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Growing Bacteria Kit

Quick Overview

Our most popular all-inclusive Science Fair Experiment using easy-to-make nutrient agar.

Regular Price: $16.99

Special Price $11.95

Availability: In stock


You can smell a good science project a block away... especially when it's SICK Science™.

Creating an all-inclusive science fair kit can be difficult. The project has to be simple enough for young scientists to grasp, but the experiment also needs the ability to be taken further. That's what we've accomplished with the Bacteria Growing Kit. It's now wonder this kit is hugely popular with science savvy parents everywhere!

The Bacteria Growing Kit begins with the easy-to-make nutrient agar. This is the same nutrient agar used by microbiologists to grow really funky stuff in the lab. From there, everything you need is right in the kit: cotton swabs, petri dishes, and a microwave-safe plastic beaker. All that's left to do is design your experiment. Don't worry, we'll help you out there, too.

What's Included?

Bacteria Growing Kit
  • 6 large, 10 cm (3.5") diameter Petri dishes
  • 6 cotton swabs
  • 5 grams of Nutrient Agar
  • 600 mL plastic beaker
  • Activity guide

What Does It Teach?

We've designed a kit and guide to help young scientists develop an understanding of the scientific method while learning some awesome (and disgusting) science. The hands-on method, an great guide, and some gross science is all your child needs to get a kick out of science fair. Make sure you check out the "Additional" tab on this page to make sure you and your scientist grow bacteria safely and get the most out of the project you can.

Additional Information

Product FAQ

Science Fair Connection:

Just growing bacteria in a Petri dish is not a science fair experiment. Yes, it is gross and cool and fascinating, but it doesn't meet the requirements of a science fair project. If you want to do a science fair project about germs, you have to add a variable, or something that changes in the experiment.

With the Bacteria Growing Kit, adding an anti-bacterial hand sanitizer is a variable. Make one dish of germs and one dish of germs with a drop of the anti-bacterial sanitizer or, better yet, make three dishes--one as the control (just germs), one with an anti-bacterial sanitizer, and a third dish with another brand of anti-bacterial sanitizer. Then you can see which anti-bacterial sanitizer is more effective in killing germs. Just make sure that all three Petri dishes have germs from the same place in your home or classroom so that you know they are all exposed to the same bacteria. They also need to be grown in the same warm, dark place for the same amount of time so that the conditions are standardized as much as possible.

Growing bacteria is such a popular activity that we've written it up as a sample science fair project (see the link below). The sample project describes the swabbing technique to collect the germs and gives you lots of helpful hints about growing bacteria. It makes suggestions about variables and gives you some ideas to make the project your own. What it doesn't give you is the data. What fun would that be? Don't you want to do the experiment for yourself and see what discoveries you make?

Other ways to make the Bacteria Growing Kit into a science fair project:
Examples of Independent Variables: (choose only ONE independent variable to test)

  • Door Knobs
    • Start up question - Which door knob has the most bacteria?
    • Variations to the independent variable: bathroom door knob, your bedroom door knob, your front door knob

  • Mouths 
    • Start up question - Which mouth is the cleanest?
    • Variations to the independent variable: your mouth, your mom’s mouth, your teacher’s mouth, your dog’s mouth

  • Dental Care
    • Start up question - How clean does my mouth really get?
    • Variations to the independent variable: no brushing, brushing, brushing and mouth wash OR test different toothpastes - before brushing/after brushing with Colgate, before brushing/brushing with Crest, before brushing/brushing with Arm & Hammer, etc.


  • Is it dangerous? 
    You are growing bacteria and bacteria is not something that you really want around.  Always keep your lids and safety seals on your petri dishes.  You don’t want the spores to get everywhere and grow places where you don’t want them.  Also, throw the safety sealed petri dishes away in a zipper-lock bag. You don’t want to keep it because you are creating an environment for bacteria to grow and you don’t want growth to get out of hand.

  • How long does it take to grow?   
    Our little scientists were seeing results in about 24 hours with great growth after a week.  Your results will be dependent on the environment.

  • Is there a test for the type of bacteria?
    No.  The lesson here is to not really be able to identify which type you are growing but instead to record the growth.

  • Is your agar made from seaweed?
    Yes and no. By definition agar is a seaweed derivitive. However, our nutrient agar also contains soy nutrients to help facilitate bacteria growth.


Warning - Choking Hazard

Product Tags

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  1. Swabbed everything.. review by Cj on 4/27/2014

    My son swabbed everything he could think of, classmates volunteered belly buttons,hands etc, kids with sore throats, etc.. then they went swabbed cell phones and keyboards all of these examples yielded the wildest results!! This made my children and even my sons class mates aware of how important good hygiene is! Plenty of agar for dishes, it doesn't take much, to fill it to the half way point. Agar sets up fast! Directions are clear, and easy to follow. Thanks so much!

  2. Fun, but be careful! review by Lisa on 1/28/2014

    I decided to swab my tongue. Interesting stuff grew! A few days later, found out I had "walking pneumonia". We had to carefully dispose of that dish!

  3. Amazing Product! review by Leif O. on 3/31/2013

    I ordered a Bacteria Growing Kit for my fifth grade science fair project. The materials were great, shipping prompt and easy, and the directions were detailed and straightforward, making it easy to follow. Thanks!

  4. Awesome science fair item! review by Frederica on 3/16/2013

    My son used this for third grade science fair. He swabbed all of our pets to see who had the most bacteria in their mouths. The lizard won! No surprise there. Really excited to watch it grow and examine the results.

  5. Do Not Double Dip ! review by Althea on 2/4/2013

    I bought this kit for my 5th grade science fair project. It was very easy to use and was quite interesting. I didn't double dip before I did this experiment. Now that I have seen all the bacteria that it leaves behind, I encourage my friends not to double dip either.

  6. Bacteria Growing Kit review by HRK on 1/7/2013

    Your products are great. My only complaint is the shipping. Your shipping rates too high and too slow. With other companies I pay less than half of what you charge and receive my purchase in 3 days.

    HRK -
    Thank you for taking the time to review and for your feedback regarding the shipping rates. I would like to assure you that we charge the exact rates of shipping. We keep our products at as-low-as-possible prices to help counteract that. Again, thanks for the feedback. We hope that helps explain a little bit.
     - Steve Spangler Science Web Team

  7. Works Great and Very Quick!!! review by Ethel Cooney on 11/18/2012

    This was a fantastic experiment for my daughter's science project. Instructions were very clear and easy to follow and the results were unbelievely quick! We were growing bacteria in two days. My daughter and I had so much fun and learned so much. Thank you Steve Spangler!!!!!

  8. Science Project_2011 review by Devers on 10/7/2012

    We ordered the petri dishes for using in a science fair project. My daughter had a great time using the dishes and bringing the project together. Her friends had a great time watching the germs grow.

  9. Superb customer service! review by RK on 8/27/2012

    We have not used this product yet, but I did email customer service to verify if I had indeed purchased the correct product for my daughter's planned science project. My question was answered very quickly! Thank you.

  10. Great Project review by Marcia on 7/24/2012

    My 7 Year old son and I had a great time testing the doorknobs at my office and used it as a great reminder to wash our hands before we eat or touch food. Happy Experimenting!!!!

  11. Love it! review by Linda Klasse on 7/2/2012

    This is our second time to order your bacteria growing petri dish kit. We use them for science fair projects and they work
    great!! Thank you

  12. Who's mouth is cleaner- a Dog or Humans? review by Sarah on 6/20/2012

    I purchased this kit for my science project, Who's mouth is cleaner- a dog or humans? It was so fun. Everything you need is included in the kit and it's very affordable. I will definately be coming to this site again for my next science project.

  13. Bacteria growing kit review by Colleen Morris on 5/24/2012

    We are using this kit for a Science Fair project for my 4th grader. He and I think that it's really cool. We made and poured the Agar last night and can't wait until we see some growth. Very pleased with this kit and your company. About 10 minutes ago, I emailed a question and got an immediate response-you can't beat that kind of customer service! I plan to order some other experiments etc. and have Science Night once a week during the summer. Thanks,
    Colleen Morris

  14. Which grows more bacteria- a high schooler's mouth or the toilet? review by Kathy Patterson on 4/24/2012

    If this question has you yearning for an answer, you'll want to be sure and buy the Bacteria Growing Kit and find out for yourself. Our elementary students chose this question for their Science Fair project. Since there are enough materials to take 6 different samples, we also took samples from the water cooler, door knob, computer mouse, and stair railing. We grew bacteria in a variety of shapes and colors. My only caution is this ended up being a stinky project. We took pictures instead of displaying the actual Petri dishes. If your students love seeing gross things, however, this kit will certainly be a hit!

  15. Awesome! Buy now! review by James Bonilla on 3/3/2012

    I've bought this kit last year for my science fair project and it was pretty interesting. I did my project on what is the dirtiest objects and some everyday objects. (steering wheel, doorknob of the front house ...etc.... I loved the results and It has really fun! I would totally recommend it!

  16. Fabulous product review by Marci Steed on 2/1/2012

    We had a ball with this project! It was easy and informative as well as fun. The only thing lacking was finding out what each bacteria was afterwards. How could we do that?

    I would recomend this to parents, teachers, grandparents, anyone at all!!

  17. Great for Third Grade Science Project!!!! review by Kris on 12/30/2011

    Our daughter wanted to find out if her mouth, or her dog's mouth was cleaner before we even saw the question posed here. We found the "Bacteria Growing Kit" on line while trying to figure out where to get Petri dishes and Agar. Everything we nneded in one stop! What a success! So easy, and a true scientific process. Our dog is "Eausea" (pronounced OC). See pics here for results after 8 days. The final board looks beautiful with required Hypothesis, Procedure, and photos as well as her drawings(observations) of the "speckles" over time. Highly recommended.

  18. Bacteria Growth review by Stacey from Arkansas on 11/22/2011

    Very easy to use and students were fascinated by the results. Love this product!

  19. BACTERIAGROWING KIT review by MELINA GROOB on 10/1/2011


  20. Bacteria Growing Kit review by Darla L. Martin on 8/8/2011

    We ordered the Bacteria Growing Kit for my son's science fair project. The instructions were good, and we didn't have any trouble getting the agar to "set up". We started growing bacteria within 3 days, so we were very excited. I would definitely recommend this kit!

  21. Be careful with dishes of ager review by Candace Ingle on 6/24/2011

    In trying to explain our test results, we contacted a university professor who made the following suggestions: (1) wear a mask when you are making the ager so that you don't accidentally breathe micro-organisms onto your ager
    (2) make sure that you immediately close up the dishes of ager while they are setting up so that they don't pick up micro-organisms from the air
    (3) be sure not to open the dishes once you see growing organisms and handle the dishes while wearing gloves and a mask (for safety)
    (4) make sure that you order a large enough kit for multiple trials if that is part of the grading rubric for your experiment (we learned this one the hard way and now I am ordering more)
    (5) it may also benefit your experiment to keep a chart of bacteria growth checking the dishes every 8-12 hours noting the colors and numbers of colonies that you see.

  22. Petri Dishes review by Sheri on 5/24/2011

    We ordered the Petri dish kit for my 5th grader's science project, Who Would You Rather Kiss, Your Mom or Your Dog?. It worked very well and was easy to use. We will definitely order something from your website next year.

  23. Dirty Mouth review by ReyAnne Moorehead on 5/4/2011

    This Petri Dishes were easy to make! It was a success the 1st time we tried! We used these in a science fair project to see if our dogs' mouths were dirtier than my child's. I am excited to say that he placed 2nd in his 3rd grade division at his elementary school! Thank you for the part that you played in this!

  24. Growing Bacteria review by Dana on 4/20/2011

    We received the kit just days after we ordered it. After following the directions, we tested the bathrooms at my son's school for bacteria. Very disgusting things began to grow within a week and my son has now decided that hand washing is important! His science fair project is due in two days and we are ready!

  25. Student review by Susan Fischer on 3/15/2011

    Very easy to use product. I grew bacteria from different drinking water sources. I was amazed that I had growth within three days. The was used for an University Integrated Science project.

  26. Bacteria Growing Kit review by Kathy Kruisenga on 1/30/2011

    I am not a biology person and had never worked with agar. The directions were simple and very easy. The students loved this activity. They are submitting it as a science fair project.

  27. great science project review by Nicole Andreno on 1/9/2011

    This was easy and fun for my 9yr old sons science project he loved it

  28. Bacteria Growing Kit-Petri Dishes works great sometimes review by S. Latshaw on 11/20/2010

    Bacteria Growing Kit-Petri Dishes was an easy to use kit. However, in some situations I was unable to get any growth to show and at other times there was heavy growth. Since the procedure used was the same I'm uncertain why there was a difference. I would also like to purchase more agar powder without the petri dishes.

  29. Bacteria Growing Kit review by Kaitie on 11/1/2010

    I was so excited that everything worked out perfectly with my project! I gave a lesson on germs and our immune system. I thought it would be interesting and fun for my class to get the opportunity to see where germs lived the most. So my class swabbed away- they swabbed everything from their cell phones, to the stair railings, to our teachers key board. I came back with the results the following week and we found out what not to touch.

    This is such a fun hands on real life teaching tool, and I will definitely be using it in my classes in the future.

    Steve Spangler Science was great with their customer service. They helped me find just what I needed and suggested the route of shipping I should take in order for it to get to me in a few days- and it arrived on time, and everything was a success!!!

  30. petri dish kit review by Courtney Hocking on 9/12/2010

    The kit contained everything that we needed. The only bad thing about the whole thing is that we wanted to do more! This is only the tip of the iceberg! we tested the cleanliness of the school and we found that the dirtiest place was the teacher's lounge! Thank you ! ! !

  31. Good Science Fair Project review by Amy on 8/17/2010

    I ordered this for my sons 6th grade science fair project. It had clear, easy to follow directions. He enjoyed taking the samples, mixing the auger, and mostly seeing the bacteria growth!!

  32. Very Fun! review by Robin on 8/3/2010

    This was a very fun and interesting experiment! Thanks so much Steve!

  33. Nice product, but not enough agar review by Bob Lambert on 6/6/2010

    The directions tell how much agar to use for the six dishes, but you don't provide enough agar.

    Bob, I'm sorry that you experienced a problem with this kit.  We actually provide enough agar for 12 petri dishes, which allows for mistakes, spills, and the like.  A customer service team member will contact you to discuss this with you.  -- The Steve Spangler Science Web Team

  34. Very Cool review by Erin on 5/11/2010

    My five year old and I had so much fun testing door knobs, remote controls, dog noses, toilet seats, etc...It was amazing to see after a few days how much bacteria (and different types of bacteria) was growing in the dishes

  35. An awesomely gross experiment review by Debbie on 4/19/2010

    This is a creative and excellent science fair experiment that appeals to kids, asks a good question, performs multiple tests, and eventually comes to some disgusting conclusions. What a great way to demonstrate the scientific method, the use of a variable and a control, and the process of making discoveries/conclusions. Amazing job!

  36. Awesome review by Maddy C on 3/13/2010

    Just Awesome

  37. No Double Dipping review by Janet C. on 1/24/2010

    I can't believe how gross this is. The best part is that I could do it at home with petri dishes and the jello stuff. This is a great science fair project idea for my daughter who loves gross stuff.

  38. Great product, could use more agar review by Peggy on 1/12/2010

    We wish there was one extra pack of agar in the bacteria growing kit. Even though your instructions warn of microwave boil-over, it did happen to us, and is probably very common, so we were out of luck. Our alternative was to buy 25 ounces more for the same price as the kit. We think you could have put an extra 5 ounce pack for more value, less disappointment. Otherwise - great product and service. Luckily, our experiment is going forward because we bought 2 kits, wanting 12 samples of (comparing growth of dog, cat, rat, saliva). We now have a compromised 8 samples for the science fair project, with less agar in each dish....

  39. Bacteria Growing Kit review by Paula Symonds on 12/23/2009

    The directions were very clear. The agar set quickly. It made my class of first graders feel like real scientists

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