Deep Roots Hydroponics - Frequently Asked Questions

A: Flourescent lights tend to produce thinner, lighter flowers and fruits, and tend to cause plant nodes to grow closer together, making for denser foliage. They are best used to maintain a plant, provide light for cuttings or clones, or for early vegetative growth.

HID lights come in two varieties, metal-halide (MH) and high-pressure sodium (HPS). MH bulbs tend to produce a whiter light that is better for vegetative growth. HPS bulbs tend to produce a more full-spectrum light that is more yellow in color. Both can be used for either the vegetative or flowering phases of growth, but experience growers tend to have a favorite. MH grow lights tend to be used earlier and for vegetative, and HPS grow lights tend to be used more often for flowering.

LED lights are relatively new on the scene. The general concensus seems to be that the newest, most advanced models are about 75-80 percent as effective as an HPS or MH grow light, and the results seem to vary wildly between models. It is widely accepted that they do take up much less power (about 30% as much per sq. ft. as an HID light) and produce far less heat, which are two major advantages. Of course the other important factor is cost; LED lights tend to cost about 3x as much as a comparable MH or HPS light.

In summary, consider flourescent grow lights for your table-top herb garden, cuttings and clones, and to maintain early vegetative growth of starts before transplanting. For more powerful vegetative growth, use MH grow lights, and for flowering phases use HPS. Finally, if you have serious power, space, and heat concerns, consider LED.

A: The general rule of thumb for amperage draw for grow lights is approx. 5 amps per 1000 watts. Typically a twin-600 (1200 watts) will also draw around 5 amps. Multiply the amount of lights you are using by 5 in order to determine how many amps you will need, add 10 for a safe margin, and then make sure you have that amount of amps available through your sub panel to help prevent equipment damage, light schedule problems, and fires.

A: A ballast is a reservoir for electricity; it is designed to accumulate and store power, then feed it at a steady, reliable rate to your grow light bulbs (or lamps). Grow light bulbs are expensive and potentially sensitive to irregularities in power, and require a strong, steady flow of power in order to ignite and stay properly lit. Modern ballasts also act as a circuit breaker, providing a crucial point of safety between your grow lights and your power panel. Magnetic ballasts tend to produce an audible "hum" (which some have said is too loud over the years) and tend to run rather warm, so the heat they produce is a consideration if they are installed inside your grow space.

There are two types of ballasts, digital and magnetic (or analog). A magnetic ballast functions purely based on the laws of electromagnetism. It has a large charged core that draws power from the circuit when turned on. It stores an ample supply of power that the bulb then draws from, without any smart circuitry or "brain" managing it.  A digital ballast, by contrast, contains modern smart circuitry that allows the ballast to be dimmed, run a variety of bulb wattages, and auto-sense a 120 or 240 volt power source.  Digital ballasts tend to run a little cooler than analog ballasts, and often are completely silent in their operation.

Some growers insist that a brand new magnetic ballast is still the best way to get the most intense, full-spectrum, brightest light for your dollar. Others insist that the modern digital ballasts offer too many advantages and too big of yields not to use them. It's best to consider your budget, your environment, and your goals before making a choice.

A: A grow light has three essential components: 1) the ballast, which conditions, steadies, and supplies the power to the bulb, 2) the hood, which provides a housing to mount the bulb in, and the necessary reflectivity to focus the light on the plants, and 3) the grow bulb itself, which is what converts the power from the ballast into light and makes your plants grow.

The hood is an essential component because without it, you'd have light sockets dangling from the ceiling with really hot bulbs exposed on all sides. In order to properly mount the light, you need a fixture, and in order to focus all the growing light from the bulb, and reflect it back down toward your plants instead of just lighting up your ceiling.

Hoods also provide a container for the heat that the light creates. If you use a sealed hood with glass lens, although you experience a slight drop in lumens, you create a closed area that can be ventilated, thereby evacuating the hot air that the bulb is creating and replacing it with cooler outside air. This popular technique for minizing grow light heat is not possible without a solid hood.

Modern hoods also have a variety of sizes, flange and edge designs, and ventilation ports that allow for a wide variety of choices in mounting, cooling, and reflecting your grow light.

A: In essence, they aren't really. The still do the same essential function that a light bulb does; they take in electricty, pass it through some medium that will glow when charged (the filament), and then send it on through the circuit. The difference is that grow light bulbs, instead of using a thin wire for a filament, grow light bulbs use a variety of other materials to produce the arc of electricity that creates light.

Metal halide bulbs use metal salts and argon gas to create a bright arc that is whiter, or bluer, in color.

Click here for a great explanation of how Metal Halide bulbs work.

High pressure sodium (or HPS) bulbs use sodium salts 

Click here for a great explanation of how HPS works.

Different bulbs use different grades of material and various substitute materials (usually rare-earth metals and minerals) that create differences in light temperature (or color) and intensity. Nicer bulbs that use nicer materials claim to work better, and they cost a little more. We find that a good GE or Electrolux bulb works fine.