Hydroponic Tomatoes

[Elagrow]

Originally Posted by Crandrew

I'll be interested to see how it keeps developing the fruit. This is where the Light and nutes play a big part. Without proper lumens the fruit will grow slowly and potentially not develop properly. I'm interested to see how that 50hps works.

Well the 50w hps is in a small area... I am also interested in seeing how it develops to.

[Elagrow]

I have been taking pictures every few day's since the first set of tomatoes started growing, since then there has been about 8 more tomatoes sprouting up on my plant...

I will post a few pictures later for you all to look at!!!

[Elagrow]

I plucked a tomato from my Hydro Bitonto today and tasted it, it was probably the furthest thing from flavorless. Was a good burst of sour and salty, and was a medium meet tomato.

Heres a couple picks I took along the way.

[Cole_Robbie]

Awesome! Believe me, I am really happy to hear that. I hope to get my first hydro tomatoes up and running this spring.

[Elagrow]

Originally Posted by Cole_Robbie

Awesome! Believe me, I am really happy to hear that. I hope to get my first hydro tomatoes up and running this spring.

I am happy to... I hope to up the scale to a full room in the next month or two. I have a perfect place in my shop to setup a nice size hydro room.

[Sequim]

I converted my entire workshop to a hydro room in 2008 just for growing winter tomatoes and lettuce. This 2012/2013 season is my fourth, and I think I've finally gotten things close to right.

Let me know if you'd like to see any pictures and/or comments of what I've learned over 4 years. It might help you avoid learning something the hard way.


Pete

[Cole_Robbie]

Sequim, have you ever tried to analyze the market value of the food you produce versus your electric bill? That is what interests me the most, being able to operate hydroponics profitably. I have never seen a setup use 100% artificial light and still be profitable, but I would like to think it can be done.

[Sequim]

I have the lab instrumented so I know exactly the energy consumption, but I've worked hard at not analyzing it. It is just a hobby for me, and its not important to put a price on the high quality food we get from the endeavor.

Our electric rates here are reasonable though; about 6.5 cents per kilowatt hour. The winter lab requires no supplemental heat because the lights deliver more than is needed. I dispose of the extra with small window openings and the less-than-perfect performance of the heat recovery ventilator.

I hope to replace the T5HO lighting with LED lighting next winter, which should reduce the waste heat. Hopefully the reduction won't lead to a deficit.

I am told that lettuce under lights can be profitable in some circumstances. It is grown this way widely in Japan under LED lighting, for instance. Hasn't been this way for long but is quickly getting more reasonable. The big breakthrough has been 660 nanometer (deep red) wavelength LED's, now becoming plentiful.



Pete

[Elagrow]

I would love to see pictures and notes on what you have learned...

Also, I have researched LED's although the start up price is super high, they last for a very long time, and use next to no energy, and will grow better then any other lighting as long as you have a good spectrum ratio, which in turn I have also heard is a huge problem with LED's getting the correct mix of colors is hard to get the most out of them.

I have a 1800 sq ft warehouse with a perfect area to setup a small room probably about 6ftx10-12ft and around 15ft high I want to grow tomatoes obviously in there, but also thinking about doing herbs, peppers, and maybe strawberries, and maybe some vine fruits. I would like to keep the number of different solution containers down to as few as I can, should I use a different container for each different species? or can they all share the same solution? I want to setup a system that auto fills the containers when they run low... I am sure I can figure that out easy enough, but just not sure how to split up the containers.

[dice]

From another thread, you need low pH around 5.5 for the strawberries.
The other plants will probably need pH a point higher than that. So at
least those probably need a separate solution.

[Cole_Robbie]

I think HPS and metal halide lighting still deliver more lumens per watt of power consumed than LED lighting. LEDs only seem more efficient because they are so tiny. LEDs can have a spectrum advantage, but I still don't think they are cost-efficient overall.

[Crandrew]

LED's are literally on the cusp of the breakthrough. Currently even the cheap ones will veg any plant fine!
One issue you run into is finding the correct spectrum for flower and fruit. Another HUGE issue is that 80% of the units are made very very poorly leading to failures. I would run HPS without a doubt before I ran LED, until it gets worked out and there are proven consistent proven results. So far the results do not share a close enough correlation.

tl;dr - LED Cost is too high, results arent consistent.

[Elagrow]

HPS and MH lighting is good.

any suggestion with CFL's? they are cheaper, and run alot cheaper then hps? also they are alot cooler.

[Sequim]

Elagrow:
I'll work up some notes and pictures for you. I'm a bit slow these days so it might take a few days.

You should not combine unlike plants in a single solution. Besides pH preferences nitrogen preferences are perhaps even more specific. Strawberries and tomatoes are quite far apart in this regard.

I've grown hydroponic strawberries only two summer seasons outside, and never under lights. This spring I'll try starting them early in the greenhouse (didn't have a greenhouse the previous seasons) and will use a grower that is more space-efficient. I'm not sure its appropriate to present strawberry experiences on this forum so if you want to know more I can PM you.

I grew hydroponic peppers in the greenhouse last summer and decided to not do so again. They take so long to reach harvest, and I'd rather eat more tomatoes and just buy a pepper now and then at Costco. Lovely plants to look at though. I'll try to remember a few pictures when I prepare the notes for you.

Regarding automatic solution top-off; I suppose this would be convenient but I've always done this manually. I consider each solution top-off to be an opportunity to adjust pH and EC. Be aware though that I retired in 1995 and have seven Saturdays a week to pursue my hobbies.

Anyhow, an elevated auxiliary solution reservoir reservoir and a float valve in the main reservoir should be the answer to your top-off wish.

Pete

[Sequim]

I've been dabbling with LED plant lighting for a couple of years. So far I've not had great success, but by now I've done enough things wrong that I'm hopeful for good results on my next round. This time I will use the newly-available 660 nanometer LED's which I think will bring a big improvement. Please let me further explain why I believe that LED plant lighting promises a great future.

The best modern white LED's deliver 150 lumens per watt, which is considerably better than the best metal halides at 116 lumens per watt. High pressure sodium can also reach 150 lm/W, and if you can tolerate the color you can get 200 lm/W from low pressure sodium. T5 fluorescent can deliver slightly over 100 lm/W if driven by a high quality ballast.

But for plant lighting, white LEDs are not the best choice and "lumens per Watt" is not meaningful. Lumen is a metric entirely based on the spectral response of human eyes. It expresses how bright light appears to us. Plants see light much differently.

Studies made many year ago on pigments extracted from plant tissue revealed a series of spectral wavelength absorption peaks. The most prominent of these are chlorophyll A peaks at 430 and 662 nanometers, and cholorophyll B peaks at 453 and 642 nanometers. The 453 and 662 nanometer peaks are the greatest and it is now believed that most or possibly all plants will thrive under light with only these two wavelengths. Keep in mind that these tests were made in a laboratory on isolated pigments. We may someday discover that living plant tissue has other preferences.

The 453 and 662 nanometer peaks are at the fringes of human eye sensitivity. They just don't appear very bright to us, so their lumens per watt metric is very low. Here are two examples to help clarify this.

That best modern white LED I mentioned above, the one that can deliver 150 lumens per watt, is actually a 455 nanometer royal blue LED that has been coated with a phosphor to convert the blue light to white. This conversion is less than 100 % efficient so some light energy is lost in the process. Still the white light appears so bright to humans that they quantify it as 150 lumens per watt of power delivered to the LED. That same royal blue LED driven at the same wattage, but without the phosphor conversion coating, might measure out around 20 lumens per watt.

As I mentioned above, plants have an entirely different perspective. Light near their 453 nanometer peak is fully absorbed. You could say they see it as very bright because they suck it all in and make maximum use of it.

Now consider a different color; lets choose 555 nanometer green light which happens to be the very peak of human spectral response. If an LED could be made that would deliver 100% of its electrical input energy into 555 nanometer green light it would measure 683 lumens per watt. But a nearby plant would ignore this green light and in fact would reflect most of it away. And this is why humans perceive plant tissue to be green.

The point of the above verbage is to suggest that you should not be misled by a lumens per watt specification when considering plant lighting. The only meaningful metric would be "watts radiated per watt input", and this is only meaningful if the wavelength corresponds to one of the pigment absorption peaks. This reveals the awesome potential that LED's offer for plant lighting. They can be manufactured to efficiently deliver their radiated energy to the plant without wasting a lot of it in spectrum regions that the plant ignores.

I should mention that plant tissue contains photosensitive pigments other than chlorophyll. Of these phycoerythryn, phycocyanin, and beta carotene have quite prominent absorption peaks at about 560 yellow, 620 orange, and 450 blue nanometers respectively, so light near these wavelengths is not entirely wasted on plants. It is believed that these pigments do not process light directly, rather they absorb and re-radiate the light at 642 and 662 nanometer wavelengths to be absorbed and processed by the chlorophyll pigments. Of course this conversion process is rather inefficient, but it is the plant mechanism to make the best of whatever spectrum happens by.

I build my own LED luminaires. The ready-made models are optimized for mass production and shipping in small boxes, but their forms are not optimal for plants grown in rows. Mine are built in lengths equal to a T5 tube (slightly less than 4 feet) and can be cascaded as needed to cover a full row length. I also make them very thin, only 3/4 inch across, so I can use them for supplemental light in the greenhouse without casting a big shadow over the plants when natural light is plentiful. Finally, I form them around lengths of 1/2 inch copper pipe and water-cool them, so they can operate at much higher power levels than the ready-made air-cooled LED luminaires.

One more thing I must mention: Blue light causes cumulative irreversible degradation of human eyesight. Normal ambient light does not have enough blue content to deplete your vision reserves before the end of your life. But if you work with high power blue LED's on your plants you must use blue-blocking eye protection. If you don't you risk vision wearout before you check out of this world.


Pete