by Nebula Haze
HLG 300 R-Spec is out of stock. Recommended LED upgrade: Mars Hydro SP3000 (2024 Version)
Lately, the HLG 300 R-Spec LED grow light I reviewed on this page seems to be out of stock. It may be discontinued, at least for now. But as a cannabis grower since 2008, I’ve learned this is the way of the LED grow light world. The best LED grow lights often come and go, but overall the technology continues to improve at a steady rate. And that’s the case again. Although I loved the HLG 300 R-Spec, the newer Mars Hydro SP3000 appears to perform just as well or even better as far as cannabis growth and yields, uses about the same electricity, and can be used in the same way. If you were considering an HLG 300 R-Spec, consider that as an alternative.
Here is our complete Mars Hydro SP3000 cannabis grow setup tutorial.
The Mars Hydro SP3000 is my recommended upgrade LED grow light for growing cannabis, now that the HLG 300 R-Spec isn’t available.
Here is my original review in case they start releasing more HLG 300 R-Specs.
Review of the HLG 300 R-Spec LED for Growing Cannabis
I’ve now grown multiple sets of cannabis plants with the HLG 300 R-Spec LED grow light so it’s time to do a review! I have been beyond impressed by the cannabis bud quality produced by the HLG 300 R-Spec LED grow light. However, it is not a perfect LED grow light for growing cannabis. It has amazing pros but also some cons. Let me spell them out for you here, to help you decide whether this is the best LED grow light for your marijuana grow.
About the HLG 300 R-Spec LED grow light
Is the HLG 300 R-Spec LED grow light good for growing cannabis?
HLG, short for Horticulture Lighting Group, has been releasing cannabis LED grow lights (also called “quantum boards”) for many years. These LED grow lights were designed with cannabis plants in mind from the beginning. In fact, HLG first got the idea for its quantum boards after seeing home marijuana growers assemble similar style LEDs at home.
This is the HLG 300 R-Spec (long version). Cannabis plants seem to respond well to LEDs that have lots of little diodes spread apart on a relatively large board.
Now let’s get into the details of my experiences growing marijuana under this LED grow light
Pros of HLG 300 R-Spec
- High THC levels – in side-by-side grow experiments with clones, the R-spec typically produces higher THC levels other grow lights
- High-quality buds – sparkly, beautiful, and dense
- Brings out purple – tends to turn buds and leaves purple, especially the parts of the plant closest to the light (some strains stay green no matter what)
- Fast plant growth – Plants grow fast and healthy with relatively few nutrient deficiencies or light stress compared to some other LEDs.
Cons of HLG 300 R-spec
- Tall stretchy plants – Due to the high amounts of red in the spectrum, plants tend to get tall and grow “stretchy” with a lot of space between nodes. However, this can be controlled and even used to your advantage with plant training.
- Medium yields – Although I wouldn’t say this light gets low yields (it has produced over 10 oz with a 270W light, which is over 1 gram/watt), it can’t compete on yields with “high-yield” LED grow lights like the HLG 350R LED grow light, which seems to get the best yields per watt of any LED grow light I’ve grown with so far.
Conclusion: I think of this as my “bud quality” light. These are the buds I bring out for guests.
This grow light may be the best LED grow light for you if you’re seeking the best bud quality. However, if you want plants that stay short, and/or seek to produce the best yields per watt with an LED, you probably would be happier with the HLG 350R which is designed for the same size space, makes somewhat shorter bushier plants, uses comparable electricity, produces excellent bud quality, and tends to get better yields.
Ready to see what the HLG 300 R-Spec LED grow light can do with marijuana plants?
Examples of plants I’ve grown under the HLG 300 R-Spec LED grow light
I grew these cannabis plants under the square version of the HLG 300 R-Spec LED grow light.
In natural light
These plants were all grown under the “long” version, the HLG 300L R-Spec, a newer model which has been designed for 2’x4′ spaces (a common size for a grow tent or closet).
Whenever I’ve grown with the HLG 300 R-spec LED grow lights, I’ve been impressed by the bud quality. This LED grow light produces smooth cannabis buds that look great and produce max amounts of THC for the strain.
Examples of cannabis buds grown under the HLG 300 R-spec LED grow light
Here are closeups of cannabis buds while they’re growing under the HLG 300 R-Spec.
Example of cannabis buds I grew under the HLG 300 R-Spec light after they’ve been dried and cured:
I hope that review helped you decide if the HLG-300 R-Spec is the best LED grow light for you!
Want to know how to set up a grow space with the HLG-300 R-Spec. Here’s is a breakdown of this entire grow setup with a shopping list and links so you can copy my results exactly.
Copy these results at home:
- Complete supplies list with links
- Instructions on how to set up
- Resources to start growing.
Learn how to get set up and grow weed with the HLG 300 R-Spec.
