Plants and Water

Time frame: one week
Space needed: sunny window sill
Objective: To observe the effect of various soil moisture conditions on plant health.
Materials needed:
  • green bean seeds
  • small paper cups
  • potting soil
  • pea gravel or crushed rock
  • salt
  • water
Introduction:
Plants require water to grow. They get their water from the soil. Different soil types hold different amounts of water for the plant; potting soil holds more than gravel does. The plant will run out of water faster in the gravel than the potting soil.

A serious problem in Texas vegetable farms is salty water. Irrigating with salty water can limit the plant's ability to take up water. The plant may in fact wilt just like it would in a dry soil.

Methodology:
  1. Punch small holes in the bottom of each cup.

  2. Put potting soil in 3 cups and gravel in 1.

  3. Plant 2 seeds in the 4 cups.

  4. Treatments will include:
    Cup #1 - potting soil, seed and water with 1/2 cup of water
    Cup #2 - potting soil, seed and water with 1 teaspoon of water
    Cup #3 - potting soil, seed and water with 1/2 cup salt water solution (1 teaspoon salt and 1/2 cup water)
    Cup #4 - gravel, seed and water 1/2 cup of water
    Note: let excess water drain out of holes in bottom of cups.

  5. Observe the seed/seedlings twice a day and note any differences between treatments. Expect to see the seedling in the gravel to run out of water the fastest, wilt and die. The seedling water with the salt water solution should also wilt and die quickly due to a lack of the ability of the plant to take up water from a salty soil environment. Seedlings in Cup # 2 will then wilt from lack of water, followed by those in Cup #1.