There are 3 types of bulbs that work well as grow lights: metal halide, high pressure sodium (HPS), and fluorescent. Each type of light fixture has its own advantages and drawbacks. 1  Metal halide bulbs are compact and efficient, producing a very intense light from a small bulb.
The normalized difference vegetation index (NDVI) is a simple graphical indicator that can be used to analyze remote sensing measurements, typically but not necessarily from a space platform, and assess whether the target being observed contains live green vegetation or not.Contents.he normalized difference vegetation index (NDVI) is a simple graphical indicator that can be used to analyze remote sensing measurements, typically but not necessarily from a space platform, and assess whether the target being observed contains live green vegetation or not. Contents.
Nearly all satellite Vegetation Indices employ this difference formula to quantify the density of plant growth on the Earth  near-infrared radiation minus visible radiation divided by near-infrared radiation plus visible radiation. The result of this formula is called the Normalized Difference Vegetation Index (NDVI).To determine the density of green on a patch of land, researchers must observe the distinct colors (wavelengths) of visible and near-infrared sunlight reflected by the plants. As can be seen through a prism, many different wavelengths make up the spectrum of sunlight.early all satellite Vegetation Indices employ this difference formula to quantify the density of plant growth on the Earth  near-infrared radiation minus visible radiation divided by near-infrared radiation plus visible radiation. The result of this formula is called the Normalized Difference Vegetation Index (NDVI).