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Plant Connections Leader's Guide—Lesson 3: What Makes Plants Grow?1

Janice Easton and Deborah J. Glauer 2

The vital needs of a plant are very much like our own—light, water, air, nutrients, and a proper temperature. The relative importance of each of these needs differs widely among plants. The ability of a plant species to spread throughout a geographic area is a direct result of its adaption to the abiotic and biotic components of the area. Although most habitat components act on a plant simultaneously and should be considered together, the lack of one essential component can determine the health of a plant. This factor, whatever it may be, is referred to as a limiting factor. The concept of limiting factors applies to all aspects of a plant's interaction with its habitat. Any factor in the ecosystem can act as a limiting factor. For example, water is important to many species; most species cannot live in desert regions because of lack of water and most cannot live in marshes because of excess water. Extreme temperatures inhibit plant growth in many regions; lack of warmth in winter is a limiting factor that keeps many species restricted to the tropics.

Another limiting factor is often competition from species that use the same resources. Competition is the principal interaction among plants. Plants of the same species are strongly competitive because they have the same requirements for sunlight, water, and nutrients.

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1. This document is 4H360, one of a series of the 4-H Youth Development Program, UF/IFAS Extension. Original publication date May 1997. Revised January 2015. Reviewed January 2019. Visit the EDIS website at for the currently supported version of this publication. For more publications in the 4-H Plant Connections curriculum, go to
2. Originally written by Janice Easton, UF/IFAS Extension Alachua County; and Deborah J. Glauer, UF/IFAS Extension Youth Development Specialist and Plant Science Design Team Leader; additional assistance provided by project assistants Christy Poole and Lynne Schreiber; reviewed and revised by Dr. Sydney Park Brown, associate professor, Environmental Horticulture; Norma Samuel, UF/IFAS Extension urban horticulture agent II, UF/IFAS Extension Marion County; Dr. Paula Davis, UF/IFAS Extension 4-H youth development agent III, UF/IFAS Extension Bay County; and Dr. Joy C. Jordan, associate professor, Department of Family, Youth, and Community Sciences; UF/iFAS Extension, Gainesville, FL 32611.

Publication #4H360

Date:February 25th, 2019

  • Critical Issue: Youth


  • Heather Kent
  • Sarah Hensley