How to set up the HPS or LED grow light in the cannabis grow room

Are HPS Grow lights or Led grow lights?

LED grow lights

While LED lights are not “new” technology (they have been around for the last half century), however up until last year, they lacked critical ability to produce certain kinds of light necessary for indoor growth. These days, cannabis cultivators can purchase LED light setups that allow them to eliminate the need to change bulbs and purchase expensive fans for ventilation.

LED lights also use between 60-90% less energy than traditional HPS or CFL bulbs. That said, if you buy low quality LED lighting, you are wasting both your time and your money. You need to invest in lights that are capable of producing a light spectrum that can fully penetrate your canopy.

LED lights however are increasingly seen as being able to increase the potency of the crop because they seem to help plants produce more trichromes.

Many growers are now experimenting with a mixture of both HPS and LED lighting – which seems to create the best of both worlds – high yields plus high potency. This may be because the combination of the two different types of lighting most closely mimics the natural sunlight that cannabis plants are exposed to when grown outdoors.

LED lights last longer than other kinds of growing lights. They have a lifespan of up to 100,000 hours. Compared to HPS lights, which begin to lose their effectiveness after 2-3,000 hours of grow time and are only expected to last about 10,000 hours, LEDs last about 10 times as long.

LED light costs are also rapidly decreasing and are expected to halve again within the next four years.

While there is still a great deal of debate about whether LED lighting produces lighter yields than other more conventional types of growing, LED advocates claim that in fact their use can yield greater results – but it depends on the quality of the LED lighting that you purchase and set up – and how effective the lighting structure you construct is at bathing your plants in the right type of light for the specific stages of the growing phase.

Temperature & Humidity

These two factors are closely related and have a dramatic affect on how a plant transpires. Typical HID growers will have room temperatures of about 75 degrees F and relative humidity from 65-80%. The reason this works for HID growers is because the massive heat output from the lights creates a micoenvironment at the plant level that matches proper transpiration conditions.

But this will not work with LED! The reason is thatLED Grow Lights do not put out the incredible heat that HID lighting does. So, we must compensate for this and give the plants exactly what they need.

When growing cannabis under LED, temperature must be between 80- 85 degrees F and humidity at 40-45%.

These are the ideal conditions for cannabis transpiration that will have a dramatic effect on plant growth and bud development.

Soil & Hydroponics

The choice to go with soil or hydroponics is a personal decision, however, here are some recommendations to be sure you get the best results under LEDs.

If growing in soil, you must be sure the mixture is well-aerated. A vast majority of nutrient issues and poor yields can be traced back to soil problems right from the start. If your soil mixture is not capable of proper draining, your roots become water-logged and root rot is sure to follow.

This is most prevalent in organic mixtures – they compact too much and, because LEDs do not dry out the soil as HID lights do, it is easy to over water your plants.

A peat-based grow medium is recommended. Products such as Fafard, Sunshine Mix #4, and Pro-Mix are a great place to start. To this, it is recommended to add 40-50% perlite to the medium. This ensures proper drainage and allows plenty of oxygen to the root system. If you choose to use an organic soil, up the perlite to 50% and you shouldn’t have any problems. You will know that it is time to water your plants when the first 2-3 inches of the soil is dry or the plant looks “thirsty” with slightly droopy leaves. Give a thorough soaking and allow the water to run out of the bottom of the pots to ensure aggressive root growth all the way to the bottom.

If you plan to grow your plants hydroponically, there is one crucial step to take to ensure success with eco farm LED Grow lights. As I’ve stated earlier, room temperature of 80-85 degrees F is ideal for plant transpiration. However, hydroponic reservoir temperatures must be kept below 70 degrees F.

Even if using an aerator in your reservoir, water is not able to hold onto enough oxygen if its temperature is over 70 degrees. The result is that your roots will suffer as will your yield! So you have two options – either keep the reservoir outside of the grow space in cooler temperatures or you need to use a water chiller. Ideal temperatures for water are 65-68 degrees F.

Air Exchange

Many would-be growers out there come to me saying how they have everything planned out for their UBER-GARDEN so they can grow 20lbs of dank in just 30 days…or something along those lines.

One of the biggest mistakes I see growers make is having a completely sealed grow space.

An enclosed room – one that gets no air exchange – can grow plants but you will be sacrificing yield in the process! To ensure the best yields, it is imperative that the air is exchanged 2-4 times per hour. Even if supplementing with CO2, your plants CRAVE fresh air and if you allow the air to become stagnant, your plants (and yield) will suffer.

This is one of the biggest mistakes I see, even if they are using LED grow lights because “they are safe now”, being within temperature requirements. But this is not the case!

Pick up an exhaust fan that is capable of providing enough fresh air for your plants. Feel free to ask the folks at eco farm LED about how to to properly size your fan for whatever grow space you have. Also – don’t forget to have a circulation fan inside the grow space to keep the air flowing through the canopy and stems. Not only does this strengthen your plants (they will need it for the massive buds you will produce) but it will ward off mold and fungal growth.

Light Height

In general, stick to the recommendations for light height as shown on eco farm LED‘s website. Proper light height depends a bit on the wattage of light you are using but is critical during vegetative and flowering stages.

Too much light intensity on a seedling can  verwhelm the plant and kill it while too little light during flowering can result in light, airy buds. Vegetative stage plants need the light at 14-18 inches above the canopy while flowering plants need the light lowered to 10-14 inches.

The key to flowering with LEDs is timing. When you switch from a vegetative light cycle of 18 hours on and 6 hours off to the flowering cycle of 12 on and 12 off, you need to WAIT before you lower the light. Wait for a couple of days until you see genuine bud formation before you drop the light. Lowering the light too soon can stunt bud development and negatively affect yield. Once you see flowers, it is safe to drop the light to 10-14 inches.

HPS Grow lights

High-Pressure Sodium lights are one of the most common and turned to grow lights on the market. Key to the popularity of HPS grow lights, is their raw light output. Because of the unique light demands of the cannabis plant, the ability of these lights to produce a large amount of light is incredibly desirable. However, HPS grow lights also produce a significant amount of heat and the light they produce often requires enhancement by Metal Halide lighting for vegetative growth. This also means that many growers opting for HID lighting require separate veg and flowering lights or at least multiple bulbs, adding to the overall expenses of maintaining an HID setup.

• HPS bulbs provide an incredible amount of intense, raw light which lends itself to producing great yields.
• Because they're older, HPS lights are more standardized among different manufacturers, making it a bit easier for growers to compare bulbs and set-ups.
• HPS grow lights have a lower start-up cost than LEDs. It is worth noting, however, that the price gap between comparable HPS and LED grow has become exponentially smaller each year

While the upfront cost for LED lighting is still higher than HPS grow lights, LED grow lights cost less to operate over time thanks to reduced power consumption and the elimination of traditional maintenance. Though less costly, HPS grow lights significantly lose brilliance over time, in addition to requiring more power and maintenance. Alternately, LED grow lights don't lose intensity over time and retain their brilliance until the end of their 50,000-100,000 hour lifespan. Nevertheless, LEDs still can't quite compete with the sheer power of HPS lights.

Bulb Orientation

Some bulbs are horizontal, others vertical, and then there’s universal bulbs. Vertical bulbs can only be used with fixtures in the vertical position. Horizontal bulbs can only be used with fixtures in the horizontal position. Universal bulbs can be used in a horizontal or vertical position. If you aren’t sure what to buy, go ahead and get a universal bulb. It will work in either type of fixture, hence the name “universal”.

HPS (High Pressure Sodium) lamps can burn in any orientation.

MH (Metal Halide) lamps come in three basic types:

• Base Up (BU): Must be operated in the base up position.
• Horizontal ( HOR): Must be operated in the horizontal position.
• Universal (U): May be operated in any position.

Orienting metal halide lamps in burning positions other than those specified can result in severe reductions in performance and potential nonpassive failure.

Lamp life, light output and color can be affected by the burning position. Some burning positions may need enclosed fixtures for safety reasons.

Hanging Your Lamp/Reflector Step-By-Step

Hanging your lamp is easy!

Step 1) First you need to find a stud in the ceiling. When you have located a stud, figure out which direction they run.

Step 2) Next (optional), take a 2×4 and screw it into the ceiling using a drill with screwdriver attachment and 3.5 inch steel screws.

Step 3) After hanging your 2×4, screw “hooks and eyes” in the proper locations along the stud or the 2×4 to correspond with your reflector brackets.

Step 4) Next, if necessary hang your chains to lower and raise the light, otherwise, just hang it and you’re ready to go!

Light Placement

In order to reap a heavy potent harvest, keep your plant growth within the penetration area of your lamp. It’s very important for indoor plant growers to get their light source as close as possible to their plants. The amount of light your plant receives is directly related to it’s yield/flower density. As the light rays get farther from the bulb they begin to disperse and become less intense.

Note: This is the primary reason growers will keep plants small so that way the entire plant is closer to the lights.

Remember not to burn them!!!! Growing Marijuana is more of an art than an exact science. You will need to rely on the experience your little buds are having rather than follow set “plant height” recommendations. Use those as general guidelines, but ultimately your plants are going to determine how close you can get your light to them.

The following chart shows the optimal penetration range for most HID lamps:

Marijuana Lighting for a Closet Grow

When growing weed in a tight space like a closet, you want short, bushy growth.

This ensures maximum yields without needing a large number of plants. High quality buds are especially important, since the small space limits potential yield size.

Heat can become problematic in a small grow space, so a high-output LED grow light is your best bet.

Go with a full-spectrum LED panel with an actual wattage of 300 to 600 watts

It won't be cheap, but you'll save money in the long run and avoid a lot of headaches with heat.

Supplement the LED with blue-spectrum fluorescent bulbs, or equivalent LED bars, hung vertically next to the plant(s). Go with a color temperature of 5500K to 6500K and around 45 watts per bulb.

Fluorescent bulbs will produce some heat, but using an LED for the main light source keeps it manageable. We recommend LED bars instead of fluorescent, to avoid the heat issue altogether and eliminate the need to change bulbs.

Specific Example:

For a 3 by 3 foot grow space, you could use a 600 watt LED fixture above the plants and 4 LED bars, or 4 fluorescent bulbs of 45-60 watts each, hung around the sides.

This 2 foot, 24 watt veg/clone bar is ideal. It costs more than a fluorescent bulb, but ends up saving you a lot in the long run, due to lower power usage and no bulb changes. 

If you prefer fluorescent bulbs, you can get them at any department or hardware store or online

You could even switch the colder (5500K to 6500K) bulbs for warmer ones (around 2700K) for the last two weeks of flowering to really ramp up production. The best LED bar for that is this 24 watt bloom bar.

You're going to want to keep the grow contained inside the closet, so a grow tent might be a good idea.

To keep costs down, but still ensure quality, go with the entry-level eco farm 3x3 grow tent).