zebula
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Posts: 3
Joined: Tue Nov 01, 2016 11:06 am

Health problem with pak choy

Hi there, I am doing some experiments for my research project and I need to grow hydroponically some Pak Choy. I

used 1/2 strengh Hoaglands solution in a 7 Litres tray. I aerate through air coming from inlet and I have pH around 6.3 as recommended. Problem is that the plants are not surviving.

I first germinated the plants in Vermiculite and then rinsed the roots and put them into the tray . 6 plants for 7 Litres trays. The pH changes very much and I needed to adjust first with around 6mL 1M KOH and then adjust the next days with quite a lot of H2SO4 to maintain pH 6.3-6.5 I use UV light around 8 hours a day to provide them light.


Problem is
1) they still die. And by dying they actually shrink and the stem becomes weak and then the whole plant dies. In the same time the leaves shrink and retract themselves.

2) Some yellow things are growing in the water, it seems like an algae is growing, is that a problem? I am very annoyed because it seems my setting was quite good and now it just doesnt work... My plan was to change the water every week but none of the plants made it so far...

Thanks for any recommendation or help
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leaves dying
leaves dying

imafan26
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Joined: Tue Jan 01, 2013 8:32 am
Location: hawaii, zone 12a 587 ft elev.

Re: Health problem with pak choy

Instead of a raft can you use a rail or tower for the project. Bok choy is like chard, it is top heavy and needs to have a lot of aeration. In a floating raft system you may not be getting enough with your aerator. We did have success growing similar plants chard and kale in rafts and towers because the water runs over the roots and they are not constantly submerged. The plants were also easier to keep upright. The other thing you could do is instead of a raft system, grow them in a dutch bucket instead with cinder or hydroton.

https://www.uky.edu/Ag/CCD/brassicamq_tw.htm
Happy gardening in Hawaii. Gardens are where people grow.

zebula
Newly Registered
Posts: 3
Joined: Tue Nov 01, 2016 11:06 am

Re: Health problem with pak choy

Thanks for the reply!

I needed to have the roots submerged and to not have other things in contact with water because I am looking at the uptake of contmainants by plants and therefore I don't want to introduce thing that could absorb or adsorb the contaminants.

There is actually a gap between the raft and the water that is quite big and allows to have still air ( the roots are then not entirely in the water)The aerator is actually a tube linked to an air outlet of the fumehood: The tube has many holes to have even aeration of the media.

Did you transplant at the 4th leave or did you do it at the second one? Because I did not wait until the 4th leave because I was afraid the plant would not get enough nutrients to survive because I grow them initially in vermiculite...



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