Hello TTG. Thank you for your feed back! Since my last post, I visited other farms and also concluded that PVC doesn't fit my needs. Not strong enough. About the inexpensive steel tubes, I didn't check for the prices yet. Are these galvanized steel pipes ? Should they be pipes ? Or squared is easier to work on and also cheaper ?

Thank you!

[Time to grow]

4 hours ago, Math52 said:

Are these galvanized steel pipes ? Should they be pipes ? Or squared is easier to work on and also cheaper ?

Math52,

 

I used galvanized steel pipe, a combination of 1.25" and 1.5" for this 6 meter by 25 meter structure but square tube might be superior for one reason or another. You can see pictures on page 14 of this thread. Labor and materials for the top horizontal portions cost me 43,000 THB for a local welder to fabricate the arches. The vertical side posts were separate. I dug holes and set the 1.25" verticals in concrete, then had the welder fabricate the horizontal segments from 1.5" galvanized steel pipe. This way, I simply dropped the horizontal arches down on top of the vertical posts. Then had a neighbor weld segmented ridge beams and a continuous top plate on the sides. Finally, I used galvanized square tubing all the way around as a base plate. This was intended to contain the gravel floor and provide an anchor for the nylon mesh.

 

If you happen past Nakhon Sawan area, swing by. I would be happy to show you around.

[stament]

Interested in visiting a set-up in the Chiang Mai area if possible.

 

Thanks

[Math52]

20 hours ago, Time to grow said:

Math52,

 

I used galvanized steel pipe, a combination of 1.25" and 1.5" for this 6 meter by 25 meter structure but square tube might be superior for one reason or another. You can see pictures on page 14 of this thread. Labor and materials for the top horizontal portions cost me 43,000 THB for a local welder to fabricate the arches. The vertical side posts were separate. I dug holes and set the 1.25" verticals in concrete, then had the welder fabricate the horizontal segments from 1.5" galvanized steel pipe. This way, I simply dropped the horizontal arches down on top of the vertical posts. Then had a neighbor weld segmented ridge beams and a continuous top plate on the sides. Finally, I used galvanized square tubing all the way around as a base plate. This was intended to contain the gravel floor and provide an anchor for the nylon mesh.

 

If you happen past Nakhon Sawan area, swing by. I would be happy to show you around.

Thank you TTG,

Very impressive the work you've done ! For growing lettuce in Thailand though I don't think I'll need this kind of greenhouse. I have been visiting a lot of hydroponic farms and apparently smaller metallic structure just above the crop to support a shade is enough. Farmers, here, don't even put plastic to protect the crop from the rain (except for seedlings). From what I understand, the most important is to pulverize water on the crop when the temp is increasing and keep the water temperature as close as possible to 31 degre celcius.

I'll definitly pass by your spot when I'll have the opportunity. I am curious about aquaponics. 

Have a good day ????

Math

[carlyai]

5 minutes ago, Math52 said:

Thank you TTG,

Very impressive the work you've done ! For growing lettuce in Thailand though I don't think I'll need this kind of greenhouse. I have been visiting a lot of hydroponic farms and apparently smaller metallic structure just above the crop to support a shade is enough. Farmers, here, don't even put plastic to protect the crop from the rain (except for seedlings). From what I understand, the most important is to pulverize water on the crop when the temp is increasing and keep the water temperature as close as possible to 31 degre celcius.

I'll definitly pass by your spot when I'll have the opportunity. I am curious about aquaponics. 

Have a good day ????

Math

 

[Math52]

4 minutes ago, carlyai said:

 

Hello Carlyai, what is that for please ?

[carlyai]

24 minutes ago, Math52 said:

Hello Carlyai, what is that for please ?

Hi Math52   sorry something is going wrong with my posting today. That was for TTG about ground water into the sump.

I just posted one for you about the green house but don't think that has gone as well. I'll wait and see if it all sorts itself out. ????

[Time to grow]

1 hour ago, Math52 said:

support a shade is enough. Farmers, here, don't even put plastic to protect the crop from the rain (except for seedlings).

That's true but most farmers the world over, don't have any issues with using herbicides and pesticides to control bug pressure. My primary objective is to grow healthy organic food. Otherwise, it would be much more efficient to simply purchase vegetables at the market. A screen enclosure significantly decreases bug pressure. I am not a trained farmer but it seems like a common sense solution to me. Rain damage is minimized as well but this is not really a concern of mine. Best of luck in you endeavor.

[Time to grow]

Carlyai,

 

Thanks for the solution. I wonder if that will work if applied to the interior of the concrete sump? I think it's designed to be applied to the wet side of the wall or subsurface as the case may be.

 

Short of removing the existing concrete sump and doing it correctly, I guess I don't have much choice but to try it.

[stament]

On 6/12/2020 at 2:56 PM, Time to grow said:

I know nothing about hydroponics but have a little experience with aquaponics.

 

I started out with a PVC structure, kind of a reinforced hoop house, and fine mesh nylon screen for my "green house". It's not really a "greenhouse" but a screen-house to keep out the bugs, blowing leaves, and other unwanted critters.

 

I found that even with careful design afforded to the structure, PVC is no match for the intense sun and occasional squall. I have now gone to welded steel tube. I drew up what I wanted and had a local welder bend and weld to my specifications. It was surprisingly inexpensive and much more sturdy. I expect this latest design to work for many years.

What are you growing, what grows well? Any photos of your greenhouse please?

[Time to grow]

6 minutes ago, stament said:

What are you growing, what grows well? Any photos of your greenhouse please?

I am growing all kinds of things but mostly leafy greens. There are pictures of my existing greenhouse on page 13 of this thread and pictures of my new greenhouse on page 14.

[stament]

On 2/25/2019 at 10:10 PM, user343434 said:

Hi rice555,

 

funny, without knowing that guy I went the same way, bought a dozen of these white buckets at Home Pro, connected them with PE pipes and found out the hard way: without a cooled greenhouse dutch buckets won't work or at least the yield is way too small in our hot climate.

I kicked the whole system and focused more on "cool feet" of the plants using ebb flood grow beds.

My new redesigned system is almost complete and pics will follow soon here.

 

 

Confused now I thought people in Thailand were growing tomatoes successfully using the Dutch bucket system? 

[carlyai]

19 hours ago, Time to grow said:

Carlyai,

 

Thanks for the solution. I wonder if that will work if applied to the interior of the concrete sump? I think it's designed to be applied to the wet side of the wall or subsurface as the case may be.

 

Short of removing the existing concrete sump and doing it correctly, I guess I don't have much choice but to try it.

It's a bit of a b.... to apply, and you need a mask. You may not need to render after applying it in your case as the mix won't touch your water. 

[carlyai]

@math53    What I posted yesterday about the greenhouse didn't post so will try again. I'll get the pics in first incase something stuffs up.

[carlyai]

I saw some melon greenhouses and asked the owner to have a look at my place and his team built my 12 x 4 m greenhouse for B16000. I had never seen the dipped metalwork before but it makes a nice rust proof job. The roof is plastic and lasted about a year already. The sides are like insect screen. All strong and has withstood strong winds and Isaan rain and sun.

I wanted shade cloth on top but they put it outside the plastic and it blew away. I saw a fully automated greenhouse at an ag show and the greenhouse had c channel along the horizontal top metal where the shade cloth ran along like a curtain. So you could pull the shade cloth along to cover a section if you want. 

When the wind blows horizontally the rain still gets in. There could have been a couple of more semicircular roof supports as the plastic sags.

I made the GH tall as I want to add Dutch Buckets and grow melons etc up a string line. Robert from Thailand Aquaponics is experimenting with a style of Dutch Bucket with small computer fans built in to airate the roots. He's got a pretty neat set up and I should be in Banggers next week and try and pick one up to try. Just gotta finish all these half finished pesky fiddly jobs then back into the aquaponics.

[stament]

9 minutes ago, carlyai said:

I saw some melon greenhouses and asked the owner to have a look at my place and his team built my 12 x 4 m greenhouse for B16000. I had never seen the dipped metalwork before but it makes a nice rust proof job. The roof is plastic and lasted about a year already. The sides are like insect screen. All strong and has withstood strong winds and Isaan rain and sun.

I wanted shade cloth on top but they put it outside the plastic and it blew away. I saw a fully automated greenhouse at an ag show and the greenhouse had c channel along the horizontal top metal where the shade cloth ran along like a curtain. So you could pull the shade cloth along to cover a section if you want. 

When the wind blows horizontally the rain still gets in. There could have been a couple of more semicircular roof supports as the plastic sags.

I made the GH tall as I want to add Dutch Buckets and grow melons etc up a string line. Robert from Thailand Aquaponics is experimenting with a style of Dutch Bucket with small computer fans built in to airate the roots. He's got a pretty neat set up and I should be in Banggers next week and try and pick one up to try. Just gotta finish all these half finished pesky fiddly jobs then back into the aquaponics.

Is the greenhouse a necessity? Would shade clothwork if using a DWC rather than pipe system?

[carlyai]

2 hours ago, stament said:

Is the greenhouse a necessity? Would shade clothwork if using a DWC rather than pipe system?

I think bugs are going to be a problem if the vegetables etc are not enclosed. Then you might have to spray for the bugs. There's no reason to start with a greenhouse, you can add one later if needed. I think TTG didn't have a greenhouse when he started and he's done great.

DWC seems OK for hydroponics, but I'm not sure about aquaponics. 

[Math52]

On 6/14/2020 at 12:01 PM, Time to grow said:

That's true but most farmers the world over, don't have any issues with using herbicides and pesticides to control bug pressure. My primary objective is to grow healthy organic food. Otherwise, it would be much more efficient to simply purchase vegetables at the market. A screen enclosure significantly decreases bug pressure. I am not a trained farmer but it seems like a common sense solution to me. Rain damage is minimized as well but this is not really a concern of mine. Best of luck in you endeavor.

Yes, you are right I guess. What is a screen enclosure ? Do you think a 8x3m greenhouse can be done with PVC ? Will it be strong enough ?

[Time to grow]

46 minutes ago, Math52 said:

Yes, you are right I guess. What is a screen enclosure ? Do you think a 8x3m greenhouse can be done with PVC ? Will it be strong enough ?

A screen enclosure is a greenhouse like structure (see the photos), covered in a fine nylon mesh instead of sheet plastic. A screen house does not regulate the weather (i.e., air temperature, relative humidity, vapor pressure deficit, and or CO2 concentration) like a greenhouse is intended to do. It's purpose is to reduce insect & vermin pressure. I have tried a couple different designs from PVC that all met in failure eventually. You might have more moderate weather where you live or might be better at engineering than I am but I wont be building with PVC anymore. Will PVC be strong enough; is a difficult question to answer, similar to, "How long is a string?".

[stament]

What are people using in their growbeds besides the clayballs? I don't want the expense of that to start with and I read gravel if tested ok is used but is it a specific sort? And also Coco husks.

[carlyai]

30 minutes ago, stament said:

What are people using in their growbeds besides the clayballs? I don't want the expense of that to start with and I read gravel if tested ok is used but is it a specific sort? And also Coco husks.

If you go with a raft system then you don't need the clay balls. I have seen a couple of DWC or raft systems and it seemed to me that the vegetables nearer the water entrance were the greenest and those at the water exit the poorest. That was just my impression, but many people use DWC systems successfully. 

I went for the clay balls because, if you buy good ones they are supposed to last forever. They have a large surface area that is great for growing bacteria. If you use rocks as a media you need to make sure that no minerals are leaching out of the rocks. People do use rocks and other media.

I'd follow what Time to grow is doing because he's done it already where I have only mainly read about it. 

So you need to look at your objective for having an aquaponic setup. My objective is to have fresh fish and vegetables with no chemicals and minimum maintenance. 

[Math52]

5 hours ago, Time to grow said:

A screen enclosure is a greenhouse like structure (see the photos), covered in a fine nylon mesh instead of sheet plastic. A screen house does not regulate the weather (i.e., air temperature, relative humidity, vapor pressure deficit, and or CO2 concentration) like a greenhouse is intended to do. It's purpose is to reduce insect & vermin pressure. I have tried a couple different designs from PVC that all met in failure eventually. You might have more moderate weather where you live or might be better at engineering than I am but I wont be building with PVC anymore. Will PVC be strong enough; is a difficult question to answer, similar to, "How long is a string?".

Thank you for this explanation! When you talk about "moderate weather", you mean less wind right ? The different designs you tried from PVC collapsed because of the wind ? I believe the size of the greenhouse I have in mind in much smaller than yours : 3m large x 8 m long and 2,50 height. And yes, probably less wind in the middle of Nontaburri than in your area. I'll give it a try and let you know.

Also, you're saying the screen enclosure is a greenhouse like structure covered in a fine nylon mesh instead of sheet plastic. It doesn't include the roof part right ? All around it should be nylon mesh but sheet plastic on top of the structure ?

By the way, do you know why hydroponic Thai farmers prefer to use pesticides instead of screen enclosure ? Is it a question of price (cheaper to use pesticides) or a problem of maintenance then also price ? 

Edited June 15, 2020 by Math52

[Time to grow]

31 minutes ago, Math52 said:

you mean less wind right ?

Yes, the wind seems to be the most destructive but don't ignore the intense heat that softens the PVC and UV radiation that breaks it down. The wind resistance using mesh is much lower than would be realized from sheet plastic or even woven shade cloth. In other words, wind will be more of a factor with a more solid covering.

 

I cover the entire structure in Nylon mesh, the sides, the ends, and the top. Then I hang shade cloth on the interior where necessary. I do not use solid sheet plastic at all. This is not necessarily the best way, it's just the method that has worked best for me.

 

40 minutes ago, Math52 said:

farmers prefer to use pesticides instead of screen enclosure ?

 

I think farmers the world over are generally sold a solution to bug pressure by Big Agra. A solution that provides a revenue stream for the conglomerates without regard for the health of the product or the environment. Economics may be a factor as well but I would imagine this is a short sighted approach. I haven't done a price comparison but the cost associated with the health of my family would be pretty high when comparing.

[Time to grow]

3 hours ago, stament said:

What are people using in their growbeds besides the clayballs?

Like you, I wasn't prepared to spend a fortune on the media either. I found a local source of river rock initially that I tried. I tested it for pH change and none was detected. I filled all my raised beds with the river rock. After about a month I noticed a pH issue developing where the pH was continually rising.

 

I considered the problem could be from the concrete structure of my DWC, from the river rocks, or the pH of my source water changing. My source water is a hand dug well on site.

 

I attempted to resolve the pH issue by lining the DWC with a pond liner, adding several logs to the DWC to help buffer the water, and finally biting the bullet and replacing the river rock with Hydroton (clay balls). The Hydroton was a considerable expense but I found a reasonably good price from a hydroponic farmer in the Bangkok area.

 

After making all these changes, the water still continued to increase in pH over time. It does so to this day and I don't know the cause. I now add small amounts of Hydrochloric Acid periodically to lower the pH as necessary.

 

That being said, I am very happy I replaced the river rock with Hydroton simply because it's so nice to work with. After I harvest a media bed, I take out all the Hydroton and rinse it off to remove the solid waste that gets past my filters. The Hydroton is so light and easy on your hands compared to the river rock, this job of cleaning is a breeze. If I were making more media beds, I would definitely use Hydroton again.

 

I have heard of others using coco fibers but I have no experience with it. I would think the coco fibers would break down too quickly but apparently others are making it work for them.

[stament]

On 6/15/2020 at 10:19 PM, Math52 said:

Thank you for this explanation! When you talk about "moderate weather", you mean less wind right ? The different designs you tried from PVC collapsed because of the wind ? I believe the size of the greenhouse I have in mind in much smaller than yours : 3m large x 8 m long and 2,50 height. And yes, probably less wind in the middle of Nontaburri than in your area. I'll give it a try and let you know.

Also, you're saying the screen enclosure is a greenhouse like structure covered in a fine nylon mesh instead of sheet plastic. It doesn't include the roof part right ? All around it should be nylon mesh but sheet plastic on top of the structure ?

By the way, do you know why hydroponic Thai farmers prefer to use pesticides instead of screen enclosure ? Is it a question of price (cheaper to use pesticides) or a problem of maintenance then also price ? 

Have you decided on your greenhouse build yet? I'm about to start one so am thinking what's the best approach whilst trying to keep costs down.

 

Will the green screening keep bugs away, some people I spoke to have their doubts so maybe full ceiling to floor plastic sheeting is required.

 

Any thoughts from members experienced in this.

 

Thanks

[carlyai]

41 minutes ago, stament said:

Have you decided on your greenhouse build yet? I'm about to start one so am thinking what's the best approach whilst trying to keep costs down.

 

Will the green screening keep bugs away, some people I spoke to have their doubts so maybe full ceiling to floor plastic sheeting is required.

 

Any thoughts from members experienced in this.

 

Thanks

@stament not sure if you have read what TTG and I have posted. If you look at the pics of my greenhouse you will see it has a plastic roof and insect screen fabric for the walls. I think TTG just has insect screen all over. It's strong stuff and no bugs are getting through it.

The green shade cloth will not last. The plastic roofs have to be replaced about every 2 years I was told.

[stament]

3 hours ago, carlyai said:

@stament not sure if you have read what TTG and I have posted. If you look at the pics of my greenhouse you will see it has a plastic roof and insect screen fabric for the walls. I think TTG just has insect screen all over. It's strong stuff and no bugs are getting through it.

The green shade cloth will not last. The plastic roofs have to be replaced about every 2 years I was told.

Sorry, my error. I misunderstood. I intend to use shade cloth as a cheap option to start with along the sides and roof. Not sure if I will use green or black shade cloth. I've spoken to people who say black and some say green lol. My concern with black is will enough sun come through for the plants to grow.

 

What are your and TTG's thoughts on this?

 

Thanks