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The Problem with Bar LED Grow Lights – 4 Ways to Fix It

Bar LED Grow Lights – 4 Must Dos

Alex Grady
Bar LED grow lights are extremely popular. It’s no wonder – all plants are directly under a light source. This means:
  • There are no hot or cold spots - light distribution is incredibly uniform

  • You get an even canopy, with no taller central plants casting shadows

  • All light is beamed down, rather than out - you lose less light to walls

Something to bear in mind, is that BAR LED grow lights are so large, that they take up the entire footprint of your grow tent. Once you position them beneath your fan and filter, your light bars are 30cm closer to your plants.

With the amount of light modern LED bars emit (up to 3.0μmol/ W!), you need to take these steps to ensure plants can cope with all this light.

Here are 4 simple steps you can take to maximise your bar LED grow lights.

4 Must Dos with BAR LED Grow Lights

There are 4 main ways to help plants flourish under such a high light intensity:

1. Dim Your Bar LED Grow Lights

Bar LED dimming dial icon

If you have less headroom the easiest thing to do is to simply dim your bar LED grow lights down.

Doing this reduces LED grow light levels slightly, without altering your grow light spectrum. For young plants, it's essential that you dim your LED lights anyway.

You still get the very high efficacy of your fixture - so you still get a super high output for your running costs. BUT you're just not getting the most out of your cutting-edge LED grow lights. It's like buying a race car and then driving it at 30mph.

Many of the best LED grow lights have a dimming function via either a dimming dial on the grow light itself or via an external lighting controller.

If you can, connect to a grow light controller with auto dim. It'll dim your LED lights at a set temperature.This way, you can continue running your LED grow light at full power and only dim it if your grow room temperature climbs too high, as a last resort.

You also get access to a range of other cool features, such as.

Sunrise and Sunset mode.
Gradually increase and reduce your grow room temperature over a longer period, to mimic the patterns of natural light.

Manage multiple LED Grow Lights
To make management easier, you can control multiple fixtures from one point.

2. Upgrade Your Tent To A Taller Model

Tall Tent Icon

To avoid dimming your LED light bars, you can easily regain height by upgrading your tent to one that's at least 2.2m tall.

There are a number of high-ceiling tents available, such as the BudBox Pro HL Grow Tents. You get 20cm more headroom than you'd get with a standard 2m tall model.

That extra space means you can fit your extraction system above your LED grow light, while still maintaining a safe distance between your grow light and canopy.

3. Take Your Fan And Filter Out Of The Way

Inline CarboAir Extraction Kit

The new CarboAir Inline Carbon Filters mean that you don't actually have to have your fan and filter inside your tent anymore.

These carbon filters have a spigot on either end. This means that you can connect your extractor fan to one end. You'd attach ducting to the other end and feed it into your grow tent via a port.

You get the same amount of extraction and odour filtration, but the clever inline design lets you get back that crucial space at the top of your tent.

4. Add CO2

If your bar LED grow light is too close to your canopy, you risk plants getting more light than they can photosynthesize. You can offset this by adding CO2.

Remember, for photosynthesis (sugar production) to occur, you need light, CO2 +and water.

Photosynthesis: light + water + CO2 > sugar + oxygen

If plants get too much light but not enough CO2, they can become stressed and pohotosynthesis won't be occurring at its optimum rate.

It has been found that plants can use up to 1200 ppm in flowering, In a typical home, where there are people exhaling CO2, levels can reach up to 800ppm. That's not even close to what plants can use.

To ramp up photosynthesis and relieve stress, add the CO2 needed.

As well as preventing problems, adding CO2 with bar LED grow lights can increase yields by 20 – 30%. During flowering, you can slash the time it would normally take to produce flowering.

We recommend supplementing with CO2 anyway, but with the kind of light you get from top bar LED lights (up to 3.0 μmol/w), it's crucial.

It's most important to add CO2 during the first 2 - 3 weeks of bloom, when flower production begins.

How To

Dimming Your Bar LED Grow Lights

bar LED grow light Maxibright bar LED grow light

Top-end LED grow lights tend to have an in-built dimming dial. The ones that don't can normally be connected to a 0 - 10V controller, like the Omega Matrix Lighting Controller.

For instance:

Omega 3.0 Infinity Pro LED Grow Lights can be dimmed in 25% increments (25%, 50%, 75% & 100%)

For best results:

Connect to a grow light controller. One that'll auto dim lights at a set temperature, like the Omega Matrix Lighting Controller, Gavita Master Controller EL1 & EL2, Gavita Master Controller EL1F & EL2F or Lumatek Digital Panel PLUS 2.0 Controller.

This will enable you to run your grow lights at full power, unless dimming is unavoidable.

Depending on which LED grow light you buy, you will have a couple of options.

As with most advanced HPS lights, LED grow light dimming is carried out through a 0-10v signal. So most LED grow lights will have an RJ45 input that you can use to connect to a 0 - 10V grow light controller, like the Omega Matrix Lighting Controller.

Note: Gavita Controllers work a little bit differently

Gavita LED grow lights won't work with other brand controllers due to the connection type. To dim them down you have two options:

Gavita grow Tent Set-Up

  1. Connect it to a Gavita Master Controller using a special adapter (1 per LED) With the EL2 model, you can also control up to 2 other items (e.g. heaters, CO2 equipment). Get an ELF model and you can control fans too.

  2. Use a Gavita RS1 Remote Switch using a special adapter (1 per LED) Manually dim or boost lights from 60 – 115% using a Gavita RS1 Remote Switch

Raise The Roof – BudBox High Ceiling Tents

BudBox Tent

BudBox Pro Grow Tents are a massive favourite at GroWell. We've sold BudBox for over 15 years, and their quality and attention to detail still makes them the best tents money can buy. BudBox Pro HL Grow Tents are 220cm tall. So you get a precious extra 20cm of headroom to play with - perfect for bar LEDs.

Virtually every bar LED grow light on the market covers a 1.2m x 1.2m (up to 1.5m x 1.5m) area - look for tents with these dimensions or tents that can be split into these sections.

For instance, a 2.4m x 2.4m grow tent gives you the same space as 4 x 1.2m x 1.2m tents, so you'd need 4 bar LED grow lights.

Get Inline – Reclaim Your Space

CarboAir Inline Carbon Filters are a must for the bar LED growers.

They keep your carbon filter fully enclosed in an airtight housing. This means that you can actually take the filter out of the tent. You gain back up to 30cm of headroom and you can mount your bar LED lights right at the top of your tent.

CarboAir Inline Carbon Filters match the airflow of RVK fans perfectly, so its an easy upgrade if you already have extraction.

Alternatively, we've put together some great kits including these filters to take all of the hassle out of buying.

    Add CO2 - Offset The Extra Light

    In small rooms, CO2 Bags and TNB The Enhancer CO2 Dispersal Canisters do the trick. They slowly release CO2 over a set period of time. All you do is activate them and hang them. It doesn't get quicker and easier than this.

    To cover a larger area, or for tighter control of your CO2 levels, you're best off using propane gas or bottled gas. Your room is dosed with CO2 when it's needed, to keep levels at the optimum 1200ppm.

      LEDs produce heat that rises up (convection) rather than down over plants (radiant). So during the colder months, you need to add more heat than you would with an HPS. The Grow Gadgets Greenhouse Heater is great.

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