Science Models
Science Fair Projects

Published on Sep 12, 2023


The objective: Fertilizer in runoff increases algae growth, and I want to determine which fertilizer will decrease the amount of algae growth in water. I believe a fast acting three-ingredient fertilizer will cause the most algae growth, and a time-release fertilizer will cause the least algae growth because a time-release fertilizer only lets off a small amount of nutrients at a time.


Three types of fertilizer were used: 14-14-14 time-release, 12-0-0 fast-release (one-ingredient), 15-30-15 fast-release (three-ingredient).

A mixture of pond water and distilled water with a precise amount of fertilizer was added to twelve 1-pint glass jars.

The jars were covered with cheesecloth and set in sunlight for 35 days.

After 35 days the algae was scraped onto separate coffee filters, and weighed while wet with a gram weight scale.


The one-ingredient fertilizer grew the most algae, 1.3 grams. The fast-acting three-ingredient fertilizer grew 1.2 grams.

The time-release fertilizer resulted in the least amount of algae growth, .4 grams.


The time-release fertilizer grew the least algae, as I hypothesized.

I would recommend this fertilizer for gardening to reduce algae growth, but I would research in the future how well it helps plants grow.

The one-ingredient fertilizer grew the most algae, and the fast acting three-ingredient fertilizer grew less algae, but only by .1 gram.

This experiment is to determine which fertilizer will grow the least algae in water

Science Fair Project done By Neil D. Tennyson