Dwc water level?

Quick question about dwc...is the water lvl supposed to be 2 inches below my netpot or are the bottom two inches of the net pot supposed to be submerged?

Water below net pot

Water should be touching the net pots until roots poke through. Then 1-3 inches below the nets to allow the exposed roots to take in the needed o2.

I was taught that between 20% to 40% of the root mass should be out of the water & that is how i run my dwc system,keep in mind that my dwc system is not my main system which is flood & drain so my info may be inacurate for best results.

I was taught to keep the water 2 inches below the net pot until the roots explode from hitting the water,then adjust air space depending on how much root mass is below water.

The plant gets like 1% of the oxygen it needs from DO in the water. The rest comes from the hanging roots. You simply can't get enough o2 into the water. There is a DO limit. The vast majority of the root mass is below the water level.

Cheers my friend, that makes perfect sense... thanks for clearing that up.

The reason you want the bottom of the pot at 2" is so it can stay moist enough,the bubbles in the water pop & help keep it moist enough,along with the humidity in the area between the water & lid,any farther & you risk having the pot dry up.

Ive only been doing dwc for about a year now & on a small scale but what i posted works for me,so far,anybody have better info i'd be glad to hear it cause im far from a dwc master.

The reason you want the bottom of the pot at 2" is so it can stay moist enough,the bubbles in the water pop & help keep it moist enough,along with the humidity in the area between the water & lid,any farther & you risk having the pot dry up.

Ive only been doing dwc for about a year now & on a small scale but what i posted works for me,so far,anybody have better info i'd be glad to hear it cause im far from a dwc master.

Man I see this question pop up at least once a month.. maybe twice. Answers range from inches below the net pot to slightly above it. Mine is kept at the bottom of the net pot, right below the rockwool. They drink more that way.

BendBrewer said:

The plant gets like 1% of the oxygen it needs from DO in the water. The rest comes from the hanging roots. You simply can't get enough o2 into the water. There is a DO limit. The vast majority of the root mass is below the water level.

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Sort of on the right track but your numbers are off. You can have too much DO in the water for plants. Now you need some very expensave equipment to do that but you can have to much DO in water. You and me will never have to worry about it.

[FONT=&quot]http://www.uoguelph.ca/research/apps/news/pub/article.cfm?id=90[/FONT]

[FONT=&quot]Higher dissolved oxygen great for productivity, health and vigor[/FONT]
[FONT=&quot]Research[/FONT] [FONT=&quot] > [/FONT][FONT=&quot]Learn About Research[/FONT][FONT=&quot] > [/FONT][FONT=&quot]News[/FONT][FONT=&quot] > Higher dissolved oxygen great for productivity, health and vigor [/FONT]
[FONT=&quot]By Robert Fieldhouse
(Guelph, October 13, 2005)[/FONT]
[FONT=&quot]Dissolving more oxygen into hydroponic solutions could boost greenhouse productivity and provide a whole host of other benefits too, say University of Guelph researchers.[/FONT]
[FONT=&quot]Prof. Mike Dixon and Dr. Youbin Zheng, Department of Environmental Biology, are investigating the positive aspects of using an oxygen diffuser to increase oxygen levels in greenhouse hydroponic solutions used to grow roses, tomatoes, cucumbers and peppers. [/FONT]
[FONT=&quot]

[/FONT]
[FONT=&quot]Dr. Youbin Zheng, Department of Environmental Biology, is studying if oxygen levels can be boosted in hydroponic solutions to help growers ward off harmful microbes and boost productivity. [/FONT]
[FONT=&quot]
Photo credit: Olivia Brown [/FONT]
[FONT=&quot]Preliminary results suggest a higher dissolved oxygen level increase productivity, health and root vigor in greenhouse plants, and helps keep harmful microbes in check.[/FONT]
[FONT=&quot]“These findings are really beneficial to the industry,” says Zheng. “If we can use oxygen to boost plant health, making them stronger and more resistant to disease, we've discovered a very helpful tool.”[/FONT]
[FONT=&quot]Oxygen isn't as prevalent in warm water as in cool water, so oxygen levels tend to be low -- about two to four parts per million (ppm) -- at high greenhouse temperatures, compared to eight to nine ppm in cool water. Under hot weather in the greenhouse, the root zone is especially short on oxygen, says Zheng, because root respiration depletes oxygen in hydroponic solutions. Excessive watering can further depress oxygen levels because it makes growth media, such as rockwool or coconut fibre, less porous, blocking air. These factors all weaken plant disease defense systems, making them more susceptible to disease-causing microbes such as Fusarium and Pythium which cause root decay.[/FONT]
[FONT=&quot]To prevent this problem, greenhouse growers typically bubble air into hydroponic solutions to bring oxygen levels up to about nine ppm. But sometimes this still isn't enough.[/FONT]
[FONT=&quot]Two years ago, the BC Greenhouse Growers' Association asked Dixon to investigate using even higher oxygen levels in hydroponic solutions. His literature review revealed that very little work had been done in this area suggesting the problem was largely ignored – until now.[/FONT]
[FONT=&quot]Dixon and Zheng are using an oxygen diffuser recently developed and manufactured by Seair Diffusion Systems Inc., an Edmonton-based company with an interest in the greenhouse sector. The diffuser concentrates atmospheric oxygen, and dissolves it into hydroponic solutions. With this technology, oxygen levels can reach as high as 60 ppm in hydroponic solutions.[/FONT]
[FONT=&quot]The research team is currently studying the effects of different oxygen levels, ranging from about nine ppm to 40 ppm.[/FONT]
[FONT=&quot]So far, preliminary results are promising. But creating optimal supersaturated oxygen solutions requires extreme precision. Oxygen can be damaging at very high levels, says Dixon , so it's important to establish application methods for using this technology for different crops.[/FONT]
[FONT=&quot]But if the methods can be worked out, Dixon says the oxygen diffusers are inexpensive and stand to emerge as an economical, environmentally friendly solution for growers looking to enhance their crops.[/FONT]
[FONT=&quot]“Greenhouse growers are voracious technical consumers – they'll try anything,” says Dixon . “But by the same token, they're also very shrewd business people, and they won't waste money unnecessarily.”[/FONT]
[FONT=&quot]Dixon and Zheng will continue their research and will further investigate oxygen's effect on plant growth, physiology and disease. For example, they will inoculate greenhouse plants with specific microbes to see how the plants cope with this challenge under different oxygen levels.[/FONT]
[FONT=&quot]Other researchers involved in this project include technician Linping Wang, graduate student Johanna Valentine and undergraduate student Mark Mallany, Department of Environmental Biology.[/FONT]
[FONT=&quot]This research is being conducted at greenhouses in Guelph and Leamington , Ontario . It is sponsored by Seair Diffusion Systems Inc., Flowers Canada Ontario and the Fred Miller Rose Research Fund. [/FONT]

It all works. I've done it all. I like to keep them pretty full. It helps to keep the temps down and makes nutes and PH easier to control. Works for me.

How big are the net pots? I run 10" net pots and I keep my level 2" above the bottom of the net pot. Because of how big these net pots are it's best to keep the water level above the bottom. Smaller net pots are best kept under. My plants drink 2 gallons a day. It drank less when I kept the water level below the net pot. So yeah, if you use large net pots keep it above the bottom and below for the smaller net pots.

WSRidahs said:

How big are the net pots? I run 10" net pots and I keep my level 2" above the bottom of the net pot. Because of how big these net pots are it's best to keep the water level above the bottom. Smaller net pots are best kept under. My plants drink 2 gallons a day. It drank less when I kept the water level below the net pot. So yeah, if you use large net pots keep it above the bottom and below for the smaller net pots.

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I don't know if you are right or not but that is the best answer to this question that I have seen yet. What you say at least makes sense.