The Samsung LM301B and the newer LM301H are mid-power white LED packages that many grow light makers use because they combine high efficiency with a broad, natural-looking spectrum. The chip is only part of the story: a good fixture also needs a quality driver, good cooling and honest specifications.
What are the Samsung LM301B and LM301H?
Samsung makes a family of mid-power LED packages, called the 3030 series because of their 3.0 by 3.0 millimeter size. Two members of the family are widely used in horticulture lighting:
- LM301B, the original, rated by Samsung at 220 lumens per watt (at 0.2 watts and 5000 K).
- LM301H, a horticulture version, and its improved LM301H EVO, which Samsung rates at 3.14 µmol/J at 65 mA and 25°C. The standard LM301H is listed at 3.10 µmol/J.
Samsung quotes lumens per watt for the LM301B and micromoles per joule for the LM301H, which is why grow light pages mix the two units. Lumens measure brightness to the human eye; micromoles per joule measure plant-usable photons, which is what grows plants.
Why growers like these diodes
- Efficiency. At chip level these packages sit near the top of what white LEDs achieve, so a well-built fixture can deliver a lot of plant light for each watt.
- Broad white spectrum. White diodes provide blue, green and red together, giving a full spectrum with a more natural color to the human eye than the blue of MH lights or the yellow and red of HPS lights.
- Many small diodes. A fixture built from many mid-power diodes spreads its light and its heat across a large board, which helps with even coverage and cooling.
- A track record. The name is well known among growers, so it is easier to compare fixtures.
Chip efficiency is not fixture efficiency
Samsung's figures describe a single diode under lab conditions, at a set current and a temperature of 25°C. A finished grow light runs hotter, pushes the diodes harder and loses a little power in the driver, so the fixture always delivers less than the chip figure. As an example, one maker of lights using LM301H EVO diodes lists the diodes at 3.14 µmol/J and the whole fixture at 2.85 µmol/J. That is still excellent, but it is the fixture number, not the chip number, that you pay electricity for.
When you compare lights, compare fixture efficacy in µmol/J, ideally from an independent test. Our guide to LED vs HID grow lights gives the numbers for the older lamp types.
What else decides how good a fixture is
The driver
The driver converts mains power to the current the diodes need. A poor driver wastes energy, runs hot, flickers or fails early. Ask which driver is used and what its warranty is.
Cooling and layout
Diodes lose efficiency and lifespan when they run hot. A large heat sink and spacing that lets the board shed heat keep output steady over the years.
Optics and coverage
Two lights with the same chips and the same wattage can light a space very differently, depending on how the diodes are laid out. A published PPFD map shows how evenly a fixture covers a given area at a given height. See how many LED grow lights you need.
Protection and safety
If water might reach the light, look for an IP65 or IP67 rating. Read about IP65 vs IP67 grow lights.
Beware of look-alike chips
The popularity of the name means some lights claim Samsung diodes without using them, or use cheap "Samsung-like" parts. Protect yourself:
- Ask for the exact diode model, for example LM301B or LM301H EVO, not just "Samsung diodes".
- Check the manufacturer's datasheet for the diode.
- Be suspicious when the price is far below that of comparable lights.
- Choose a seller that offers a clear warranty.
LM301B or LM301H: does it matter?
Both are strong choices. The LM301H and the EVO versions are the newer, more efficient horticulture-focused parts, while the LM301B is the proven original. In real use the difference between a well-built LM301B fixture and a well-built LM301H fixture is smaller than the difference between a good fixture and a poor one. Focus on the whole light, not the chip letter.
Mid-power or high-power diodes?
LED grow lights fall into two broad families. The LM301B and LM301H are mid-power diodes, which run at around 0.2 watts each, so a fixture contains hundreds of them. High-power diodes and chip-on-board (COB) modules run at several watts each, so a fixture contains far fewer, packed more tightly.
- Mid-power: the light and heat are spread over a large area, which helps even coverage and cooling. Many models are thin, flat panels or bars.
- High-power or COB: the light is concentrated, which can reach deeper into a tall canopy from a distance but needs stronger cooling and good optics to avoid hot spots.
Neither is simply better. The right choice depends on the space, the crop and how well the fixture is built.
Reading a fixture spec sheet
When a maker publishes real numbers, you can compare lights honestly. Look for:
- PPF (µmol/s): the total plant light the fixture produces. See what PPFD is.
- Efficacy or PPE (µmol/J): PPF divided by input power, for the whole fixture.
- Input power (W) and the voltage range the driver accepts.
- PPFD map at stated heights and areas.
- The diode model and the driver brand.
- Dimming method: a built-in knob or a dimming port.
- IP rating for the fixture. Read IP65 vs IP67 grow lights.
- Safety certifications from a recognized testing laboratory, such as UL or ETL.
- Independent listings such as the DesignLights Consortium horticultural lighting list, which publishes tested efficacy.
- Warranty length and what it covers.
How long do LED diodes last?
LED life is usually quoted as the hours until light output has fallen to a set percentage of its starting value, often written L90 or L70. The figure depends heavily on temperature and current: diodes that run cool and are not pushed hard last far longer. Read the maker's stated figure and the conditions it applies to, and remember that the driver is often the part that fails first. A fixture with a solid warranty shows the maker stands behind both.
Key takeaways
- The LM301B and LM301H are mid-power white LED packages, rated by Samsung at 220 lm/W (LM301B) and up to 3.14 µmol/J (LM301H EVO).
- Chip efficiency is higher than fixture efficiency, so compare fixture µmol/J.
- The driver, cooling, optics, IP rating and warranty matter as much as the diode.
- Ask for the exact diode model and the datasheet, and be wary of look-alike chips and very low prices.
- A well-built LM301B fixture and a well-built LM301H fixture are both strong choices.
Questions about Samsung diodes
Is Samsung the only good diode maker?
No. Other reputable makers also produce horticulture LEDs. A named, genuine diode with a datasheet is the point, not the brand alone.
Do better diodes grow better plants?
Better diodes make more plant light from each watt and last longer. Plants respond to the light they receive, so an efficient fixture mainly gives you the same light for less power.
Does the diode decide the spectrum?
In part. White diodes such as the LM301B have a broad spectrum, and makers can add red or far-red diodes to shape it further.
My LED grow lights and Samsung LM301b/h
My LED Grow Lights use Samsung LM301b/h LEDs, which the brand describes as affordable and dependable world-class technology. Combined with full-spectrum white light, IP65 or IP67 ratings, 120v/240v operation with automatic voltage detection, a dimmer switch and a 3-year warranty as standard unless otherwise noted in the product description, that makes them a dependable choice for indoor growers. See all of our LED grow lights, or read about full spectrum LED grow lights.