Does this experiment make sense

A: Problem: Does the pH level of soil affect plant growth?

• Materials- Bean plants, pH testing strips, aluminum sulfate, garden lime, wood ash, potting soil, water, meter stick, notebook, and four planting pots.
•Procedure-
1. Fill the planting pots halfway with potting soil.
2. Plant one bean seed into each pot. Plant the seeds about two centimeters below the soil surface.
3. Add a tablespoon of aluminum sulfate into one pot. Mix with soil. Find the pH using a testing strip. Label the pot ‘Aluminum Sulfate’ with the pH level. Record pH level in notebook.
4. In another pot, add 1/8 cup of garden lime into the soil. Mix with soil. Measure pH level. Record in notebook.
5. In another pot, add 1/8 cup of wood ash into soil. Mix with soil. Measure pH level. Record in notebook.
6. Use the remaining pot as a control.
7. Water each plant every two days. Keep the plants in same location.
8. Measure your plants every day and record the height in centimeters.

I agree that the additives should be added before planting the seeds. Also, additional soil should be added to the aluminum sulfate and control pots so that each pot has the same total amount of soil. Sounds good overall.

Of course you are only testing the effect of soil pH on bean plants. If you want to go further, try an additional species or two.

It makes sense but it would be more reasonable to mix the chemicals into the soil before planting the seeds.