Growing plants in controlled atmosphere indoor, for science!

[pigsknow]

Hi all, first post here. I have an interesting project that I am trying to get started...

I am a scientist/researcher at a major university, and one of my projects could greatly benefit from growing plants in the lab for Carbon-13 and Nitrogen-15 isotope enrichment. Essentially, I want to grow plants (for starters, probably lettuce and/or beets) indoors, with a controlled atmosphere. I need a sealed chamber so that I can introduce 13C- carbon dioxide, and I will use 15N - ammonium nitrate as fertilizer

The general plan would be to start with germinating seeds, plant them appropriately in unfertilized soil in clear plastic trays, and place into a glove bag (sealed inflatable container, 37 in by 37 in by 25 in). The soil would be artificially fertilized using Nitrogen-15 ammonium nitrate. The glove bag would be sealed and inflated with atmospheric amounts of N2, O2, CO2 (13C CO2), etc. An appropriate lighting source would be placed above, likely outside of the glove bag.

questions:
1 - how much space is needed to grow lettuce / beets indoors? Ideally I need to do this inside a glove bag that is 37 x 37 x 25 inches
2 - what kind of lights do I need for indoor growths?
3 - how large do the seed spacings need to be for lettuce and/or beets?
4 - what kind of soil is optimal? Remember I need soil that is very nutrient-poor, so I can add nutrients of my choice that are 13C/15N isotopically enriched
5 - is there any reason that too much CO2 would be a bad thing? ie, atmospheric CO2 is about 0.04% by volume, could I increase to 1% for faster growth?
6 - are there any obvious reasons why this would not work?
7 - what containers work best for lettuce / beets?
8 - are there any oxygen and/or CO2 sensors I could use to help regulate the atmosphere?
9 - how much do I need to water the plants?

Please feel free to comment or question, or address any or all of my questions. Thank you in advance for any help!

 

[catjac1975]

The only response I can give is coir is a good substance for seed starting that has no nutrients at all. I get mine from worm's Way but many places sell it. I would think mold might be a problem in a sealed environment. I soak my seeds in hydrogen peroxide and water to deter mold. Or sometimes I add a few drops of chlorine bleach. (I grow saved daylily seeds that I have to chill in a moist container) How this might effect the science of it I do not know. The hydroponics guy on the forum probably knows a lot. Disney's Epcot Center has a grow lab exhibit and do a lot of alternative growing systems. Education is big for them. I 'm sure there must me info on a web site.

 

[Chickie'sMomaInNH]

you might want to check with Jackb about stuff like this. he does hydroponics in a somewhat sealed environment. even in that you still want to have airflow over the soil and around the plants. it will help the plants thrive better and keep the possibility of fungus and mold down. he has a link to his webpage if you ever come across one of his threads. he can also suggest types of veggies that are best grown in greenhouses under lights.

you were asking about how much space would be taken up with lettuce. it depends on the type you intend to grow. there are i think 4-5 different categories: Cos (Romaine types), Butterhead, Crisphead (like Iceberg), and loose leaf. to get a bigger bang for your buck (or experiment) i would suggest the loose leaf. they are a type of cut and come again and take less time and much less space to grow. the other 3 types can tend to take up a square foot of space.

depending on how quickly you want results from this i think i would go with something other than beets for a root crop, try radishes instead. most take between 23-30 days before they are good to harvest. beets can take longer to grow unless you are just growing them for the greens.

 

[897tgigvib]

You will visit a HYDROPONICS store.
A good hydroponics store, probably the owner, and not the manager, will be the one to talk to.

I know that you have a great many more variables and controls than you have mentioned. You will need microorganism counts and species because those will affect things a lot if they are not even in numbers and kinds.

I believe that there will be some hydroponics nutrients manufacturers that will be very interested in this.
You may well want to google for Dutch Master nutrients.

There are coco fiber products and some matrix products based on pumice and some on clay. Perlite might make another good control. Some situations can use exotic things as the matrix.

Your lights for those plants should be t5 flourescent. A good hydroponics shop will have several kinds with spectreal qualities. Probably wide spectrum for you.

Beets have several seeds per "seed", so don't forget to thin them. In the garden beets like 5 to 8 inches give or take on who says what. Lettuce can be as close as an inch for making a bed of cutting leaf, or over a foot apart for growing nice specimens.

There indeed are co2 sensors, don't know if there are o2 sensors. There are even co2 making machines for some certain greenhouses. i do not think those differentiate electron counts.

A possible reason this may fail...thinking, brb...ok, i'm back after thinking.

You will need some equipment for quality control. You're going to need a chemical analyzer, the kind that you put rarified gases into a tube and run electrity through it, basically making a temporary flourescent tube, to see and analyze its emission points to know for sure your ratios are right, both for the co2 and for the n2 that will make the ammonium nitrate. There may be different reactions with different atmospheric ratios of the n2 also.

If successful, you may find an advantage in creating organic, bio derived nutrients using a ratio you find best.

=======



Welcome to the forum!

Are you a student researcher? This does sound like a project among others for a masters. I think you'll be wanting to compare transpiration rates along with growth rates.

 

[digitS']

The greenhouses where I worked, each had CO2 generators.

Every house had a long, perforated plastic tube at its peak. Blowing into this tube was a natural gas furnace. It was nothing more than that. The natural gas was burned just for producing CO2 so, of course, it was not vented out of the greenhouses.

Set on timers, the things would run every night during the summer and continuously during the winter. The argument was that the plants generated plenty of O2 so, to keep things growing when the houses were closed up, it was important to burn gas. It apparently mattered little that those big glass houses leaked air like a sieve. Increasing the CO2 was the aim and I have no knowledge of the levels ever being measured once.

Off Topic: Workers weren't asked what they thought about this set up. But then, we were not asked about the use of pesticides that were "vaporized" overnight. "Vaporized" simply meant that they were burned in what were essentially electric fry pans until the air was dense with the pesticide. These, also, were on timers and our day began in a cloud but things cleared during daylight hours.

Workers were also not asked about pesticides added to the sumps so that they evaporated with water when the air conditioning was running. Of course, this was taking place during daylight hours since the air conditioning was only running during those hours. When Dieldrin was banned for use in greenhouses but continued to be used on tree farms & such, the owners found a supply from their friends growing ornamental grasses. Years after it was supposed to be gone, gone, gone from a closed environment - it was still being used, used, used. This kind of shows you that substances cannot really be banned as long as there is money to be made in their trade. It must be part and parcel to the spirit of entrepreneurialism.

Steve

 

[897tgigvib]

Digit, has the statute of limitations yet passed that the owners of the greenhouse you worked at were using the banned substances? I would have turned them in a long time ago. The last thing the economy needs are a bunch of white collar criminals.

 

[digitS']

Oh, I imagine so, Marshall.

I did get them to stop using the Dieldrin but I had to take a day off to talk to university horticulturalists to figure out what was going on. The company always seemed to be on some sort of financial "brink." That was the situation that was always portrayed. They made me feel like I was endangering the entire enterprise whereas, I was just reacting to learning something that their buddy in the grass business let drop.

And, speaking of the business . . . isn't it usually wise for the gardeners to turn to university horticulturalists for expertise . . ?

Steve

 

[897tgigvib]

I don't know pigsknow's situation Digit, but it looks here like the university is asking gardeners for advice in this situation.

Yes, of course normally we'd be looking at a uc davis site for some difficult horticulture problem, um, like for a dominant or recessive trait crossing tomatoes or something.

I can only guess, and I sure hope pigsknow comes back to let us know, but this seems like part of a masters degree project. Who knows, but this could even have some implications for radiocarbon dating, which I do know is in the process of being made more accurate. I hear tell that it is possible for accuracy to tell which month 15,273 years ago a fossil animal died nowadays.

 

[catjac1975]

Wow- I wonder how many people unknowingly got sick in that environment? The excuse businesses always use is the financial brink.

Oh, I imagine so, Marshall.

I did get them to stop using the Dieldrin but I had to take a day off to talk to university horticulturalists to figure out what was going on. The company always seemed to be on some sort of financial "brink." That was the situation that was always portrayed. They made me feel like I was endangering the entire enterprise whereas, I was just reacting to learning something that their buddy in the grass business let drop.

And, speaking of the business . . . isn't it usually wise for the gardeners to turn to university horticulturalists for expertise . . ?

Steve

 

[pigsknow]

Thank you all for your advice!

The reason why I am hoping to do this project is not to do anything complicated, like monotoring CO2 uptake in various plants, etc. I want it for a much simpler reason: if lettuce or beets are grown under a 13C - CO2 atmosphere, the lettuce itself would be 13C isotopically enriched (about 1% of all carbon is 12C, but only 13C is useful from the standpoint of NMR - Nuclear Magnetic Resonance). my research tries to study the molecular composition of various silks (spider, silkworm, caddisfly, ...), and if I can get the silk-maker to eat food that is 13C/15N isotopically enriched, I can do a lot more with NMR. Nothing illegal here...lol

I will try to visit a Hydroponics store to get advice.

Thank you!
-pigsknow