Light and Plant Growth
For Indoor Gardens

HPS light for vigorous plant growth

If you want to see lots of healthy plant growth in your garden, light is a very important factor. Without the right lighting, it will not matter how well the temperature is maintained or how well you feed your plants. The tricky part is that light requirements are a little different from plant to plant.

If you want to understand how light affects your plant growth, just keep reading...otherwise use the link below to help select the appropriate lights for your situation.

Grow Light Selector Tool

Furthermore, lighting requirements usually increase as plants go from the seedling or clone stage to the vegetative stage and finally into flowering. Below are the general guidelines for producing the ideal lighting conditions in your garden, followed by links that will further help you make appropriate lighting choices.

The General Guidelines

In general seedlings, clones, and young vegetative plants need about 25 watts/sq.ft. to develop properly.

Vegetative stage plants over 12 inches tall and more mature mother plants need a little more light to stay healthy...about 20 to 40 watts/sq.ft. (and can handle more if plant growth needs to be sped up).

Most plants in the indoor garden will be heavily fruiting or flowering plants, such as food crops or decorative flowers. Plants such as these require considerably more light to produce healthy fruits and flower buds than the amount of light required to grow stems and leaves vegetatively. The ideal range without CO2 supplementation is 50-60 watts/sq.ft.. With the addition of CO2 into the garden and all other plant growth factors perfect, light requirements increase to 60-80 watts/sq.ft..

Flowering and the Light Cycle

Forcing your indoor garden plants to flower and produce fruits is a special situation that is directly related to your light cycle schedule. In order to keep most plants in the flowering stage, you need to give them 12 hours of uninterrupted darkness every night at the same time. Different plants will require this treatment for different lengths of time in order to finish their flowering cycle. For more information, visit my flower forcing page.

The Effects of Lighting on
Other Plant Growth Factors

It is important to understand the relationship of light to the other growth factors. As you increase the light in a garden, you will also be increasing the temperature in the gardening area. Warmer air holds more water vapor and increases plant transpiration rates, and therefor can cause the humidity to rise. If you maximize your lighting and temperatures are running a little bit on the warm side, chances are pretty good your plants are running short on CO2.

In addition, increasing the light will also increase the nutritional requirements of your plants. Sometimes you need to increase your nutrient strength to accommodate the plants. At other times the plants' increased water consumption will be enough to draw in the extra nutrients without increasing the nutrient strength.

To better understand the effects of light on your plants, explore the following...

Leave Plant Growth and Light
Goto the Troubleshooting Home Page

Go to the Grow Light Selector Tool

Other Hydroponic Gardening Tips