How much light?

How much light?
In a 4′ x 4′ closet situation, how many square feet does each plant need? I am considering the Northern Light hybrid. Also, how many square feet does a 400w HPS cover? I would like to have 15-20 plants.

Doobieous Dimensions
Antioch, Tennessee

Since flowering is regulated by the light cycle, marijuana plants of any size can be forced to flower so growers have a choice of number of plants in a given area.

Every garden has a maximum carrying capacity based primarily on its area and the amount of light it receives. The greater the intensity of the light, the denser a canopy it will support. The most efficient use of this light is to cover the space with canopy as soon as possible.

Gardeners give plants anywhere from 1/2 foot (6″ x 6″) to 4 square feet (2′ x 2′). The advantage of the smaller spacing is that each plant has to grow less for the canopy to be filled. This saves a tremendous amount of growth time. The advantage of large plants is that fewer are needed.

A 400 watt HPS lamp covering 16 square feet has an input of 25 watts per square foot. A 1000 watt HPS has an input of 62.5 watts per square foot. Although the 400 watt lamp will support adequate bud growth, a 1000 watt lamp is required in order to produce dense large buds.

Readers with grow questions (or answers) should send them to Ed at: Ask Ed, PMB 147, 530 Divisadero St, San Francisco, CA 94117, USA.
You can also email Ed at [email protected] and send queries via his website at www.ask-ed.net.
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