Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
Is MiracleGro the Best Fertilizer for Impatiens wallerana?
Michelle Huynh and Jiwon Park
Department of Psychology and Foreign Language
Saddleback College
Mission Viejo, CA 92692
Fertilizers are used to enhance the growth and development of a plant. Fertilizers
may contain nitrogen, potassium, and soluble potash, which provide nutrients for growth.
Well-known fertilizers, such as MiracleGro, are considered to make plants healthy. The
hypothesis suggests that when the group of Impatiens wallerana is given MiracleGro All-
Purpose Liquid Fertilizer, the plants will grow at a faster and healthier rate than the
groups that are given other or no fertilizer. In this study, the plants were organized into
three groups: MiracleGro, Liquinox, and control. The groups were given the same amount
of fertilizer and water for five weeks. Each plant was measured once each week and at the
end of five weeks, the chlorophyll from the leaves was extracted and measured at two
different wavelengths. The Liquinox group had the highest chlorophyll concentration
(p=0.009, unpaired t-test); however, there was no difference in the stem length change
among the three groups. The results show that MiracleGro is the most harmful fertilizer if
given a large amount due to its high nitrogen content compared to Liquinox.
Introduction
Fertilizers are compounds that are used to help
plants grow and develop. Plants can uptake fertilizers
by the roots or through the leaves. Fertilizers can be
organic, composed of naturally occurring elements, or
inorganic, manmade chemicals. The three major plant
nutrients are nitrogen, phosphorus and potassium,
which are the components provided by fertilizers.
Typically, the presence of nitrogen compounds in the
soil is essential to plant growth. Thus, nitrogen plays
important roles in providing proteins, hormones,
chlorophyll, vitamins and enzymes. Phosphate (P 2 O 5 )
is integral for photosynthesis, protein formation and
flowering. An absence of phosphate can lead to
delayed growth and poor flower production. Soluble
potash (K 2 O), or potassium, facilitates in the
production of sugars, starches, carbohydrates, in
protein synthesis and cell division in plants. It aids in
the absorption and conservation of water, turgidity of
plants and the enhancement of flower color. A lack of
potassium will result in unhealthy leaves (Milius,
2007).
Chlorophyll is a pigment that gives plants its
green color. The more chlorophyll content in a plant,
the higher the rate of photosynthesis will be and the
darker the color pigment will be (Milius, 2007).
Based upon many advertisements and
commercials, one can conclude that MiracleGro is the
most efficient fertilizer compared to generic brands,
such as Liquinox. Therefore, MiracleGro is the best
fertilizer for plants compared to Liquinox and no
fertilizer at all. With the addition of fertilizer, plants
should have more chlorophyll, and thus higher growth
rates.
Materials and Methods
Eighteen plants of Impatiens lipstick, one of
the garden cultivars of Impatiens wallerana, purchased
at Home Depot in Mission Viejo, California on
October 7, 2007, were planted with Premier Pro-mix
general purpose growing medium potting soil and
separated into three groups: Control, MiracleGro, and
Liquinox. They were planted in Science and Math
greenhouse at Saddleback College on October 8, 2007.
Each pot was watered 60 mL. Every week, each
individual plant was watered 200 mL of water twice a
week for three weeks.
Every Friday, each plant of the MiracleGro
group received 3 mL of the MiracleGro All-Purpose
Liquid Fertilizer plus 200mL of water. Each plant of
the Liquinox group received 3 mL of Liquinox Fish
Emulsion Plant Fertilizer plus 200 mL of water. Each
plant of the Control group only received 200 mL of
water, with no fertilizer. The longest stem of each plant
from all three groups, which was marked with a string
loosely tied around on the first day, and measured at
the end of each week to chronicle the growth of the
plants. In addition, a photograph was taken of each
group of plants in order to record how the plants were
developing and changing, in regards to the fertilizer, or
lack thereof.
62
Saddleback Journal of Biology
Spring 2008