Grow Light Search

Greetings grow family. So I recently finished my first grow and am still a rookie.

I am in the market for a 4x4 flower light.
I ran a Vivosun vs4000 in the 4x4 but I don’t believe that light is optimal for flower but I think its a good veg. light.

My plan is to veg in the 3x3 and flower in the 4x4.

I been looking at Grow Light Science ProGrow640 and the new Phoenix680 by Spectrum King. These lights are around my budget.

Can anybody with knowledge on this topic please chime in?

I been bearing negative comments about Spectrum King but if you let them tell it they are more advanced than their competitors.

Folks I am permanently disabled and only get paid once a month.
Every purchase I make is a sacrifice. I need dependable equipment built to perform and last!

Your assistance is greatly appreciated!


@dbrn32 is our lighting expert and he should chime in soon but for my 2 cents i would do some further research into a ppfd map from both light manufacturers to get a better comparison between the 2.
Rule of thumb for watt/sq ft:
Low efficacy, generic “Amazon” lights (PPE: ~1.0 µmol/J): 50-60w/sq ft (525-640w/sqm)

Medium efficacy, “housing”-type lights (PPE: ~1.5 µmol/J): 30-40w/sq ft (320-430w/sqm)

High efficacy, panel with quality diodes (eg. Samsung, Osram), or (Cree) COB-type lights with high-end driver (PPE: ~2.5 µmol/J): 25-30w/sq ft (265-320w/sqm) <---- ideally your gonna want one that falls into this category

1 Like

I know this site has a sale going with the Progrow640, free controller with purchase.
If that helps you choose between those 2 lights.


Impressive light.

1 Like

Thanks so far folks. 1Happy Pappy I was on that site earlier and saw the promo. Sounds good.

I will need to make a decision soon as I just started a new grow.

I was really leaning towards Spectrum Kings Phoenix680 but then I heard negative comments about the company but I dont know if thats a fair statement or a low blow.

1 Like

This because spectrum king has history of having mediocre lights that they claimed were better than everything else since they’ve been around.

I would reach out to both and ask them to provide integrated sphere report with certifications. If they meet advertised specifications either should do plenty good.

Good :sunrise:, and thank you very much for this information. Now I know the truth about Spectrum King. I will not make the same mistake twice and that is, buy online before researching. With no experience I bought a grow kit. Not bad but I am a little smarter than that.

As some advice to new growers like myself. Reach out for assistance, research and don’t buy spontaneously. The excitement of getting your grow going can interfere with an intelligent decision, leading to wasted dollars and disappointment. A little patience will be rewarding.

This information is more so for me for future reference :joy:. True talk though!

So I will contact these companies and politely drill them on there products, see what kind of customer service I get in addition to the facts about there grow light.

Also, is Grow Light Science a reputable company and do you have any recommendations on a LED Grow Light for a 4x4 tent?

Thank you,
Happy Growing to y’all

1 Like

I just bought an hlg 350r which may be a little smaller than you’re looking for, but I had some questions about it, and sent them a couple emails. They responded immediately which I was very impressed by. Top notch customer service. If that matters to you, you might take a look at their lights.


:100: Truth good luck on future grows.:+1:

1 Like

Thank you for your input. I will look into them!

Definitely! I ended up buying another Vs4000 to finish the grow. Now I have an extra light that cost 4 something. The flower light is 7 something. I can sell or keep the light for down the road but money was wasted immediately despite it paying off in the long run.

1 Like

They are relatively new as far as i know, so not really sure. Best bet would be find a couple people with journals using them and follow along.

Horticulture lighting group has really good reputation, i usually point people there because I’m confident lights will perform as expected.

I have four 4x4 tents running. As far as lights , in one I have an HLG 650rspec, in another I have 2 Grow Light Science 300’s (300 watts each), in the 3rd tent is a GeekBeast Pro 630 watt, and in the 4th tent are 2 Budget LED 240 watt lights.
My grows are from clones from my mothers, and all tents receive the name nutrient regiment, and in the same environment. The 2 Grow Light Science 300’s have consistently given me the largest yields, and tightest buds, with the GeekBeast Pro a close 2nd. The HLG is not to shabby either, but the Grow Light Science definitely outperforms the others. If I was starting over, I would go strictly with Grow Light Science. Hope this helps with your decision.

1 Like

Good evening thank you once again for your assistance!

I did look into the H L G 650 R Diablo along with the lights mentioned earlier and also Vipar Spectra ks5000, Mars Hydro650, Grower’s Choice ROI-E680S, and a few others over the past month or so and I decided on Grow Light Science ProGrow640.

I chose this light based on a long conversation I had with a Sales Rep. (Eric) from LED Lights Depot. He also tests lights on you tube. I explained my situation and after helping me choose a light he reminded me that I have 120 days to decide to keep the light or not and that I could return it for a full refund with no questions asked if I am not impressed with the lights so long as there is no damage. He also broke down other lights that he was familiar with. He admitted he does not know every light but had a good idea from what I explained to him, what would be best for my situation. He also broke down Spectrum King’s Phoenix680. He said you can’t go wrong with either light and that Spectrum King has gotten much better than previous lights but suggested the ProGrow640 for my situation. I did ask for the I S R with certifications and he said that the companies never supplied them with those but he would look into that and suggested that I contact them as well but also noted that a lot of companies are now more accurate with their performance claims as they can be called on it.

Also I watched Shane from Migro on you tube and while he did not review the light I chose, he did review the ProGrow850. Shane has reviewed over 100 grow lights and also sells lights (Migro). I have been watching his channel for several months.

He states was so impressed with Grow Light Science that he reached out to them and is now carrying that brand over in Europe.

For whatever that is worth, I guess I will soon find out.

Well I wanted to share my grow light search with you all. There are so many companies with lights out there that you could probably search for a year without making a decision, so I made one.

Peace & Happy Growing
To Y’all

1 Like

Thanks Otis your information helps to confirm what I have found out about Grow Light Science. They seem to be producing high quality lights.

I chose Grow Light Science ProwGrow 640. A gentleman named Kevin from Grow Light Science called me this morning and spoke in detail about the company and the light I purchased. He told me even though I went through LEd light depot that if I have any problems with this light to not hesitate to call him. He also stated that all of their certifications and data are available online.

I must admit I was impressed. Before he started talking I told him that I purchased one of their lights yesterday, from a 3rd party. That was by design, I figured he would thank me and go about his business. To my amaze Kevin asked me what did I purchase, asked my full name and I guess he found my order and told me I should have it by Thursday. Explained the light to me and also offered any assistance I may need.

He asked me why I didn’t contact them directly and I told him I wanted to hear info about their lights from someone who carries. Lights

Seems pretty cool.


Hit the button by mistake. I wanted a sort of 3rd party critique from someone who sells different brand lights.

Thanks for some of your input. Helped me make the decision to go with 2 pro640s.


You are looking good there my friend.
What strain/strains? What height and dimmer setting are you running at.
Also how was the customer service?

Green kush photos and 1 bubblegum auto and 1 blue dream auto. Just set these up so not dialed in yet but running 100 percent at 20 inches. Too close? Customer service was great and delivery very prompt.

Do you think running closer at less intensity is better or further away at higher intensity? :thinking: