Math52

On 11/28/2015 at 11:18 PM, rice555 said:

Hello All, SJS I've been looking at this place to get my roof pieces, they also have wider ones, I go

by this place and a fab shop shop that can bend 6" pipe to and from downtown Korat.

There are several adds in the Thai Ag Magazines for poly coverings and insect netting, and wiggle

wire, you can find snap channel if you look hard.

rice555

Hello All, Hi Rice555,

This is an old post from hydroponics thread from page 23 or 24 (out of 32 pages) which show some places where they sell ready made roof for GH. Do you know where to find the same places here in Bangkok where I can buy the roof part of my future GH. Bongsai Agro is selling their own (second hand) for 25.000 THB (everything included) but I beleive I can reduce the cost by 20% if I can do it by myself and it will also be brand new.

Thank you

Math52

On 3/7/2017 at 10:41 PM, Hereinthailand said:

Some Interesting reading

How do I manage EC.docx

Preparing Your Own Hydroponic Nutrients.docx

How do I manage acid addition and pH rise.docx

What acid should I use for pH control.docx

There are five things you need to understand before.docx

The Big Five.docx

Hello HIT, hello everyone,

These readings are very interesting indeed ! I was surprised to find out that (according to these articles) NFT, the system that is mostly used in Thailand for growing lettuce is said to be not appropriate for tropical/hot climate... Apparently it requires a high level of control of the environment. To my understanding it can be use in Greenhouse provided that you have all the ventilation system up and running which, once again, is rarely the case in Thailand. Any idea why people are using it anyway ?

Thank you!

Math52

On 6/17/2020 at 4:09 PM, 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

That's the plan ! You can check this on their website (http://www.bangsaiagro.com/aboutus#visit_farm) or visit them directly to have a better idea. They are using DRFT instead of NFT which doesn't matter much to my opinion. Main advantage is the plants will survive in case of electricity shortage. With this setting, you can access your plants from both sides.

I didn't start the construction yet. Need to buy a bending tool for the steel pipe. The length of this "wagon" is 6 meter, plastic on the top + insect screen on the sides. I like the concept. I think it is even possible to optimize if you replace the DRFT with vertical NFT (not vertical in fact but upside down V shape). 

About insect screen, the people at this address admitted that even with the screen, some bugs can go through so they need to use pesticides times to times. That's really a problem because you cannot advertise as pesticide free if you use some even if it is not much.

Let me know what do you think about this. 

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 ? 

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 ?

4 minutes ago, carlyai said:

 

Hello Carlyai, what is that for please ?

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

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!

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