Grow Light Movers
The best way to simulate the natural movement of the sun is to add a grow light mover to your system. Most plant grow lights lose intensity the farther away you place your plants. The only true ways to ensure uniform light penetration throughout your plant canopy is to either move the plants or move the light. Obviously, moving the plants all over your growing space each day would be cumbersome and could easily damage the plants. Light movers give the indoor gardener an easy and affordable way to spread light around their garden.
Grow light movers can significantly increase your indoor garden's efficiency. In addition to providing more uniform light distribution throughout the growing area, using a light mover also allows you to place the lights closer to your plants without risking burned tips. This is also a good way to avoid the "pyramid effect" of all your plants growing toward the light source. Many of the newer light movers even have a pause setting at the far ends of the rail so the center of the garden does not get twice the light. Because the overall light intensity will be greater, you can also grow more plants in a smaller area by placing them closer together.
Choosing a Grow Light Mover
The size of your growing area determines the best type of light mover for you. Make sure to choose a light rail that will fit comfortably in your garden, with a little bit of extra space at each end. A 6' rail needs more than six feet of space because the light is usually attached to the rail at the midpoint of the light hood. You need to allow for the hood assembly to extend past the end of the rail when it is at full extension. When in doubt, choose the smaller system and expand with extension rails. It is far easier to add to the system if you have extra room than it will be to cram a big system in a small growing space.
The speed and frequency of the light mover's cycle is usually preset, depending on which model you choose. Some of the more advanced systems allow the gardener to adjust the time or travel distance of the light cycle. Check the product specifications carefully before choosing a light mover, especially if your garden has specific light cycle requirements.
Some models use chains and pulleys, which may not be a good choice if noise will be a problem. Other light mover systems are operated by drive motors. These can be quieter, but are usually more expensive and may create maintenance issues if the motors fail.
Linear vs. Circular grow light movers
Linear grow light movers move your light back and forth along a single rail. These obviously work best for gardens that are long and narrow. Multiple linear light movers installed parallel to each other can be very effective for larger grow spaces.
Circular grow light movers allow you to attach multiple lights on the same track, increasing your light coverage even more. Some models have expansion rails available that will allow you to rotate up to five lights at once. With a circular light mover, you can use a mix of metal halide and high pressure sodium grow lights to give your plants the full spectrum of usable light (blue and red). They work very well for larger grow spaces that are the same width and length.