2 700K for plants

[Sean_Buckley]

Is 2700K good for plants?
Sean

 

[opiesilver]

Nope. You need somewhere between 5000K and 10,000K.

 

[Sean_Buckley]

Will they do OK at all? Or did I waste a trip in and $8. I bought it because a regular 4' bulb at my LFS was $30.
Sean

 

[Discomafia]

Nope. You need somewhere between 5000K and 10,000K.

It's actually 5000-6700 for plants, as at that kelvin rating, the light is similiar to that of the sun.

My plants were growing well with these bulbs, and they were 2700K as well, but yours are different.

 

[konrad05]

Nope.  You need somewhere between 5000K and 10,000K.

It's actually 5000-6700 for plants, as at that kelvin rating, the light is similiar to that of the sun.

My plants were growing well with these bulbs, and they were 2700K as well, but yours are different.

Yep.

Stay away from 2700, even though it says the bulb is for "plants".

 

[kenneth_kpe]

research on the bulb your gonna buy chances are by searching a little in the net you could find its spectral distribution table and compare it with good plants bulbs, it will help you pick a good bulb but be careful!! good bulbs are also sometimes good algae bulbs look at my tank haha learned the hard way

 

[George Farmer]

Light is a complicated subject but I'll do my best with my limited knowledge.

I would say the light spectrum peaks of the bulb are more important than the colour temp. (K).

Plants photosynthesize most effeciently with the blue and red parts of the spectrum. Generally speaking the higher the colour temp. the "bluer" the light and the lower temp. the "redder". This is a generalistion though. Bluer (higher K) tend to be used in marine setups as the light simulates the deeper ocean where the red part of the spectrum is lost. Algae also tends to thrive better in this light. An equal balance of blue and red (white) is provided by 6500K which is close to the sun at noon at the equator. A lot of 6500K (Daylight) tubes are full-spectrum meaning they have three peaks their sprectral output. Most high-quality (and price) tubes will have these 3 peaks (red, green and blue) provided by a tri-phosphor coating inside the tube glass.

Your 2700K bulbs will peak in the red/orange part of the spectrum but will have virtually no blue I would guess. This may be ok if you have enough intensity. One advantage is that algae growth should be limited. If they were fairly cheap then you'll probably have limited success. Give it a try and see. Use a reflector to increase intensity if you're not already.

I have three 3000K (Dennerle Special-Plant) bulbs which I find excellent. These are however high-output tubes with and the spectrum peaks in mostly orange/red but also a little in the green and blue. They give a warm, almost orange light so I've balanced this with some whiter tubes (6700K and 7500K).

Sorry if I've gone on a bit, hopefully I've answered your question.

 

[opiesilver]

Nope.  You need somewhere between 5000K and 10,000K.

It's actually 5000-6700 for plants, as at that kelvin rating, the light is similiar to that of the sun.

My plants were growing well with these bulbs, and they were 2700K as well, but yours are different.

Plants can and do use the spectrum provided between 5000K and 10000K. Please don't confuse a 10000K bulb with an Actinic bulb as they are not the same at all.

With the 10000K bulbs your plants use more CO2 because the plants are able to use light in the 660-700 nm range more efficiently. There are two special chlorophyll's, P680 & P700, that use this spectrum of light. Light in this range is best in a watt to watt growth yield. However, blue light allows more CO2 in enter the plant since the stomata open even larger when the plant is exposed to blue. The blue wavelengths contain very little red then the plants will grow slower but more compact and bushy. A red, or cooler bulb, 5000K, is more heavily weighted toward the red wavelength and containing very little blue will cause plants to grow really fast and leggy (large distances between nodes).

So ideally you want a combination of the two ends of the usable spectrum for your plants. You can mix 10000K and 6700K with very good results.

Hope I didn't just go to geek for anyone.

 

[Nospherith]

I don't feel as bad about owning a 10,000k bulb anymore. thanks opiesilver, that was very informative.

 

[Discomafia]

Thanks for that post, all news to me.

 

[George Farmer]

A red, or cooler bulb, 5000K, is more heavily weighted toward the red wavelength and containing very little blue will cause plants to grow really fast and leggy (large distances between nodes).

So ideally you want a combination of the two ends of the usable spectrum for your plants. You can mix 10000K and 6700K with very good results.

Very interesting post. Are you saying that my plants will grow even more bushier wither higher colour temp. bulbs? At the moment I have 61W of 3000K, 20W of 6700K and 18W of 7500K. Perhaps swapping one or two 3000K bulbs for 10000K would give me even better growth.

 

[Silly me]

since blue light is available deeper under water doesn't blue make the plant grow to the surface and as more red get available close to the surface, the red lights cause the plant to slow down the fast and leggy growth the be more bushy..???

 

[George Farmer]

I think I'll stick with my current lighting, it works well. If it works don't fix it.

 

[vidiots]

I have both 6500K and 9600K bulbs on my 55gal tank. The plants seem to do well. I think that the 6500K bulbs are most pleasing to my eyes. The 6500K bulbs have a very white natural sunlight look to them. The 9600K bulbs have a very slight pinkish-violet appearance to them (I guess the tint should be bluish or violet, but looks pinkish to me, wife says I must be slightly color blind). The 2700K bulbs have a noticibly yellowish tint to them if you look at the same watage all side by side.

 

[opiesilver]

Hey guys, the idea is to find what looks good to you. The plants for the most part could care less as long as it's a usable spectrum. If your plants a looking leggy do some research on the species. It's not always caused by your lighting choice, but a higher kelvin bulb does produce shorter growing plants. There have been several studies done on this and the results are very reproducible. Beside both myself and the rest of the AquariumPlants.com staff have learned this the hard way over the last couple of years. We have been trying many different lighting options on our 125 65g tanks in the warehouse. The light the gives us the best results are the 10000K daylight bulbs. They give the plants that nice stocky (eg..healthy) look. The red plants grow just as red and the green plants just as green. The only real difference is the the plants don't tend to grow lanky, with the exception of an unnamed species of water oak.

But saying all of that, find the lighting you like to look at first and foremost.