Hi guys, soon I will be moving into new apartment with much worse daylight access. My cacti will have to move too) I'm worried about their future
I couldn't find enough materials on the forum so decided to ask in a post, maybe it would be useful for others.
I've ordered special shelves to be hanged on the balcony and currently thinking about adding special LED growing light. Unfortunately there is no link with English translation, but I will write here all the characteristics.
I'm thinking about this lamp "Ledmax T8-2835-1.2FS". In description stated that it has ratio 4 red diodes to 2 blue diodes, 18W.
Spectrum:
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Please share you thought or experience, maybe there are better lamps and those I chose are not the best. Or completely different approach is needed. Any piece of advice will be useful.
Thanks in advance!
The red/blue grow lights are not the best for your plants, they were designed for low energy consumption. Take a look at the test here: https://www.youtube.com/watch?v=HawgP5SXPko
Hi greenknight, thanks a lot for your help. The video you provided was awesome. After watching it I changed my choise to this guy "Ledmax Т8-IP20-1.2 L 50W", it has 4200K colour temperature, provides 5000 lumens and eats 50W.
That is early spring in Ukraine (pretty cold one this year), I've moved to new place and organized shalves for cacti. They are just starting growing season so I can't tell whether it works well. I'll provide some update later, maybe in summer.
Attached image, maybe would be useful for someone
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You need to get a light meter. There are a few that work well as phone camera apps or a real stand along. It not only light frequency but also lumens(brightness). You can have the correct light spectrum, but if the actual output is not bright enough, it will just cause poor growth. You need at least 10,000 LUX to replicate good bright light. The 2-4 bulb fixtures I use will give me 12,000 lux 2 feet from the bulbs. Distance is equally important since we don't place the light 2" of 50mm from our plants. All the plants are thriving that are under these lights.
With my Samsung Galaxy phone, I found this Android app. to be quit good. https://play.google.com/store/apps/deta ... lightMeter.
I compared this to an older light meter I used with film photography and it worked well. The app is dependent on the quality of the front camera of your phone. It works like crap on my Goggle Pixel Phone.
I'm no expert, however, I use a few different lights and can share some info. At 50 watts, I don't believe you're going to get much output - your shelf looks like 12" x 30" or so.
I have a T5HO, 6 x 4 foot tubes (actually 42" ), The T5HO are fluo's (Hydrofarm 6400K) and put out decent light - I have the light suspended about 20-22" above the plants and my output is about 20,000 lux, measured with a light meter. Total power required at the wall - 324 watts. Each 42" T5HO is 54W.
I keep them at 20" + because at that height, the temperature is around 74 farenheit at the plant level (with 4 fans running - small USB computer type fans) - I keep fans running to keep air moving.
Yes fluorescents run cooler than many others but still throw a lot of heat.
In comparison, in a west facing window in one of my rooms, through glass I get around 40-50,000 lux in the afternoon sun - I live in southern Canada.
I keep my cacti under the fluorescents in winter but keep water to a minimum as I don't feel the 20,000 lux would be sufficient for growing.
I actually use the light with 4 bulbs running most of the winter, and then go to 6 bulbs the month before I am going to bring the plants back to their regular grow rooms in the house.
Important note - in my light setup, to get the output I quote, I have the entire 2 x 4 foot area enclosed by white board to reflect light back at the plants - without this, the light bleeding away to the open room is a killer, it doesn't get to the plants.
I recently purchased a LED light, for the same 2 x 4 foot area (to use with overwintering as well as growing indoor herbs over the winter, cooking not smoking herb :<)) - uses about 300 watts or a little less - output at 28", again with white sidewalls and ends - 51,000 lux, although temps are now at 83F - can get it down 3 degrees or so with a few USB fans that I use on a timer. The nice thing about the LED is that it has a dimmer built in which allows a lot of flexibility.
Depending on what one wants to achieve, the sky is the limit. Here in Canada, either of these lights are $250-$350 - but both using about 300W - to adequately light a 2 x 4 foot area with white reflective walls - like a grow tent.
Good luck.
These days you don't need special grow lights. All you need to do is go to any hardware or lighting store and grab some LED downlights.
The key is CRI, lumens and lumens per watt.
CRI or colour rendering index is a percentage figure for how well the light source replicates the visible light spectrum of natural sunlight. Even cheap LED downlights are hitting 80% these days. I you want better (though you probably don't need it) you can buy more expensive lights designed for art galleries and get anything from 95 to 99%.
I won't explain lumens and lux as it already has been explained.
My point though is you don't need fancy grow lights these days and can use stock LED down lights instead. The only issue is lumens/watt. Cheap downlights might only get 80 to 90 lumens/watt while best in class will get 150 lumens/watt. So you need to calculate based on your local electricity prices if buying expensive more efficient lights is worth it or not.
Don't waste you money. Unless you pay nothing for electricity it's not financially worth it to even replace fluoro tubes in existing setups these days.
I'm using the växer grow lights setup, from ikea (sorry for the publicity, but they don't sell them anymore ) I was able to buy some second hand, and I guess they are basic led growing lights, probably nothing high value, nothing fancy, but my seedlings do great under them and for the rest I just use them to add some extra light during the dark winter, in addition to what comes through the window. Also I have used some aluminium coated inuslation to reflect the light back at the plants, it helps.
I got confused between the very similar thread and this one. I should have posted this here, as it is about LED light measurement:
This article reports the poor results of phone apps compared to a proper überprofessional meter for measuring light from white LED lamps.
"Therefore apps are unfortunately not really of any great assistance for measuring illuminance and not even any use to obtain a general idea of the illuminance value. On the contrary: They lead the user in the completely wrong direction." https://www.dialux.com/en-GB/news-detai ... lluminance
The light meters that are designed for measuring ordinary LED lamps are dear enough but the ones for measuring single-coloured LEDs are about twice as expensive. Some of those have switching for each of 9 colours, including purple.
I don't know if the apps are of any use for measuring fluorescent light output but I don't use fluorescents.
Hi everybody, thanks a lot for so many valuable advices, I really appreciate it.
After all posts I decided to dig deeper. So I bought the lux meter and found out that numbers from my wife's super fancy Huawei differed significantly especially at the places were light falls the most (in some cases 2 times higher ) So what I got. From the image I've posted above you could see that I had 3 rows. Middle row showed numbers around 9000 lux, side rows around 6000 lux.
Some thinking later I took the covering from lamps away and numbers increased. In the middle row jumped to 12000 - 14000 lux, side rows 9000-10000 lux.
My setup is pretty cheap - 8$-9$ for a lamp, unfortunately I don't have possibility to change it right now. Have to stick to it, at least for this year. I turned on it for 10 hours a day + it's a balcony and I have 2-4 hours of western sun (rest blocks nearby building), not the best one, some cacti get better and more, as they are closer to the window, some have a bit less. I really hope I wouldn't spoil my cacti. I will post some updates once a month or two. Maybe it would be useful for someone.
) So what I got. From the image I've posted above you could see that I had 3 rows. Middle row showed numbers around 9000 lux, side rows around 6000 lux.
I took the covering from lamps away and numbers increased. In the middle row jumped to 12000 - 14000 lux, side rows 9000-10000 lux.