Basic Open Pollinated / Heirloom Vegetable Garden Plant Requirements

Many factors come into play to determine whether or not a garden plant will perform well for you. Each kind of garden plant has its own needs and requirements. Some plants, like the dandelion, are tolerant of a wide variety of conditions, while others, such as the pink lady slipper orchid, have very exacting requirements. Before you spend the time, effort, and money attempting to grow a new plant in your heirloom garden, it is best to do some research to learn something about the conditions that the heirloom plant needs to grow properly.

Here is a brief description of some of the environmental parameters that influence plant growth:

Light

Light is the energy source for vegetable garden plants. Cloudy, rainy days or the shade cast by nearby plants and structures can significantly reduce the amount of light available. Shade adapted vegetable garden plants cannot tolerate the bright light of full sun. Plants survive only where the amount is within a range they can tolerate.

Day length

Day length is usually the most critical factor in regulating vegetative growth, flower initiation and development, and the induction of dormancy. Plants utilize day length as a cue to promote their growth in spring and prepare them for the cold weather. Many plants require specific day length conditions to initiate flowers.

Temperature

Heirloom garden plants grow best within an optimum range of temperatures; and the range may be wide for some species, narrow for others. Plants survive only where temperatures allow them to carry on life-sustaining chemical reactions.

Cold

Heirloom garden plants differ in their ability to survive cold temperatures. Some tropical plants are injured by temperatures below 60°F. Arctic species can tolerate temperatures well below zero. The ability of a plant to withstand cold is a function of the degree of dormancy present in the plant, its water status, and general health. Exposure to wind and bright sunlight or rapidly changing temperatures can also compromise a plant's cold tolerance.

Heat

Heat tolerance varies widely from species to species. Many heirloom vegetable garden plants that naturally grow in arid tropical regions are naturally very heat tolerant, while subarctic plants and alpine plants show very little tolerance for heat. High night temperatures are often the most limiting factor for many plants.

Water

Different vegetable garden plants have different water needs. Some tolerate drought during the summer but need winter rains. Others need a consistent supply of moisture to grow well. Careful attention to the need for supplemental water can help you select garden plants that need a minimum of irrigation to perform well in your garden. If you have poorly drained, chronically wet soil, you can select lovely vegetable garden plants that naturally grow in bogs, fens, and other wet places.

pH

The ability of plant roots to take up certain nutrients depends on the pH, which is a measure of the acidity or alkalinity of your soil. Most vegetable garden plants grow best in soils that have a pH near 7.0. Most ericaceous plants such as azaleas and blueberries need acid soils with pH below 6.0 to grow well. Lime can be used to raise pH and materials containing sulfates such as aluminum sulfate and iron sulfate can be used to lower pH. The solubility of many trace elements is controlled by pH, and only the soluble forms of these important micro nutrients can be used by plants. Iron is not very soluble at high pH and iron chlorosis is often present in high-pH soils, even if they contain abundant iron.