How many plants can you put under a 1000 Watt HPS?

What’s a HPS Grow Light?

HPS (High Pressure Sodium) grow light is high-intensity luminosity that is emitted when electrical current passes through a narrow arc tube consisting of Xenon and a mixture of mercury and sodium vapor.

HPS technology plays a vital role in cultivating indoor crops today. It involves HPS grow light that come in different shapes and sizes. They commonly get turned on via a pulse start. Note that the light spectrum of the HPS bulbs varies widely between different manufacturers and different lamps alike.
HPS Spectrum Output
By responding to the particular light spectrum, the plants grow and flourish. This physiological process is called photomorphogenesis. The yield you get at the end of the production cycle largely depends on the spectrum output.

With regard to the HPS bulbs, they give off a golden yellow light which maximizes flower and budding production. Those bulbs produce “usable” light that the marijuana plants can utilize. It is referred to as PAR (Photosynthetically Active Radiation) spectrum. That light can be anywhere from 400 to 700 nanometers.
1000 Watt HPS Grow light

At 1000 watts, these bulbs are more efficient than 400 watt bulbs, but less efficient than 600 watt bulbs. This efficiency decrease is significant enough that some growers even recommend to try using two 600 watt lamps for your growing space before making the jump to the 1000 watt lamp.

With this said, we do have to recognize that at 1000 watt, there is no bigger and more productive single HPS lamp solution. And as its light output grows, so does the heat it produces.

Plant Distance: At least 24’’ or 60 cm away from your canopy
Recommended Area: Up to 6’ x 6’ or 1.8m x 1.8m​

How many plants can you put under a 1000 Watt HPS?

The size of grow light you get will dictate how many plants you can grow underneath it. Of course, this can vary quite widely if you decide to employ different training techniques. For example, you will obviously be able to fit in more individual plants using a SOG set-up than you will with a SCROG system.The table below gives you a rough guide, growing small to medium sized plants, of how many plants you can grow under each sized grow light. Remember, this will also vary massively with different strains.

HPS and/or MH Light Bulbs

Some growers add the metal-halide lamps, which have a green-blue spectrum, apart from HPS bulbs to get the well-balanced spectrum output and achieve the best results. That bluish bright light simulates the real spring sun and thus promotes the bushy short growth of the plants.

While metal halides are ideal for the veg phase of growth, the high-pressure sodium light bulbs are more suited for the flowering phase when plants start to produce buds.

Metal-halide lights aren’t as strong as high pressure sodium lights, as they provide up to 115 LPW. Nevertheless, they are more powerful in the blue spectrum range, which actually promotes growth in plants. That’s why metal halides are helpful for vegetative stage.

It is a truth that you can use either HPS or MH lights during the whole production process and obtain good results. However, if you want to get the most out of your crops, we recommend interchanging these two types of bulbs. That will make a huge difference to the spectrum output and your plants as well.

HPS/MH bulbs emit the type of light that is beneficial for plants that have high light requirements such as cannabis. The mix of both HPS and MH lights appears to mimic the sunlight almost authentically, making the buds feature more complex terpene (smell and taste) profile.