Many growers choose to use separate grow areas for different stages of growth. That includes using one grow light specifically for starting seeds and vegetative growth phases, which includes mother plants.
Keep reading below to determine which one may best suit your specific needs.
What Are The Best LED Grow Lights For Starting Seeds:
The best grow light for starting seeds is a grow light that only emits blue spectrum, since that’s the only spectrum needed by seedlings during this phase of growth.
This doesn’t mean a full spectrum grow light can’t start seeds. A grow light that emits full spectrum light can start seeds, but only the blue portion of the spectrum will be absorbed by the seedlings.
You want to find a grow light that emits light in the 4000 to 6000 Kelvin range. That range contains the most blue light.
A second important factor when choosing the best LED grow light for starting seeds is the strength of the light. Many people choose to start seeds and vegetative growth with weak blue grow lights.
This can be problematic because even though seeds don’t need strong light, the light intensity from a single bulb can be too weak to start seeds, which can result in stretchy plants.
In my post about Calculating The Grow Light Strength Needed To Grow Cannabis, I talk about the proper amount of light for starting cannabis seedlings, which is around between 200 to 300 PPFD.
Below I list specific LED grow lights that you can purchase that would provide good light strength to your seedlings.
What Are The Best LED Grow Lights For Vegetative Growth:
Similar to starting seeds, the type of grow light you need for vegetative growth or mother plants is a grow light that only emits blue spectrum light. Blue spectrum light is in the 4000 to 6000 Kelvin range of the spectrum.
The difference in this phase of growth is that the light needs to be much stronger than when you’re starting seeds.
The vegetative phase of growth is critically important for your cannabis plant’s future yields. This is the phase where the plant develops its physical structure.
Running a low powered T5 or T8 light during this phase could risk stretchy plants, which is why I recommend against this option. Strong light will keep those nodes tightly spaced during vegetative growth.
Take a look at the lights below that will provide sufficient intensity for maximum growth and development during this phase.
The Best LED Veg Grow Lights:
The HLG 300L B-Spec may look small, perhaps for a 2×4 foot grow area. But the LEDs on the HLG 300L B-Spec are actually strong enough to grow seedlings and mother plants in a 4×4 foot area.
The B-Spec version of the HLG 300L model pictured above has a spectrum and LEDs specially geared towards plant growth in the vegetative phase. In other words this is a full blue/white spectrum grow light for seedlings and mother plants.
Take a look at the HLG 300L B-Spec spectrum below:
This seedling grow light utilizes Samsung’s LM301H 3500K white spectrum, plus 470nm blue LEDs. Out of all the LED grow lights I’ve seen, the HLG 300L B-Spec is the most dedicated seedling and veg spectrum available.
Recommended Distance From Plants:
HLG recommends hanging the 300L between 24 and 32 inches above your plants. If you’re using this grow light to start seeds, you want to hang it on the higher side near 32 inches. If you’re using the 300L in the vegetative growth phase, you should hang it closer to 24 inches.
Keep an eye on your plants initially and adjust the distance if you notice signs of heat stress or stretching.
The HLG 300L B-Spec pulls 270 watts from your outlet when running at full capacity. If you desire, you can dim it down to 90 watts, or 33% power.
Sure there are small grow light bulbs and tubes available for seedlings and veg phase as well (click here if you want to see those), but the light strength & spectrum quality doesn’t compare in a head to head comparison.
In addition, you’ll need several of those units to cover the 4×4 foot space you get from the HLG 300L B-Spec.
This is the HLG 260 watt B-Spec DIY kit. If you have 20 extra minutes to do an easy assembly, you can veg 4×4 feet of space and save $100 over the HLG 300L mentioned above!
Don’t be scared by the word DIY – there’s no soldering required! Only a screwdriver and wire strippers (or scissors). One person described the light as “fun and easy to put together,” in addition to saying they’re very happy with this vegetative phase grow light.
This HLG 260 watt B-Spec grow light is manufactured specifically for vegetative growth, with a 3500 kelvin spectrum plus 470nm blue LED diodes.
You can see in the spectrum image above that there’s little or no red spectrum, so you won’t be able to use this grow light for flowering.
The grow light is dimmable as well. All you need is a screwdriver to adjust the dimmer located under the rubber plug on the driver.
Last, this grow light comes with a one year warranty. As a DIY kit the manufacturer can’t warranty as long as pre-assembled grow lights, but HLG is a quality brand that I haven’t heard of any reliability issues from.
HLG 260 Recommended Distance From Plants:
HLG Recommends you hang this grow light between 24 and 32 inches above your plants. If you’re using this grow light to start seeds, you want to hang it on the higher side near 32 inches. If you’re using the 300L in the vegetative growth phase, you should hang it closer to 24 inches.
Keep an eye on your plants initially and adjust the distance if you notice signs of heat stress or stretching.
Click here to see more details and pricing for the HLG 260w B-Spec Grow Light at LED Grow Lights Depot
The Best Large Grow Light For Vegetative Growth
If you need to light a large grow space for vegetative growth, consider the Scynce LED Raging Kale 2. This grow light has the same blue spectrum, but covers 6×5 feet for seedling growth, or 3×4 feet for vegetative growth.
Scynce LED is known for making powerful LED grow lights with the best technology. Their full spectrum model called the Raging Kush is featured in my post about the Best LED Grow Lights for Growing Cannabis in 2023.
The Best Cheap Grow Light For Starting Seeds or Vegetative Growth: Metal Halide
This 400 watt iPower metal halide grow light kit will give you the power and the blue vegetative spectrum you need at an affordable price. It even includes a separate HPS bulb to use during flowering if you want.
The wing reflector will ensure the light is spread evenly across your grow space. You can light a 3×3 foot to 4×4 foot area for vegetative growth with one of these affordable grow light kits.
From looking at the spectrum chart you can see it has a high amount of blue, yellow, green, orange, and not much red. This light spectrum was specifically designed for vegetative growth.
As with any grow light, you will need ventilation in your grow space to keep the area cool while using this grow light.
|iPower 400w MH/HPS grow light:|
|Ballast:||400 watt, dimmable!|
|Dimensions:||21″ x 17″ x 6″|
|Coverage:||3×3 to 4×4 feet veg coverage|
|Where to buy:|
Why I advise against tube grow lights (T5/T8) for seedlings and mother plants:
When comparing to LEDs, the spectrum is not as complete, and the light intensity is sub-par. When you read about light intensity required during the seedling and vegetative phase of growth, and then look at how strong the tube grow lights are, they seem a bit weak and probably don’t give the best possible results.
What is the vegetative phase (veg)?
The vegetative phase (often called “veg”), is the phase of plant growth between seedling and flowering. This is when the plant forms, and your grow light and light spectrum play a crucial role in the plant’s development during this phase.
It’s this phase that the plant develops roots, stem and node spacing,
Most growers prefer their plants to be short and bushy, and the best way to ensure that is by providing your plants enough of the essential blue spectrum they require during the vegetative phase.
Why blue light spectrum is best for the seedling and vegetative growth phase, or maintaining mother cannabis plants:
If you haven’t figured out from reading yet, the blue light spectrum is the best for several plant developments like chlorophyll and chloroplast development, enzyme synthesis, and plant density. It also regulates responses to biotic environmental stresses.¹
Blue light and UV-A wavelengths also trigger cryptochrome and phototropin, which regulate chloroplast relocation, germination, elongation, and stomatal opening, which impacts water transpiration and CO2 exchange.²
In short, the formation of your plant and it’s ability to carry out certain functions in the flowering phase are directly affected by the quality of life it gets in the vegetative phase.
Why pick these grow lights for veg compared to other grow lights for both phases of growth?
When you compare a dedicated veg grow light to a multi-phase grow light, you’ll find that not surprisingly, the multi-phase light has less blue light intensity. That’s because those lights need room for LEDs that emit both blue, and red, and sometimes more.
If you’re looking to grow the best harvest possible, in addition to other factors, I strongly suggest considering a dedicated veg light. If you’re looking for a grow light for your mother plant, you’ll only need one with a blue spectrum, in which case a dedicated blue spectrum light would also be appropriate.
Why do growers want grow lights specifically for the seedling and vegetative phase (veg)?
Growers may decide to buy a dedicated grow light for the seedling and vegetative phases if their current grow light doesn’t emit enough blue spectrum – the spectrum that’s critical to the vegetative phase.
If you’re maintaining a mother plant you’ll only need a blue spectrum, and you’ll need a light that’s emits a blue spectrum that’s intense enough for a full sized mother plant. Having a light dedicated for this purpose is a smart choice.
The different aspect of the seedling and vegetative growth phases that requires an adjusted growing method are these two simple factors:
- The different light wavelength absorbed in this phase (we already discussed that)
- The increased sensitivity to light during these growth phases – which requires hanging your grow light higher than you would during flowering phase. This is why many of these seedling & vegetative phase grow lights emit lower PPFD readings. It’s because if you put too much PPFD on plants in these growth phases, you’ll risk burning them.
Can You Use Red Light During The Vegetative Phase Of Growth?
You shouldn’t use red light spectrums (Red LEDs, or HPS bulbs) during the vegetative phase of growth if possible. The red light may encourage male plant growth, whereas intense blue light will encourage your seedlings to grow as female plants.
What Distance From Grow Lights When Starting Seeds?
Every grow light has a different amount of power, so I advise reading my grow light hang height article. Follow the steps for yourself to determine exactly how strong your grow light is, and how high you should hang it.
Generally speaking, grow light manufacturers recommend hanging your grow light 24-30 inches above seedlings.
If you have a strong grow light above 500 watts of power, you’ll likely need to keep a larger distance between the light and your plants – a rough estimate would be 36 to 48 inches if the grow light were running at full power.
If you were to dim the grow light, that would reduce the distance needed between seedlings and the light.
What Distance From Grow Lights For Vegetative Growth?
For the Vegetative growth phase you need to hang the grow light a bit closer to the plants so they get the proper amount of light.
The exact distance depends on the power of your grow light. A 300 to 400 watt grow light could hang 18-24 inches from the canopy. A stronger light would need to be dimmed or kept at a larger distance above the plants if running full power.
In reality it’s not the distance from the plants that matters. It’s the intensity of light measured at the leaves (read more about light intensity here).
So the logical solution is to determine the grow light height where your plants receive the ideal amount of light intensity for the respective phase of growth: 200-250 micromoles for seedlings and 300 to 400 micromoles of PPFD for vegetative phase plants.
Grow light distance from plants is not a perfect science. You may find your plants react better if your lights are a few inches closer or further than manufacturers’ recommendations.
The good news is if you find your plants start to get burned leaves from being too close, it’s a totally recoverable event, unless you let it go on too long. So check up on them regularly when you’re just starting out.
What’s the best grow light for a mother plant?
The best grow light for a mother plant has a strong blue spectrum with a coverage area large enough for the whole plant.
What light spectrum is best for the vegetative phase?
Blue spectrum is absorbed by plants during the vegetative phase and used to develop the plant’s structure, and prepare it for flowering.
What height to hang grow lights for seedlings?
Most grow light manufacturers recommend 24-30 inches for seedlings.
What height to hang grow lights during the vegetative phase?
For the grow lights mentioned above, 18 inches. In terms of intensity, you’d want a level where light intensity is 300-400 uMols.
What’s the best grow light for a very large vegetative grow space?
The Scynce LED Raging Kush will cover a 5 by 5 foot grow space for the vegetative phase with its fully customizable spectrum.
Is a grow light with majority blue spectrum only good for the vegetative phase?
Yes. You need balanced blue and red light for the flowering phase.