Help choosing led

Hi. I've got an old black dog 600. It's a blurple. I was thinking my grows might be better with a more white led light. At least that's what im.always told when people see the blurples.

I have a 4x4 tent. What do you guys think would be a good light for this? I tried research online but I'm not really sure what info to trust. Any recs for what I should be looking at?

Also, if I get one of these white leds, should i use my current light for side lighting? Or is the new led going to be enough?

Also, I'm not looking for the cheapest. I'm looking for good light penetration and happy plants! Thanks!

My favorite fixture is my viparspectra bar light

tbh if i was in the market for lights or anything i would cruise grow journals, lots of indoor grows here that say what they grow with, just my 2 cents, currently i have a few spider farm lights, but i do most of my growing outdoor now adays

Heh, blurples rock(ed)! I had a Kind LED back in the day but switched to newer designs back in 2021. Even since then, things have changed a lot.

I've spent a lot of time learning about grow lighting and I admit that not all growers have my same level of enthusiasm.

If you "just want to grow some weed", pretty much any light will do. If you stay with a name brand, you really can't go wrong but there are significant differences between various models.

I think of it as being in two categories — "I just want to grow some weed" vs "I want a light that's going t allow me to get excellent results".

New lights have a very even light cast ("PPFD map") but some lights are more even than others. Blurples had a significant "hot spot" and a fair number of modern LED's have a hot spot, though not to that great an extent.

This is the PPFD map from my Kind blurple (2' x 4' and with a hang height of 18"). Lots of light right in the center but, just a few inches off center and there's not much light. Oh, PPFD, is the number of photons of light falling on a square meter in a second. I abbreviate it as µmol. So that's 642µmol but only 91 around the edges.

600µmol is considered the minimum needed for flower. Cannabis dies below 70 and maxes out at 800-1000 (or so).


A lot of board style LED's sold as "HPS replacements" and most (all) board lights will have a "hot spot". Those designs are less expensive to produce and they put out a decent amount of light. There's no question you can grow a good crop using those lights.

Board lights are cheaper to design and manufacture but their PPFD map is not as even, they run hotter than board lights, and they don't have the same level of digital integration as a lot of bar lights.

Some bar style lights have a more even PPFD map. The advantage of that is that you have almost as much light around the edges and in the corners as you do in the center. If you want to grow a "full tent", that's a good thing.

The PPFD map for this light is, in a word, stellar. Mars did a great job. It's generating almost 1300 in the center and most of the edge area is >1100. That's excellent. And this light is $430 or so. Cheap. You won't use 1300µmol but when you turn the dimmer down so that it's 900 in the center, it's still 900µmol± around the edges. That's important, if you want to grow a lot of plants or "fill out the tent".


If you want to grow different strains or if you want to do a "perpetual grow", there's a strong argument to made for getting two lights. One, you get redundancy but, more importantly, it makes it easy to deal with multiple plants that may have very different canopy heights. That could happen even if the plants are the same age or it will happen if you run a perpetual grow.

If I were growing in a 4' tent and wanted two lights, I'd go with a pair of Spider G4500's. They're about $220 each, they generate a lot of light, and have an excellent PPFD map.

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If you're willing to spend serious $$ and want to go with a prime product, the GrandMaster LED Tarantula Explorer for $949 has an incredible PPFD map and has a tunable spectrum.

Full disclosure—I own lights made by Vipar, Spider, Mars, and Growcraft but have no affiliation with any of them.

Delps8 said:

Heh, blurples rock(ed)! I had a Kind LED back in the day but switched to newer designs back in 2021. Even since then, things have changed a lot.

I've spent a lot of time learning about grow lighting and I admit that not all growers have my same level of enthusiasm.

If you "just want to grow some weed", pretty much any light will do. If you stay with a name brand, you really can't go wrong but there are significant differences between various models.

I think of it as being in two categories — "I just want to grow some weed" vs "I want a light that's going t allow me to get excellent results".

New lights have a very even light cast ("PPFD map") but some lights are more even than others. Blurples had a significant "hot spot" and a fair number of modern LED's have a hot spot, though not to that great an extent.

This is the PPFD map from my Kind blurple (2' x 4' and with a hang height of 18"). Lots of light right in the center but, just a few inches off center and there's not much light. Oh, PPFD, is the number of photons of light falling on a square meter in a second. I abbreviate it as µmol. So that's 642µmol but only 91 around the edges.

600µmol is considered the minimum needed for flower. Cannabis dies below 70 and maxes out at 800-1000 (or so).
View attachment 5475328

A lot of board style LED's sold as "HPS replacements" and most (all) board lights will have a "hot spot". Those designs are less expensive to produce and they put out a decent amount of light. There's no question you can grow a good crop using those lights.

Board lights are cheaper to design and manufacture but their PPFD map is not as even, they run hotter than board lights, and they don't have the same level of digital integration as a lot of bar lights.

Some bar style lights have a more even PPFD map. The advantage of that is that you have almost as much light around the edges and in the corners as you do in the center. If you want to grow a "full tent", that's a good thing.

The PPFD map for this light is, in a word, stellar. Mars did a great job. It's generating almost 1300 in the center and most of the edge area is >1100. That's excellent. And this light is $430 or so. Cheap. You won't use 1300µmol but when you turn the dimmer down so that it's 900 in the center, it's still 900µmol± around the edges. That's important, if you want to grow a lot of plants or "fill out the tent".
View attachment 5475329

If you want to grow different strains or if you want to do a "perpetual grow", there's a strong argument to made for getting two lights. One, you get redundancy but, more importantly, it makes it easy to deal with multiple plants that may have very different canopy heights. That could happen even if the plants are the same age or it will happen if you run a perpetual grow.

If I were growing in a 4' tent and wanted two lights, I'd go with a pair of Spider G4500's. They're about $220 each, they generate a lot of light, and have an excellent PPFD map.

View attachment 5475330]]]]]

If you're willing to spend serious $$ and want to go with a prime product, the GrandMaster LED Tarantula Explorer for $949 has an incredible PPFD map and has a tunable spectrum.

Full disclosure—I own lights made by Vipar, Spider, Mars, and Growcraft but have no affiliation with any of them.

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Wow. Thank you for the explanation of things to look for and the recommendation. I really appreciate your effort.

purelydebased said:

Wow. Thank you for the explanation of things to look for and the recommendation. I really appreciate your effort.

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Not that I have opinions, of course!

Do you plan to grow with a full tent? Do you plan on doing a net/scrog with an even canopy, or possibly doing multiple plants of different heights?

What kind of lights you get depends on your grow style and your specific needs. A single bar-light is unbeatable for a big and even canopy. Multiple lights allow for different heights of plants and/or different strains and phenos.

I have 2 250 watt light panels in a 5x5 tent, where most people would recommend 750 watts or more. I’m doing pretty well with my setup. I don’t fill the entire space and don’t need any more light. I can also run a variety of plants and move the lights around as needed, and I’d rather have that flexibility, than a “better” light.

purelydebased said:

Hi. I've got an old black dog 600. It's a blurple. I was thinking my grows might be better with a more white led light. At least that's what im.always told when people see the blurples.

I have a 4x4 tent. What do you guys think would be a good light for this? I tried research online but I'm not really sure what info to trust. Any recs for what I should be looking at?

Also, if I get one of these white leds, should i use my current light for side lighting? Or is the new led going to be enough?

Also, I'm not looking for the cheapest. I'm looking for good light penetration and happy plants! Thanks!

Click to expand...

Which rev of blackdog ? Theyve been updating and are now using heavily supplemented white for their new gen. they have somewhat low efficiency but about 50% better than what they were a few years ago.