How does the level of solutes (salt) in water affect plant growth over twenty five days?

Table: 10
Experimentation location: Home
Regulated Research (Form 1c): No
Project continuation (Form 7): No

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Project files

Research Plan:

  1. Use eights paper cups and fill each pot with soil all the way to the top of the cup
  2.  Add one seed of the pea plant to each cup (dig one inch down to place the seed and then cover the seed with dirt)
  3.  Put all eight cups into an area that gets sunlight almost all day long
  4.  Put two tablespoons of tap water in two of the cups and label them control cup #1 and #2
  5. Put a smidgen (1/32 teaspoon) of salt into one of the tablespoons of water and pour it into two of the other cups and label the cups Cup #3 and Cup #4
  6. Put a pinch (1/16 teaspoon) salt into one of the tablespoons of water and pour it into two more cups and label the cups Cup #5 and Cup #6
  7. Put a dash (1/8 teaspoon) of salt into one of the tablespoons of water and pour it into the last two cups and label the cups Cup #7 and Cup #8 
  8. Repeat this every other day and stop if plant looks like it’s wilting 
  9. When you see growth in one of the cups and then start measuring with a ruler how much the pea plants grow per day
  10.  After 25 days has passed stop and collect your data and make a bar graph


  • 8 pea plants 
  • 8 separate pots or paper cups (all identical)
  • Potting soil
  • Water
  • Measuring tape
  • Tablespoon
  • A measurement tool for a smidgen (1/32 teaspoon), pinch (1/16 teaspoon), and dash (1/8 teaspoon)   


Questions and Answers

1. What was the major objective of your project and what was your plan to achieve it? 

The main objective of my project was to see how the amount of solutes (salt) in water would affect pea plant growth over twenty five days. My plan to achieve this was to conduct an experiment where I would grow two pea plants with no salt, two with low levels of salt, two with medium levels of salt, and two with high levels of salt. The goal was to see how plants with all of the same variables, with the exception of the salt level, would grow and how the growth would vary.

    a. Was that goal the result of any specific situation, experience, or problem you encountered?  

The goal of this experiment was to see how plant growth is affected by the amount of salt that goes on the sidewalk during the winter to thaw ice and the amount of salt water that goes on plants during hurricanes affects plant growth and germination. I chose this because I figured that plants must somehow be affected by salt on sidewalks in the winter and I wanted to know if we should find an alternative to using salt on the sidewalks because it could harm the plant life around it. 

    b. Were you trying to solve a problem, answer a question, or test a hypothesis?

I was trying to test a hypothesis, which was that the more salt there is in water, the more it would stunt and delay the growth of the pea plants, and as a result, the plant with the least amount of salt would grow the fastest. I believed this because I know that salt in water takes away the amount of water that the plant takes into its roots, and then delays the growth.

2. What were the major tasks you had to perform in order to complete your project? 

During the process I would have to water and measure the plants everyday making sure that I didn’t over water the plants as well as make sure that I put the same amount of salt and water in each plant per day so it wouldn’t mess up the experiment. I also had to measure the plants and then make sure that I recorded all the data I had collected during the experiment.

    a. For teams, describe what each member worked on.


3. What is new or novel about your project?

Something new and novel about my project is that I have never done an experiment before including the growth of something, or an experiment that involved plants at all. 

    a. Is there some aspect of your project's objective, or how you achieved it that you haven't done before?

I haven’t done an experiment before that was continuous over many days. Before my experiments were always able to be completed within an hour. This time the experiment I conducted took over three weeks, which is something I am not used too. It also required me to be really determined and attentive to this experiment because if I didn’t measure one of the plants or I forgot to water them that would greatly affect my results of the experiment.

    b. Is your project's objective, or the way you implemented it, different from anything you have seen?

I haven’t ever seen another experiment that has to do with how salt specifically affects pea plant growth for an amount of time, so it does seem different to what other experiments I have seen before. 

    c. If you believe your work to be unique in some way, what research have you done to confirm that it is?


4. What was the most challenging part of completing your project?

The most challenging part of this experiment was that some of the pea plants with salt in the water didn’t have enough time to grow and the salt stunted their growth too much so the plants took a while to grow or they just didn’t grow at all. That was challenging because it affected how I collected my data.

   a. What problems did you encounter, and how did you overcome them?

A challenge I had encountered during my project was when the plants were not growing fast enough I had to just continue on with the experiment and hope that the plants that were only buds would grow in time. I also had a problem with the control plants because they had begun wilting about halfway through the experiment and I realized that they were being given more water than they needed so I had to decrease the level of water that I was giving them.

   b. What did you learn from overcoming these problems?

I learned that the salt was taking in a lot of the water that the other plants had and since the control plants didn’t have any salt in their water to suck up some of the water so they were being over watered. This means that the plants with salt in the water did have an effect on the growth of the plants and the amount of water the plants were getting access to.

5. If you were going to do this project again, are there any things you would you do differently the next time?

If I were to do this experiment again I would have begun growing the plants earlier than I did so the plants could have more time to grow so I could see the difference of growth more clearly. And I also would have put less salt in each of the plants' water because I feel as though the salt greatly stunted the growth of each plant, especially the ones with the highest levels of salt in their water.

6. Did working on this project give you any ideas for other projects? 

This experiment gave me the idea to see how the level of salt in water affects the amount of stomata on the plant. This experiment would be similar to the one I’m currently conducting except instead of measuring and comparing the growth I would compare the stomata count on different plant leaves.

7. How did COVID-19 affect the completion of your project?

COVID-19 did not affect the completion of my project.