Horticulture, or the study of plant propagation and cultivation, has been around since the first century according to the History of Horticulture at Ohio State University. Through the years horticulturists have studied soil types, classified plant life and learned about what diseases and pests effect plant growth. Gardening today is easier because of the study of horticulture and the methods available to gardeners developed over the years through trial and error.
Soil quality involves the ability of the soil to sustain the life of the plants it contains. It is important to know the pH (how alkaline or acidic the soil is) of the soil before planting because pH requirements vary from plant to plant. According to the Garden Helper, lime is added to soil to increase the alkalinity while sulphur is added to increase acidity. Soil is also broken into types. The University of Illinois states that soil types are determined by how much silt, sand and clay are present. Loamy soil is a balanced combination of all three and is the most desirable type of soil for gardening; it retains moisture, but drains well.
Plants require varying amounts of light in order to grow to their fullest potential. Without light, according to Gardening Know How, "a plant would not be able to produce the energy it needs to grow". Plants need lights that are on the blue spectrum and this includes daylight, commercial grow lights and fluorescent lights. Plants labeled full sun need eight or more hours of light a day while some plants labeled shade, or low sun, can succeed with a few hours of light a day.
Phytopathology is the study of plant disease according to the American Phytopathological Society (APS). The study of plant disease is always changing as scientists work to develop new ways to combat plant disease. The APS states that pathogens such as bacteria, viruses and fungi can cause plant disease as well as pollutants in the air or nutritional imbalances. According to the APS, "Plant diseases may be managed by altering the host plant, the pathogen, and/or the environment. Examples include growing resistant plant varieties, planting pathogen-free seed or stock, applying a biological control agent, modifying environmental conditions to decrease disease, and using plant medicines that inhibit or kill the pathogen without harming the plant or the environment."
Some plants thrive in certain areas, despite a large insect population. Genetic engineering technology has been used to create plants that are more resistant to insects. The most widely used genetically engineered plants are cotton, which has been engineered to be resistant of caterpillars and maize that is resistant to root worms. John A. Gatehouse from the School of Biological and Biomedical Sciences, Durham University, states that genetic engineering has lowered pesticide applications and lowered the cost of raising crops.
The United States Department of Agriculture has developed a zone hardiness map. This map divides the country into regions of common temperatures. Plants are classified as hardy through certain zones and gardeners can learn quickly what will grow and what will not survive in a garden through this system. The development of a zone hardiness map and the classification of plants has made it easier for gardeners to grow successful harvests.