Set up each plant as above, the opaque/dark covering prevents growth. Pour the culture solution in a test tube filled with washed sand.
Use five test tubes one contains the first culture solution contains all the minerals (phosphorus, nitrogen and potassium) necessary for healthy plant growth. The other test tubes have two minerals except one of each. For example the second test tube could have potassium and phosphorus but no nitrogen and so on. The last test tube should have only distilled water.
Observe the seedlings over a period of several weeks.
Examine the seedlings on a daily basis and take note of the following:
the root length of the plants, the length of the plant shoots, the colour of the leaves and the number of leaves.
Make sure that the seedlings have enough solution by constantly adding distilled water whenever necessary, do not use tap water as it contains the minerals naturally.