What the Plant Needs

A plant needs five resources and a good environment to grow well. The yield of a plant is dependent upon the use of all the resources available to the plant and the grower keeping the plant's environment as constant as possible.

Increasing only one or two resources has no effect on the plant. A plant will only do as well as the weakest resource available to it, so the balancing of all the resources at the same time is the only way to increase a plant's production. This chapter explains how the resources are related.

These are the building blocks for good plant growth. The grower must continually balance these resources for the plant.

The Plant's Resources

• growing mediums & nutrients
• water
• grow light
• oxygen
• carbon dioxide

The Plant's Environment

• pH
• humidity
• root temperature
• plant temperature

Growing mediums and nutrients are treated together.
Water that is of drinking quality is good for indoor growing.
cause many problems in a closed system.

Artificial light is never as good as Sunlight. Bringing light bulbs closer to
plants can produce greater light intensity than the Sun, but a bulb with
a complete color spectrum is yet to be invented.

Oxygen is usually freely available to plants because the leaves actually make an excess of it during the daylight. However, the roots are always struggling to get sufficient oxygen.

Carbon dioxide is usually in short supply for indoor plants under bright lights.

pH is without a doubt the most important factor in a plant's life. If the pH
is wrong, all the nutrients are wrong.

Humidity is not a critical factor, but very low humidity cuts down CO2 and
light uptake, which slows growth. Very high humidity causes
pathogens to flourish.

Root temperature for most of your favourite plants (except cuttings) is ideal around 75°F (23.9°C). However, in full water systems, try to keep the water below 70°F (21.1°C) to slow down the pathogens. Note that all growth and chemical reactions speed up as the temperature increases.

Plant temperature up to about 85°F (29.4°C) is very comfortable for most of your favourite plants, but these plants can survive up to about 100°F (37.8°C). In supercharged gardens, temperatures over 85°F (29.4°C) will cancel out all the other good work the grower has done for the plants. The higher temperatures affect photosynthesis, CO2 uptake and plant transpiration, and internal temperature. Plant growth then progressively slows down.