Hypothesis:

We can produce enough food to feed one astronaut for one week.

We think plants that use a little space or grow a lot on one plant, like lettuce or tomatoes, will grow better than plants which need a lot of space, like corn.

Procedure:

Materials for set up:

1 plastic container, 8-12" deep, about 30" x 36"
(We used an under-the-bed blanket box from Target.)
1 immersible evaporative cooler pump, 1/2 horsepower
(We used a Little Giant with a fitting to connect to 1/4 inch plastic hose tubing)
2 plastic planter trays, 10" x 28"

6 feet of copper tubing, 1/2" diameter
6 feet of plastic tubing, 1/2" diameter
1 small basket to put over the pump and rest the boxes on, for drainage
1 sheet of plastic small mesh screen, as used in craft projects
drill with a 1" drill bit and a 1/16" drill bit
zip ties or wire ties
small tube of clear silicon
lots of patience

Materials for growing:

1 box of Miracle Gro
1 large bag vermiculite
1 large bag of pebbles, as used in an aquarium
variety of seeds to plant (corn, peas, lettuce, radishes, fast plants)

Note: small seeds need to be started in the mix used in the trays, but in small containers, like ice cube trays, and then transplanted to the boxes. Otherwise, the force of the water will wash them away.

Directions for assembling hydroponics lab:

1. Cut the copper tubing in half. Then use a pencil to mark a straight line down any side of the tube. On the line that was drawn use the 1/16 drill bit and drill holes every 2-3 inches along the line. Make sure to leave 5 inches on either side to connect tubes later.

2. Drill a 1 inch hole in each corner of the planter and cut a piece of the plastic mesh to fit over each hole. Make sure to leave a little overlap so that you can silicon glue them into each corner. This mesh will prevent the gravel media from going through the holes and causing clogs in the system.

3. Drill a couple of 1/16 inch holes on the top of the planters to screw them together. Screw them together side by side. After planters are attached, place them in the bin to make sure they fit. Both planters should fit inside the bin and be elevated off bottom about 5-6 inches.

4. Drill two more holes in the center of the planters to connect your copper pipes with the zip ties. These holes may vary because of the shape of your planters. The key here is to think water proof. Make sure that the holes in the copper pipe are pointing into the planter or you might end up being wet or wetting your room.

5. After pipes are attached, connect clear plastic hoses to pipes and pump. Do it in this order:

6. Add water and make adjustments as necessary. Be sure to check that all seals are water tight before leaving equipment running. Good luck! Happy growing!

Directions for planting the seeds:

We will plant the small seeds, like the radishes, the lettuce and the fast plants in ice cube trays to begin. We will fill the trays with the medium from one planter box. We have to make sure they stay wet.

We are especially interested in seeing how the fast plants grow. These are the seeds we raised earlier in the year when we wanted to find out how plants grow. We hope our seeds are good and will grow.

We will plant the large seeds, corn, string beans and peas, directly in the box. They are too big to get through the screening and wash away. Plus we think they can withstand the force of the water. We will not plant them directly where the water falls.

The water will be turned on twice a day for a few minutes to irrigate the plants.

We will keep track of how fast the plants come up and compare the time to what the package says is normal. We know that fast plants should come up within 2-3 days, from our previous experience with them.

We are going to ask the Kindergartners and third graders how fast their beans came up, so we can compare real life experiences in our growing area.

Observations:

First observation: The water comes out of the holes in the copper tubing really fast! We think we should have gotten a motor with different speeds on it so we could slow the water way down when the plants are small and speed it up when they are well rooted.

Second observation: You should not use anything too small. It clogs up the mesh from which the water should be draining. Next time, we will add a 2 inch layer of small pebbles and then the vermiculite. The back box is draining properly, the front box is not. We have emptied all the water, including the small sandy junk, and are ready to start the boxes again. If the front box still does not drain, we will only plant in the back box. Mrs. Nixon asked us if we thought a real space station might have problems like ours. We are thinking about that.

Third Observation: The fourth graders grew plants in a wonderful medium that we think might have worked better for our project. In the beginning, it looks like rock salt. Then you add water. It absorbs the water. It then feels and looks like clear jello. Mrs. Nixon wouldn't let us taste it. One bad thing we thought of is that this might also go down through the holes, since it is soft. It might mess up the motor.

Fourth observation: We thought we had broken the motor. It worked off and on all day. It sounded like it was sucking air. We turned it off. After we emptied the water and refilled the container, we plugged the motor back in. It wouldn't start. Mrs. Nixon noticed the wall plug has a reset button. Our refrigerator was not running either. We pushed the reset button and the motor started. We were happy.

Fifth observation: The peas grew tall really fast! We think we should not plant anything in with the peas. They will keep the other plants from getting enough light. They also are sending out curly little things that need something to grab onto. We will need to put a piece of dowel rod across the tub for them.

The fast plants seem to be growing more slowly than they did in dirt. We think this might be because the light is farther away. It might be because they were developed to grow in dirt. We aren1t sure.

We thought we could grow enough food for one astronaut for one week. Now we are wondering if he or she wouldn1t get a little hungry! First of all, we are growing only 4 vegetables. We think more variety would be necessary, and much more room on the space station or space shuttle. We don1t think there will be enough for one week1s meals - 21 meals.

We are still thinking that the rock salt/jello substance might be a better growing medium. We would not have to irrigate the plants, just make sure the medium stayed wet and in the jello state. Then the trays could be put in any spare space, or even hung from the ceiling and not depend on motors and a water tray. You could even use regular plant pots.

All the plants seem happy in the hydroponics environment. They are all growing well, and every seed came up, though they didn1t all come up at the same time, even the same kinds of seeds. So it would be a choice between what you like to eat, and what takes a lot of room or a lot of time to grow.

We think that there is probably some oxygen being produced by our plants, and we are wondering how we could test the air around the plants to find out. If we are right, maybe this could help in the air recycling system of the space station or space shuttle.

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