Science Buddies: "Ask an Expert"

What suggestions would you have for doing an experiment with hydroponic plants? Where could you find information on the needed nutrients....?

Thanks,
LB

Hi there,

I suggest performing a Google search on your terms (hydroponic plants nutrients) or go to answer.com.

Here's one webpage I found while using these search terms.

http://www.ext.vt.edu/pubs/envirohort/4 ... 6-084.html

If you have more specific questions, please feel free to post them.

best of luck,
Linh

My Son and I did a hydroponic Science Fair project last year. We had input from several great sites, books and even Disney World's hydroponic group.

Whenever we did a search on hydroponics on the net, we came up with hudreds of sites. We found those that appear to specialize in selling products proved to be the best source for equipment. One even had a complete Science Fair experiment kit.

After much research, we selected growing basil and cilantro as they were both reported to be excellent hydroponic plants...they were.

Our project was to explore the different growth rates of hydroponic vs. soil plants started from seeds.

We made daily measurements of height, number of leaves, color comparison, etc. We made weekly measurements of nutrient chemistry, Carbon Dioxide and temp/humidity.

We created a small greenhouse in our livingroom that allowed us to limit external factors.

This would be a great class experiment and could address phases of growth, soil nutrients, polution, effect of climate, farming alternatives, even global warming. Very hands on with noticable results. And, after a year, we still have an awesome bumper crop of fresh basil growing.

Let me know if I can be of any more help.

Bill

Bill,

Sounds like this project worked well for you. We only have 3 months max. How long did it take you to grow the basil and the cilantro? Also, how did you make weekly measurements of nutrient chemistry, Carbon Dioxide and temp/humidity? We need to research this. Were you able to find a "hydoponic recipe/solution" for these plants on the i-net? Any help you could give would be appreciated.

Thanks,
Linda

Linda,

The project went very well. We both learned quite a bit, and my son really learned about keeping lab notes! And I learned much of patience.

We actually concluded the experimental data on the 38th day. From seedlings, on day 38, plants were very mature with an average of 22 leaves and 145 cm - and 80 leaves and 154 cm for hydroponic Basil and Cilantro leaves/height respectively and measurably less for the soil plants. So, I am sure you would have plenty of time to structure and conduct the experiment.

Weekly measurements of nutrient chem was done with pH strips as you are looking to maintain as set neutral pH. The solution itself is aerated and kept at a fairly consistent volume. Nutrients are consumed and do not concentrate in that short of a time.

Carbon dioxide measurements were made using a CO2 test kit I purchased online. The greenhouse was sealed so CO2 and O2 were different then outside the enclosure. Sample air is taken into a large syringe and it is expelled over a CO2 test strip. Pretty easy. It reads much like a litmus test. There is an optimum O2 and CO2 levels which were easily maintained.

We recorded everything on paper and then transferred to Excel. Nice learning experience both for Excel use and statistical analysis and chart making.

We purchased everything from Atlantis Hydroponics http://www.atlantishydroponics.com/index.html and were happy. They also have a Science Fair Project Kit not listed that you can ask for which worked great for us. They also have a section suggesting an approach to a science fair project at http://www.atlantishydroponics.com/sciencefairs4.html . We didn't use the technique they suggested, but got good ideas.

We measured height with a metric ruler, and took pictures of the plants, leaf structure, roots, and height (plant against ruler) for our lab notes.

There are literally thousands of sites to use as reference...caution many are to support home marijuana growing.

Disney world has a great hydroponic area and an exhibit (Behind the Seeds). They were both an inspiration and provided some good input for additional research info.

We developed a number of sheets that were used every day to record growth and ensure the CO2, nutrient solution, and temp/humidity were recorded and maintained. Let me know if any of these would help and I would be happy to email as a sample.

All in all, this was a good if not intense project. It requires daily attention and some discipline. In the end, good lessons for all and you will have a wonderful time enjoying the fruits of your labor. We still have bumper crops of Basil!

Let me know if I can help further and certainly let me know how your project goes. Good Luck!

Bill,
Thanks for the info. My son likes this idea and I think he will pursue it. Since you offered, I do have a few questions:

He is High School level and will probably need to build or put together the growing system. Because of the expense, we won't be using a greenhouse although I think that is an excellent way to grow things. So, what type of grow light did you use? We've got a 33 watt fluorescent plant light from a previous experiment that that I'd like to use but not sure if it is enough light.

Aslo, regarding comparing the plants grown in soil--What type of fertilizer did you use and were you able to determine that these plants grown in soil were given the same (quantity) of nutrients as those grown without soil? He'll probably stick with the basil or cilantro since these can be grown in a short period of time and per your experience.

Thanks. If there is a site online or a book that your son found particularly helpful, please let us know.

LB

Glad to hear that things are coming together. I'm sure your son will learn a lot and if you like basil & cilantro...get ready for a treat!

Everything we read, and certainly our experience, suggests that having a controlled environment is critical to this experiment being successful. That means temp & humidity must be controlled and maintained much higher than people like to have around them. So, I suggest he revisit the idea of abandoning the greenhouse. Understand that we built a greenhouse that lived in our living room for a few months for under $20. It worked as well as any other greenhouse could have.

We started with a card table; two 6 foot 1" x 2" pine boards; and a roll of black plastic drop cloth (the thickest kind we could find); some heavy packing string; and a 3 foot fluorescent light; a small space heater; a small humidifier; a roll of duct tape (of course ) and a temperature/humidity meter.

We first spread out some of the black plastic as a floor for our greenhouse. We figured spills were likely, and we didn't want to take a chance.

We placed the card table on the plastic drop we laid out and set the 2 1x2 pine boards parallel across the top of the table. We secured them to the legs with the packing string.

We then laid the black plastic drop across the table to that all sides, front & back were covered. Essentially, we build a tent. The boards were used to extend the length of the tent to 6 feet rather than the square 4 foot card table. I think you will also find the 6 feet of space necessary. It worked great for us.

We tucked the plastic under the card legs, and secured everything with duct tape. We had created a light-tight, 'greenhouse' that was isolated from the outside air.

We then hung a 3 foot fluorescent light from under side of the card chair, securing it with the string to the 6 foot pine strips laid across the top of the table. It was a 2-bulb lamp with plant grow bulbs in it, and we needed every bit of the light. We could have used more. According to the books we read, and our experience, a high intensity lamp would be best, but they were pretty pricey for us. We read, and found, that we needed to keep the bulbs not more than 6 inches away from the growing plants in order to supply them with adequate light.

With the structure complete, we added the humidifier (keep it toward the front so filling is facilitated) and the heater. You need to maintain a consistent high humidity, warm environs for maximum growth. Temps and all are given in the books or on-line.

Inside the 'greenhouse' we laid the lid of a plastic storage tub down as a hard floor to keep our plants from tipping over. On that we set our soil pots as well as our hydropinc system. The light was suspended directly overhead and kept about 6 inches from the top of the plants.

You can't give the same quantity or type of nutrients to both the potted plants and the hydroponic plants, as they have different requirements. We used a regular potting soil fertilizer for leafy plants at the recommended concentration and made sure (recording when we did so) that all the soil plants were watered regularly.

The hydroponic system uses a special medium and an air stone connected to a fish tank air pump to keep the hydroponic solution oxygenated and stirred. It worked great. We got all of our hydroponic equipment, test equipment, nutrients, reference book, and hydroponic system from Atlantis Hydroponics (mentioned above). I'm sure there are hundreds of other suppliers, but I can vouch for them. They were helpful and had everything we needed (except the seeds)!

I have some pictures we took throughout the experiment that show how we set up and some of our results. If you are interested, give me your/an email I can send them to.

Best of luck, Linda, I'm sure your son will do great. Please let me know if I can help in any way.

Bill,
Yes, we'd appreciate any pictures of the set up... That could be really helpful. Especially, did you have any area (clear) where you could see the plants in order to check on them daily? Wonder about lining this greenhouse with aluminum foil to better reflect the light. What do you think?

Saturday, we drove to Athens, GA to go to one of the Atlantis Hydroponic stores just to see some hydroponic set ups. Person there was very helpful but acted like we could keep it simple- no greenhouse, said not to worry about checking anything but the pH, suggested a drip system for the basil and did not think any oxygen type generator would be needed for basil. Still, I'm sure the greenhouse would be more successful. They had built an in-store greenhouse and grown these enormous spinach plants from seeds in only 3 weeks!!! Conditions in the greenhouse must have made them thrive so quickly.

Thanks,
LB

I sent a series of photos to your email. Let me know if you got them ok. Best of luck on your project.