Potting Soil E Fair Projects

Name: Monica
Grade Level 6th

PURPOSE

The purpose of this experiment was to determine how different mixtures of potting soil affected radish growth.  

I became interested in this idea because I am a gardener. I wanted to know what mixtures would make my plants grow faster.  

The information gained from this experiment would be helpful to people at nurseries and to gardeners so they can grow their plants faster and healthier.

HYPOTHESIS

My hypothesis was that the mixture with the most organic matter would grow better.

I based my hypothesis on the book Soil. It says, “Organic matter gives the soil nutrients that plants need. ”

EXPERIMENT DESIGN

The constants in this study were:

•  Species of Plants (Radishes)
•  Seed age/storing method
•  Planted same day
•  Amount of light (fluorescent grow light) 
•  Container size, shape, and material
•  Amount of soil (250ml) 
•  Depth (2 centimeters)
•  Amount of water given to grow (75ml every other day)
•  Time grown (6 weeks)
•  Degree of water 
•  Procedures used

The responding variable in this experiment was the height the radishes grew in centimeters.  
 

To measure the responding variable in this experiment I measured height of the radishes with a centimeter ruler after a six-week period.

MATERIALS

PROCEDURES

1. Buy soil 
2. Buy radish seeds (packages)
3. Get 60 mini pots
4. Get a grow light (florescent light)
5. Put different mixtures of soil in mini pots
A. Mixing the soils
a1. Mix the bag of soils
b. Equal parts of peat moss and cactus soil (group 1a)
c. Equal parts of peat moss and potting soil (group 1b)
d. Equal parts of cactus soil and peat moss (group 1c)
e. 25% peat moss and 75% cactus soil (group 2a)
f. 25% cactus soil and 75% potting soil (group 2b) 
g. 25% potting soil and 75% peat moss (group 2c)
h. Equal parts of peat moss, cactus soil, and potting soil (group 3a)
I. “Monica’s Mixture” 1/4 cup water, 1/3 coffee grounds, 1/3 ground up sunflower seeds, and 1/3 soil (group 3b) 
j. Equal parts of “Monica’s Mixture”, peat moss, potting soil, and cactus soil (group 3c)
k. Peat moss (group 4)
l. Soil for seed starting (group 5)
m. cactus potting soil (group 6)
6. Place radish seeds two centimeter s down in the soil and cover up seeds
7. Put the mini pots under the grow light)
8. Make sure you make the grow light close enough to the plants
9. Water the radishes ONCE every day with 75ml of water (spread the water out evenly with an eyedropper
10. Let the radishes grow for 6 weeks
11. Measure each radishes height in centimeters when they are done growing with a centimeter ruler
12. Put the 0 cm part of the ruler at the beginning of the radish (nearest to the soil)
13. Record which was the longest and which was the shortest
14. Clean up and throw the mini pots away

RESULTS

The original purpose of this experiment was to determine how different mixtures of potting soil affected radish growth.

The results of the experiment were the mixture with cactus soil, potting soil and peat moss grew the tallest. The smallest was the mixture of peat moss, cactus soil, potting soil and “Monica’s Mixture”. It didn’t grow at all.

CONCLUSION

My hypothesis was that the mixture with the most organic matter would grow better.

The results indicate that this hypothesis should be rejected, because the mixture with all of the soils, cactus soil, starting soil, peat moss, and “Monica’s Mixture” didn’t grow at all. Since it had all the soils that would mean it had the most organic matter then the other mixtures. The soils in the one that grew the tallest were equal parts of all three soils, the peat moss, potting soil, and cactus soil. Unfortunately, the mixture didn’t work very well.  

Because of the results of this experiment, I wonder if I would have used different soil types if the plants would have grew taller and I would have had different results. I also wonder if I would have used real soil and not purchased soil.

If I were to conduct this project again I would have grown the plants longer than I did. I also would have used different types of soil and mixtures of soil. I would have used less water to water the radishes.   I would have used better water drainage. I also would have used a different species of plants. I could have sterilized the soil. Abstract