LOL! tiG, they ARE in standard measurements. Not my fault if the US is the last dinosaur... Sorry, couldn't help teasing a bit. But if you would like it in non-standard American measurements...
For reference 5 centimetres = 2"
A litre is a bit more than an American quart
250 millilitres = 1 cup (close enough, it's a smidgeon bigger)
38ºC is about 100ºF
15º is about 60ºF
I think that should pretty well carry you through the article.
FWIW, we may possibly be moving to the States at some point in the future and one of the things that psychs my kids out is the idea of coping with American measurements. Unlike my generation, who went through the whole conversion process and can operate in either system, metric or Imperial, they've gotten nothing but metric in school and look at me all blank if I slip and use pounds or miles or Fahrenheit. Then it's them demanding a translation. And to make it worse, an American quart is smaller than an Imperial one, which makes the gallon smaller and ...
Being Canadian involves being bilingual in more than one way.
LOL!!! Well, it is standard in the States, just not in the rest of the world. And there's a lot of world out there. ;o) If it makes you feel any better, a lot of Canadians never did switch over too well. Except perhaps for temperatures and distances, seeing as all the signs and speedometers dropped the miles years ago and weather reports are always in Celsius. But cooks have clung fiercely to cups and all our measuring cups have both systems on them. Most rulers still include inches down one side too, but my kids just ignore that side... Metric is so much easier, they just couldn't be bothered.
Anyway, have fun with the gelatin. Personally, I like the idea of not having to water tiny seedlings.
I'm not too sure "boil for 5 minutes to sterilize" and "press the seeds with your hand" are compatable operations. Sterility isn't going to be there in most non-treated seeds, anyway. I'd keep the lemon juice handy. :)
Cool article, nonetheless.
In the end, I would like to ask, as I live in Greece, which is not only metric but also does not have the gelatin available everywhere as it is not popular.
Is the principle or the detailed measurements that works ?? Could I do it, e.g. in wallpaper glue thick enough ?? It is only cellulose, as opposed to gelatin which is made of cow bones and has the risk of encephalopathy !
Why fertilizer and not peat moss added to the gelatin ?
I kept watching this thread for updates and just realized that Janet did not subscribe. Now we will never know how her experiments are working out. Is anyone else trying this? If so please let us know how it worked for you and if you had the mold problems.
Dimitri, I don't know the answer to your questions but if you want to try this I can pick up some gelitin at the grocery and send it to you.
This message was edited Wednesday, Nov 14th 3:49 AM
Hi Zanymuse, long time since I communicated with anyone at DG. I am building my house, and too much work leaves not enough energy to chat re. seeds etc.
Thank you, I don't want gelatin. What I do is quite effective : 40% clay soil, 60% peat moss, put the seed in a seeding pot (2" x 2") and repot when 2nd set of leaves is developing. The gel comes EXTREMELY handy, is when I want to sow directly to the ground a lot of minute seeds (like dandelion, e.g.) then I prepare wallpaper glue, throw in the seeds, mix well, and sow with a pastry funnel, or even by the spoonful !!
PS some photos from spring and summer will be for the winter nights - I hope soon
I started some seed in the gelatin and it did real well for about 5 days, then some mold started where the seed was. It caused the gelatin to desolve. There was a tiny pond around each seed.After I sprayed the surface with the bleach mixture it seemed to stop. Later the hollow places where the ponds were got bigger. This ment that more of the gelatin was dissolving. I sprayed again after pouring the watery liquid off. Every day after there was more of the gelitan dissolved until there was only about 1 in. left. I removed the seed and started another batch of gelatin, hopefully the seed will sprout soon.
That seems to be the big problem with this method. Please let us know how you do with the next batch. I am wondering if there is another medium that might work better like those pellets you add to keep soil moist longer. I haven't seen them but a friend said they are kind of like jello.
I have thought for a long time this world work. So yesterday, I decided to try it, not with regular gelatin but with water absorbing polymer crystals. I used a few unpeeled brug seeds. Just an experiment. I root a lot of other things in them too, then I don't have to worry about letting the soil get too dry, a fault of mine. I'll let you know what happens.
I too was thinking the crystals would work better. They shouldn't break down like the gelatin since they are inert matter. I wonder if the tea-tree oil would stop the mold in the seeds. I use it when starting seeds in soil-less mix and don't have a fungus problem. I have a few extra seeds and will try this and let everyone know. I had forgotten about this thread or could have begun sooner.
*the new diapers have water absorbing crystals inside if you can't find the Water-sorb brand*
Lowes or HD (can't rememner which) carry the Agrisoak brand. They are $11.95 a pound but cheaper than Diapers I imagine!! lol. They didn't seem to work as well as I had thought for seeds - they did work tho, just not really any faster! The brug seeds I put in the soil are the same size as the ones in the crystals. Just a couple of days ago I transplanted the ones from the crystals to pots and also the ones from the starting tray of soil. They are about 4" high with 2 healthy leaves.
Zany, I just used water. As far as mold, no, they did turn a little green, but I call this alge. I have reused the crystals many times, just put them in a jar with more water and stir them arund til the green gets loose in the water and rinse them off, you can also put them in a strainer and just rinse them off. If you don't want to bother with this, you can just spread them out, let them dry out a few days and mix them in your soil.
Azalea, would you please tell me how o do this...is it crystals or powder? do you just put enough for an inch or two in the bottom of something? do you leave it where you can see water or not? thanks arlene
Arlene, use the cryatals. Yes, just put a small amt, enough just like you said for an inch or 2 in a container. I don't think you need to see the water, as long as the cryatals are fully expanded. I just sprinkled a few seeds, unpeeled in between the crystals. When they get roots and the first leaves, transfer them to soil.
Some of the crystals will hang on the roots, the roots grow right into them, this is good.
Azalea thank you, was wanting to try this, i have a seed phobia. btw, i liked your crystals a lot. wanted to let you know at watersorb.com they will send a sample for two 34cent stamps, they have a lot of info, can also buy by 2 lbs, 5lbs, 10lbs etc a lot cheaper than from lowe's.
This isn't quite the same as starting seeds in gelatin... but a tip I came accross that suggests to use Jell-o when planting seeds. Sprinkle any flavored Jell-o (with sugar) over the seeds when planting and then top with a thin layer of soil. The gelatin will keep the seeds moist and the nitrogen in the jello is supposed to speed sprouting. The sugar will feed beneficial soil microbes. It also says that jello helps to fight off fungal diseases. I wonder how this works. I might have to try it.
Here is the recipe with all of the measurements changed from metric to US measures.
Jump-start seeds with gelatin
It’s almost de rigueur for Prairie gardeners to start seeds indoors during long winter months to wring a few extra weeks out of a notoriously short growing season. Sowing seeds in soilless mix is the usual route, but Willem Kuyt, a Carvel, Alberta, gardener and nursery owner, uses a less traditional medium. Kuyt says using gelatin, which is rich in phosphorus and calcium, improves germination rates and produces sturdy seedlings. It’s also less expensive and cleaner to work with than soilless mix, he says. Kuyt moved to Alberta from Holland two years ago, where gelatin is used in universities to start seedlings indoors. Here’s how it’s done. The following recipe yields enough gelatin to fill one 19.75- by 9.75 inch tray or four 5- by 9.75 inch trays. Alternatively, use short Mason jars. You don’t need to water the germinating seeds, so drainage holes aren’t necessary. Whatever containers you use, make sure they’re deep enough to allow for a 2-inch layer of gelatin, which will accommodate about 1,000 tiny seeds (like poppy) or 200 large seeds (like bean).
In a 5-quart saucepan, sprinkle 6 oz of unflavoured gelatin powder over 17 oz of cool water. (Gelatin packages generally come in .5 Oz envelopes, so for smaller batches, divide water and fertilizer amounts by 10.) Pour 18 oz of boiling water into the mixture and stir one to two minutes, until gelatin dissolves. Add 1 oz of water-soluble fertilizer such as 20-20-20; stir for another two minutes. Add 2 Qts of boiling water, stir lightly and pour into wide-mouth Mason jars. Boil the jars in a canner for five minutes to sterilize the growing medium. Let cool to below 100ºF, then pour the mixture into plastic trays that have been washed with a 10 per cent solution of bleach and water, and then rinsed, or small Mason jars that have been sterilized. Place clear plastic or glass coverings over the trays or jars and let sit overnight. The next morning, sprinkle seeds liberally over the surface of the set gelatin, and press gently with your hand until the seeds are just below the surface. Place containers under fluorescent lights that almost touch the coverings. This will keep seeds at a comfortable 60ºF while they germinate. If mould develops on the gelatin before the seeds germinate, spray with a 10 per cent solution of bleach and water; if seedlings have emerged, use a 10 per cent solution of lemon juice or vinegar and water. When seedlings reach 3 inches, remove the covering and raise the lights to 1 inch above the plants. In about three weeks, most seedlings will be 2.5 inches tall and ready to be transplanted into individual pots or cell-packs, and placed in cold frames for hardening off. Slip the seedlings out of the gelatin with your fingertips—any residual mix on the plants won’t harm the transplants.
Hi dpmichael. I used to jump start my vegetable seeds this way quite a few years ago using wallpaper paste. You need to use the type without fungicides etc!!!! Seem to remember using it roughly double strength to give a gel consistency. It not only starts seeds well, but makes them easier to space when sowing. Use an icing bag idea (eg poly bag with a cut out of the corner. Then you can squeeze gel and germinated seeds into pots/trays/open ground depending on how you want to grow them on.
Thank you philomel. I do not have a problem with starting seeds straight into the soil, as already now (Late January) it feels, smells and shows like Spring - i know there will still be cold winds in 2 - 4 weeks time, but it is ok without very experimntal methods - yet, i like to learn other methods. Your tip sounds fine; so far, I have only used glue to distribute small seeds even; this year I found an even better one: You know kebabs, I am sure. When preparing them, cooks have a large red pepper sprinkler made of cheap aluminium. I took the cap off of one of those, and with a drill bit opened some wholes big enough for my danelion seeds (it is a delicacy here) and sprinkle the seeds walking along the small ditch which I later cover with an inch of soil. How's that ??
Paulgrow, could you direct me to the European measures ??
I have absolutely no idea about quarts and gallons...while I admire the Dutch for their agricultural knowledge.
Got to tell y'all, I am very disappointed in the results I had with the crystals. I tried Hostas, cockscomb & zinnias about 3 weeks ago. The Zinnia & Cockscomb came up very well in just a few days, one was about 2 inches tall, then, suddenly they all just keeled over!! Most were too small to transplant so they just went to never, never land. The Hostas never did come up. Now I did have success with unpeeled brug seeds. Maybe it was because they have a larger stalk??? So maybe this method will still be ok for larger seeds. I am going to try some moon vine and Hyacinth beans, & maybe Castor beans.
Read in a garden magazine recently that an old French way of starting seeds was to make your own "peat pot" type seed starters by using the (peat/vermiculite/perlite) soiless mix, as a base, but instead of wetting it with regular water, wet it with gelatin water. Once the soiless mix is wetted, form the mix into little "peat pot" type balls, or seed starters. This also eliminates the need for slotted trays, as these are individual and do not need pots/containers.
The gelatin was reported to help hold the "peat pots" together, while also preventing them from drying out too quickly, and adding nutrients to the soiless mix.
Seems this would be kinder to the little sprouts, as you could transplant the whole thing right into the ground (as is...), without the disturbance of taking them out of the pure gelatin, and risking transplant shock, or tearing the tender roots.
No, I have not tried it yet. I was very much opposed to this idea, as I remembered from Biology 101 just what kind of nasties one could grow from the slightest contamination (such as a cough).
HOWEVER, there is a technique I wanted to try, where one does a seed embryo rescue, dissecting it out of the seed and growing it on a nutrient media, often agar. That would require some scientific equipment, and perhaps mixing up a media, things a bit beyond my scientific grasp. Then I remembered this gelatin idea, and thought that should work as well.
Otherwise, I think one can purchase Petri dishes or test tubes already full of agar/nutrient media to use. I am still concerned about contamination...
I did a test using coral vine seeds. I sowed some in regular soiless mix, and others in my adapted version, by using the gelatin water to wet my soiless mix, instead of just plain water.
It really worked well!
It held the soil together really nicely, and the gleatin seeds not only sprouted about a week sooner than the ones in regular soiless mix, but grew much more quickly than the others!
I'm impressed with this method!
Taylor, how large are your seedlings at this point? Have you noticed any sign of mold or damping off from the gelatin seedlings? Please keep us posted of your progress! It will be interesting to see your final results as the seedlings grow.
Yes, Scooterbug, there are nutrients in the gelatin, that is kinda the point...
They are not leggy at all. They'd only be leggy if they weren't getting enough light, not because they got too much fertilizer. They'd burn(turn brown) if they were getting too much nitrogen. Gelatin is a rather mild dose-perfect for seedlings which normally are suggested to have 1/4 the normal strenght of regular fertilizer.
They grew so well, they have been transplanted into pots with soil already. They are well on their way.
I'll have to start some other things this way.
I had two damp off(out of about 20) that were tested in the regular soil, ---but NONE, out of the batch in gelatin...
What kind of gelatine did you use? Jello? Knox Sparkling Gelatine?
Also, did your "gelatine peat pots" actually hold together on their own, as separate little things? If so, I guess they would be suitable for direct planting in the ground if they hold together that long. How do you water them without causing them to disintegrate?
I used the knox unflavored gelatin. I really don't remember how I mixed it, and there certainly wasn't a section between jello and pie instructions, discussing mudballs! lol...). I think I just made one packet per the instructions for jello. (It starts out watery, but thickens as you let it set). I then used a plastic sink tub and slowly hand mixed in enough soil and gelatin until it was perfectly moist, but not wet, or dry. I then sqeezed them into little balls.
You have to mix it in with the soiless mix pretty quickly, or it will set, if you leave it(obviously...).
They held together pretty well on their own, and firmed more as time went by, but cannot tell you exactly how well, as I put them in the slotted parts of a platic egg carton, which sort-of cradled them. That was my "tray" and kept them neat and from falling over. I only had them in this about a week and a half, before they were sprouted and already outgrowing their little "mudballs". I had them near a fan to help with circulation, but it also caused the tops to dry out a little, so I did have to water once, but just a little on top.
You guys need to try it! Let me know how YOU do!
The gelatin is cheap, and you could experiment with seeds that you have plenty of...no risk
Everyone has their own way of staarting seeds and being you are all talking about gelatin, this is the way that I start my seeds.
After filling the flats with seed-starting mix I sow the seeds and then lightly sprinkle gelatin powder over them using an old salt shaker. Then press down the gelatin and seeds in and cover everything with a thin layer of starting mix. Then mist the top and cover it with wet paper towels.
Place your flats in warm area, around 65-75 deg. Keep misting the paper towels occasionally to keep them moist and be sure to check the flats for sprouting.
Once you see new growth coming, remove the paper towels. Once the seedlings start taking off, feed the plants liquid fertilizer with a teaspoon of gelatin powder mixed into 1 gal of water.
i get unflavored gelatin in 10 lb boxes much cheaped then the Knox brand if anyone wants i will add it to my scif store i just brought home abiut a pound and am going to try this for starting my tomatoes and basil this week. so if i understand all this right i can make the gelatin as i would for eating then mix it into my spaghnum moss to make it wet then use the mix to fill my seed trays.
This method is similar to Tissue Culture, thats what I do to most of my plants. Getting the seed clean is pretty easy. Shake the seeds in 70% Alcohol for about 30 seconds, rinse with sterile water, then use a 15% bleach solution for 15 mintues, triple rinse in sterile water and decant... Seeds should be pretty sterile... I used this on some hosta seeds and it worked very well... My jars that I am starting my plants in are sterile from a pressure cooker... and I use a clean box and a laminar flow hood too to prevent any mold spores from getting into the container... if you need any help on this please email me!
Oh my, you're right. It doesn't work. I remember reading that link and it was very good. Maybe you could contact JanetR by D-mail and ask if she possibly saved it to her hard drive? I'd be interested in saving it myself right about now.
Your local Chinese grocery will have gelatin and agar. Ethnic stores are usually cheaper then the seven American grocers. I have also bought kosher gelatin at a Mexican grocer both bulk and packaged.
Imagine that Botany an 'librium on the same forum!
I see that JanetR first registered in 2001 but she is no longer active. People come and people go and sooner or later she will check in.
Just in case my url goes down I am going to cut and paste what was at the URL I posted a link to.
Quoting:All About Agar
With its distinctive smell, one can easily distinguish agar from the other materials commonly found in a laboratory. Chemically, agar is a polymer made up of subunits of the sugar galactose, and is a component of the cell walls of several species of red algae that are usually harvested in eastern Asia and California. Dissolved in boiling water and cooled, laboratory agar looks gelatinous. Although agar's chief use is as a culture medium for various microorganisms, particularly for bacteria, its other less well-known uses include serving as a thickening for soups and sauces, in jellies and ice cream, in cosmetics, for clarifying beverages, and for sizing fabrics.(1)
One might ask why agar, as opposed to regular gelatin (like that found in Jello), is used for culturing bacteria. The answer is agar, unlike gelatin, won't be degraded (eaten) by bacteria. Also, agar is firmer and stronger than gelatin. It's still possible, however, to use gelatin as a culture medium for bacteria if agar is unavailable.(2)
The Difco & BBL Manual gives more details about agar and its usage:(3)
Agar is a phycocolloid extracted from a group of red-purple marine algae (Class Rhodophyceae) including Gelidium, Pterocladia and Gracilaria. Gelidium is the preferred source for agars. Impurities, debris, minerals and pigment are reduced to specified levels during manufacture.
Agar is a gel at room temperature, remaining firm at temperature as high as 65°C. Agar melts at approximately 85°C, a different temperature from that at which it solidifies, 32-40°C. This property is known as hysteresis. Agar is generally resistant to shear forces; however, different agars may have different gel strengths or degrees of stiffness.
Agar is typically used in a final concentration of 1-2% for solidifying culture media. Smaller quantities (0.05-0.5%) are used in media for motility studies (0.5% w/v) and for growth of anaerobes (0.1%) and microaerophiles.
Specifications for bacteriological grade agar include good clarity, controlled gelation temperature, controlled melting temperature, good diffusion characteristics, absence of toxic bacterial inhibitors and relative absence of metabolically useful minerals and compounds.
For students growing bacteria at home without the supervision of a teacher (for example, investigating bacteria growth at various places around the house), it's important to use an agar formulation that does not preferentially grow one kind of bacteria over another. The worst case would be one that preferentially grew pathogenic bacteria. Therefore, we recommend a plain nutrient agar, of which LB agar is a subtype.
There are many different suppliers for LB agar. Because some suppliers will often only sell to students directly, you may have to have your teacher order for you. If you are doing a project that involves inoculation and plate streaking, we highly recommend conducting the experiment at a school lab under teacher supervision.
Some suggested suppliers are:
Supplier Catalog Number Contact Info Cost Number of plates
Science Kit & Boreal Laboratories WW6564600(4) www.sciencekit.com
800-828-7777 $9.57 for 6 pre-poured plates of nutrient agar 6
Carolina Biological Supplies 82-1045 www.carolina.com
800-334-5551 $23.25 per kit (enough for 20 plates) 20
Bio-Rad Laboratories 166-0600EDU www.bio-rad.com
800-424-6723 $8.00 for 6.9g of LB Nutrient Agar Powder 40
Sigma L7025 www.sigma-aldrich.com
800-325-5832 $63.60 for 100 tablets (1.68g per tablet) 500
Common Types of Agar
Type of Agar Brief Description Suitable for Student Use?
Blood Agar Contains blood cells from an animal (e.g. a sheep); most bacteria will grow on this medium. No, due to potential for contamination from human contact.
Chocolate Agar Comprised of sheep blood that provides the X and V factors necessary for Haemophilus growth, this is a nutrient medium which is used in culturing fastidious organisms such as Haemophilus species and Neisseria. Chocolate agar, however, does not reveal hemolysis data, so species differentiation among the members of Haemophilus must be performed in another manner. No, due to potential for contamination from human contact.
LB (Luria Bertani) Agar A subtype of nutrient agar, this is the general medium for microbiology studies and may be used for routine cultivation of not particularly fastidious microorganisms. Also, does not preferentially grow one kind of bacteria over another. Yes.
MacConkey Agar This is an agar upon which only Gram-negative bacteria can grow. What is more is that E.coli will grow into red colonies, as there is a pH indicator present. It should be mentioned that MacConkey agar powder comes in two versions: one with the sugar lactose in it, and one without any added sugars. Since E.coli ferments sugars to acids (thus the red color), one can add one of the many different kinds of sugars to this sugar-free MacConkey agar and see if red colonies develop. If you get red colonies, you know the E.coli strain you are using can use that sugar. No, due to selectivity.
Miller's LB Agar This common variation of LB agar appears to have the same components as LB, just in different proportions. Yes, but sticking with the generic formula is recommended.
Neomycin Agar Contains the antibiotic neomycin, which found in many medications such as creams, ointments and eyedrops. Neomycin was discovered in 1949 by the microbiologist Selman Waksman, and it is produced naturally by the bacterium Streptomyces fradiae. Moreover, Neomycin has a broad spectrum of effects, killing both gram-positive and gram negative bacteria. It is relatively toxic to humans, and some people have allergic reactions to it. Often, Neomycin agar is used for culturing organisms anaerobically. Neomycin stops the growth of gram-negative bacilli and staphylcocci, allowing Streptococcus species to grow more abundantly. No, due to safety concerns.
Non-nutrient Agar Usually not suitable for growing bacteria. However, may be used for growing other microorganisms. No.
Nutrient Agar Will grow the largest number of different types of microbes - fungi and bacteria. Yet, not all bacteria can grow on these. Some find it too rich, and others find it deficient. The nutrient in this is beef broth, and some extracts from yeast. Yes, because it does not selectively grow pathogenic bacteria.
Sabouraud Agar Used for fungi and has a low pH that will kill most bacteria. It contains gentamicin, which is a aminoglycoside antibiotic. Gentamicin can also treat many different types of bacterial infections, particularly Gram-negative infection. No, due to safety concerns.
Thayer-Martin Agar Chocolate agar designed to isolate Neisseria gonorrhoeae, also known as "gonococcus," which is a species of Gram-negative bacterium responsible for the disease gonorrhoea. No, due to potential for contamination from human contact.
Tryptic Soy Agar A basic medium used for culturing many kinds of microorganisms. Tryptic soy agar is mainly used as an initial growth medium for the purposes of: observing colony morphology, developing a pure culture, achieving sufficient growth for further biochemical testing, and culture storage. No, due to selectivity.
XLD Agar Xylose lysine deoxycholate agar. It is used for the culture of stool samples, and contains two indicators. It is formulated to inhibit Gram-positive bacteria, while the growth of Gram-negative bacilli is encouraged. The colonies of lactose fermenters appear yellow. No, due to selectivity.
Preparing Bottled Agar and Plates(5)
Pre-experiment: Keep sterile Petri dishes closed until ready to pour agar into them. Air-borne contaminants can easily invade an open Petri dish.
Although pre-poured agar plates are available, one can make agar plates from tablet, powdered, or bottled agar by following a few simple instructions. Agar kits usually come with detailed instructions on how to prepare plates, and below are sample procedures for reference. When in doubt, be sure to clearly read the instructions and ask for help if needed (either consult a teacher or call the technical help line of the agar kit supplier).
Preparing Tablet or Powdered Agar:
The formulation for LB (Luria Bertani) agar is: 9.1 g/L tryptone, 4.6 g/L yeast extract, 4.6 g/L NaCl, and 13.7 g/L agar. If using tablets, dissolve 10 tablets per 500 ml of water. For agar powders, dissolve by microwaving, 6.9 g of agar in 500 ml of water. 500 ml of agar will pour ~ 25 large Petri dishes (100 mm diameter) or 50 small Petri dishes (60 mm diameter).
Preparing Bottled Agar:
Loosen the bottle cap, but do not remove the cap while heating.
Warm the agar bottle in a hot water bath or in the microwave until it becomes liquid.
After opening the cap, pass the neck of the agar bottle through a flame to sterilize it. Do not lose the cap!
While pouring the agar, open the Petri dish lid as little as possible, hold it at an angle, and make sure the lid is kept directly over the Petri dish.
Pour enough melted agar into each sterile plastic Petri dish to cover 1/8" of the bottom. Cover the lid of the Petri dish immediately.
Place agar plates on a counter top to cool and set. Agar medium will set like stiff gelatin at room temperature.
Pass the neck of the agar bottle through flame again before applying the cap.
Preparing Pre-Poured Plates: If plates have been refrigerated, set them out and allow them to warm to room temperature.
Storage: Stack agar plates upside down in the refrigerator. Do Not Freeze! The purpose of placing the plates upside down is to prevent condensation from dripping down onto the agar surface which could then facilitate movement of organisms between colonies.
When stirring the broth solution, one should take special note in beginning the stir scale at a low setting and adding more speed from there.
When heating the broth, make sure to cover the flask in such a manner that will not lend itself to boiling over, but to avoid spillage.
When pouring the broth, make sure to fill the Petri dish without burning oneself. In addition it is important in this process to make sure that the Petri dish is covered immediately to allow the substance to cool proportionately.
Once the Petri dishes have been exposed or inoculated, students should not re-open them.
Place each Petri dish inside a zip lock bag to prevent drying out and to control odors. Turn the plates upside down and put them in a warm place. For many microorganisms, the ideal temperature for incubation is 32°C or 90°F. Bacterial growth should start to become visible in 2-3 days.
For those growing bacteria at home (for example, investigating bacteria growth at various places around the house), you may use a homemade "light bulb incubator" in place of a laboratory incubator. This page describes how to construct a "light bulb incubator:" http://www.umsl.edu/~microbes/pdf/Incubator.pdf
Once the Petri dishes have been taped shut, they should not be opened again. All microorganisms grown during the experiment should be killed before discarding. The best way to dispose of bacterial cultures is to pressure sterilize them in a heat stable biohazard bag. If autoclaves or pressure cookers are not available or large enough to make this convenient, an alternative is to bleach the plates. Saturate the plates with a 20% or "1 in 5" household bleach solution (in other words, 1 part bleach and 4 parts water). Let them sit and soak overnight in the bleach solution before disposing of them. Please note that the bleach solution is corrosive and needs to be thoroughly removed afterwards. In addition, the plates can be incinerated if access to an incinerator is available.
(6) Mott, et al. "Artificial Environments for Growing Bacteria." WW Bio Institute. http://www.woodrow.org, (www.woodrow.org/teachers/esi/2002/Biology/Projects/lab_skills/ls5/), accessed January 14, 2005.
I tried the micropropagation method... using gelatin... with no success... (this was a few years ago). I got a lot of mold, even though everything was sterilized. Probably wasn't the same procedure though.
I have experimented with media. They break down as the glucose is consumed. Agar is usually used in Tissue Culture. It is mostly the sugar galactose. [Lactose (milk sugar) is glucose+galactose]. The alternates are also principally formed from galactose. Agar is available at your local Chinese grocery. Gelatin would work for quick germinating seed, but does not hold up long term. In TC Agar is combined with sugar as a nutrient. The sugar is consumed and the gel remains firm.