The Effect of Different Potting Soil Mixtures on Radish Growth

Researched by Monica S.
2003-04

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. ”

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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 manipulated variable in this experiment was the different mixtures of potting soil.

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.

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MATERIALS

QUANTITY ITEM DESCRIPTION
75ml amount of water per day
1 set of mini pots
2  Packages of radish seeds
1  Florescent grow light
1  bag of peat moss 
75ml soil 
1 bag of cactus soil
1 bag of potting soil for seed starting
1 Eyedropper (to water plants)

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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

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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.
 
 

See my data table and graph below.

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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.

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RESEARCH REPORT

Radishes
Radishes are a food and a medicine. They have lots of nutrients.   The common radish is a fast growing, annual, cool-season, root vegetable.   The seed germinates in three to four days. Good quality radishes can be produced on either mineral or muck soil. Preferred planting dates are early spring and August, but suitable crops can be obtained from plantings made from April through August in certain areas. Radishes remain in prime condition only a short time, especially in warm weather.   Radishes have a variety of uses. They are used in medicine and as a food. The roots stimulate the appetite and digestion, having a laxative effect on the intestines and it stimulates the flow of the bile.   Radishes are used in the treatment of intestinal parasites. The leaves, seeds and old roots are used in treatments of asthma and other chest problems. The juice, in the fresh-leaves is diuretic and laxative. Radishes are crushed and used as a poultice for burns, bruises and stinky feet.   The root is best harvested before the plant flowers. Radishes show anti-tumor activity. Radishes can be used in salads, stir-fry, and many other foods. They can also be eaten plain.  
 

Agriculture
Agriculture is the most important industry in the world. It provides us with pretty much all of our food. About half the world’s workers are employed in agriculture. Agriculture is one of the worlds oldest industries. It began to develop over 11,000 years ago in the Middle East. Before developing agriculture people had to gather wild plants, fish, and hunt to find food. They had to search for food continually, which left them little time for other activities. As agriculture began to increase fewer people were needed to produce food.
 

Photosynthesis
Photosynthesis is a physico-chemical process. Both algae and photosynthetic bacteria use sunlight energy to drive the synthesis of organic compounds. Other types of bacteria use light energy to create organic compounds but do not produce oxygen. The fossil fuels are currently being burned to create ancient photosynthetic organisms that produced energy we use today for human activity. Although photosynthesis occurs in cells or organelles that are typically only a few microns across the process has a huge impact on the earths’ climate. The knowledge of photosynthesis is essential for understanding the relationship between living organisms and the balance between life on earth. The overall equation for photosynthesis is simple. To produce a sugar molecule such as sucrose, plants require nearly 30 distinct proteins that work within a complicated membrane structure.   The formula for photosynthesis is 6 H20+6 CO2=> C6H12O6+6O2.  
 
 
 
 
 
 

Types
The most common radishes are, Belle Glade, Fuego, Red Cheriette, and Cherry Belle. Jumbo varieties, which can grow to the size of a young beet, include Champion, Red Crunchy, and scarlet Globe Special. Varieties raised for bunching are Revoso, Saxfire, Red Baron, and Galahad. Snow white or creamy white have the same crisp texture and pungent flavor as the red-and-whites. They are most commonly elongated, growing to about 15 centimeters. Snow Belle is a globe-shaped Jumbo variety. Long Black Spanish is one of the large black icicle types.   There are also oriental types of radishes. Daiko, a Japanese radish is the best known of the oriental types. It is white fleshed and long and tapered like a bunching carrot, but thicker. Size is the main difference between this radish and White Icicle. The Daiko grows as long as 45. 7 cm. Chinese lo Bok is white fleshed, sweeter in flavor than all the others and more cylindrical shape. A Korean radish is similar to the daiko, but smaller.

Soil
Soils are made up of organic material and minerals. Organic matter comes from dead plants and many other minerals come from the rocks underground. These are referred to as bedrock. Soils are made up of different layers because plants grow on top of the ground, and rocks are found underground.   The types of soil that forms in a region depend on the climate. Minerals in soil are just broken down pieces of rocks that have been broken down by weathering. Weathering occurs after many years by wind, rain, ice and high and freezing temperatures. The plants help the soil building process. When plants die and decay bacteria lives on the leaves and plants. Humans get nutrients from soil. Animals eat plants, plants live in soil, and humans eat animals. The formation of soil takes a long time. Soil covers most of the land’s surface.   Microbes cause dead organisms to decay. Minerals and organic particles in the soil are called soil particles. Plants and animals live in pore spaces in the soil. Most humus is black and dark brown. Humus holds large amounts of water. More than 20% of the particles in soil are organic.

Summary
To grow plants you have to have soil. Plants can’t grow without organic matter and that’s what soil has. The soil type matters when you are growing plants because it may have things in it that could kill your plants if the soil is wrong. The best type of soil to use would just be regular potting soil.
 
 
 
 
 
 
 

 
BIBLIOGRAPHY
 

Baxter, Roberta. Hugh Bennett, Soil Scientist 4-01-03
http://elibrary. bigchalk. com

Burnie, David. “Plant” New York: Alfred A. Knopf Inc.

Hershey, David R. “Plant Biology selah schools, science project, SIS science, S.I.S. Soil and Fertilizers ”, pages 93-101, John Wiley and Sons Inc.  

Hershey, David R. “Plant Biology selah schools, science project, SIS science, S.I.S. Introduction” Pages 3-7, John Wiley and Sons Inc.

Johnson, Nadine. “What is Soil Made of” 4/30/03 http://www. askjeeves. com 

Johnston, Taylor. “Soil” World Book Encyclopedia 2002

Lansing State Journal. “What is Soil Made of” Lansing State Journal http://www. askjeeves. com 

“Soil” ENCARTA Encyclopedia Deluxe, 2001.

Trotter, Don. “Your Garden Plants Need Minerals Too” copyright 2000 http://www. askjeeves. com 

Winckler, Suzanne, Rogers, Mary. “Soil” Minneapolis: Lerner Publications Company

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ACKNOWLEDGEMENTS

I would like to thank the following people for helping make my project possible:

  •  My parents for always being there for me when I needed help and for helping me choose my topic and helping me get my materials.  
  •  Mr. Newkirk for helping me along the way
  •  Mrs. Helms for helping me when I needed it 
  •  My friends for putting me in my place when I needed it (All the time!!!!!)

 
 

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