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Nitrogen deficiency

All my Nepenthes that I grow indoors under lights seem to all have a yellowish color to the leaves. The ones I grow outside all have nice green leaves but only receive bright indirect light. Are the plants that I grow indoors yellower because of brighter lights or are they showing signs of a nutrient deficiency. If so, what can I do about it?
-Nick
 
I get a yellowish look to the leaves as a result of the plants growing very close to lights (within 4").  I received a N. ventricosa that had large green leaves initially, and the new leaves that formed were only 3" and very yellow.  However, the pitchers were much larger and more colorful. I moved the plant further from the lights, and the new leaves were green.  I received N. x red leopard from Tony on last Thursday with bright green leaves, and now the new leaves at the top have turned golden with a flush of red.

My guess is that it's the light, but it seems strange because sunlight should be even more intense.  I don't associate the yellow color to be a bad sign (in my case atleast), but I could be mistaken.

Brian
 
Plants will form darker green leaves with less light in order to absorb more light to create chlorophyl. Yellow leaves in other plants is a sign of iron deficiency. I would try a nice foliar feed with epiphytes delight or other orchid fertilizer.
 
Yellow leaves can be a sign of virtually anything--bright light, overwatering, underwatering, nutrient deficiency, pathogens, non-optimal humidity, too hot, too cold....etc.

But, with that said, I grow all my neps under fluorescent lights and some develop yellowish (and sometimes reddish) leaves. In my case, it's probably the light because I foliar feed with an orchid fertilizer once per month, and my plants are growing and pitchering like mad so I believe they're well fed.

Why don't you try foliar feeding once per month with an orchid/epiphyte fertilizer diluted to 1/4 the recommended strength? It's pretty safe with neps and I would recommend you place your plants in lower light while they're absorbing the liquid as some species can have their leaves slighly burned if placed under bright light with lots of water on them.
 
Could it be any problem with the light bulbs you use? Perhaps using bulbs made specifically for growing plants could improve the coloring. I've noticed a similar yellow leaf problem with some of my Neps and thought it could be due to the lights I use (I use T8 bulbs with a color temperature of 6700K). Anyone else got an opinion on that?
 
I try to judge the color of my leaves by the photos of wild Nepenthes I see.  I haven't seen too many wild Nepenthes with bright green leaves like the artifically fertilized plants.  The wild Nep. leaves are usually flushed with gold, red, or purple.  

Try a simple experiment:  Take an outdoor plant with green leaves and put it under the lights to see what happens.  Likewise, an indoor plant can be placed outdoors.  

On another note: I feed my plants on a regular basis with fresh insects. I notice a growth spurt, with larger leaves/pitchers, but the color of the leaves remains the same. I don't see a dark green color develop.

Brian
 
Bah! I threw away a few Neps a while back because their leaves were turning weird colors...Now that I read this they probably could have been saved
smile_h_32.gif


It seems many Neps in my terrariums under very bright light aquire yellowish leaves. Some of them produce pitchers like crazy and some aren't doing so well. I'll definitely have to look into this further.
 
[b said:
Quote[/b] ]Perhaps using bulbs made specifically for growing plants could improve the coloring.Anyone else got an opinion on that?

I exclusively use T12 cool white fluorescents, largely because I have trouble finding warm whites. Most of my plants have done fine under these and for those that haven't, I'm inclined to believe excessive temperature was the culprit. I'm not saying a combination of warm/cool whites isn't better (it probably is)--I'm just saying that I'm perfectly satisfied with how my plants are doing under cool whites only. As for leaf coloring, I can think of reasons why using a mix of cool/warms would produce a difference in coloration, but I can also think of reasons why it wouldn't.

I'd be interested in knowing if anyone's done a controlled experiment that looks at growth rate, pitcher formation and coloration under cool whites vs. cool/warm combo.
 
That would be interesting, I use T12 cool whites also. I haven't fed my plants in a while I am going to get some crickets this weekend. I do fertilize ever month or so with orchid fertilizer so it must be the light intensity. Thanks or all the suggestions.
-Nick
 
  • #10
You guys should get t-8's they're more efficient and output more lumens.
 
  • #12
[b said:
Quote[/b] ]You guys should get t-8's they're more efficient and output more lumens.

The t-8's I see around here put out less lumens than t-12's. I use a combo of cool white and daylight. The initial lumen output for a single bulb is around 3150. The color temp for the daylight is 6500K and for the cool white it is 4400K (or something in that ballpark). On the otherhand, the t-8 cool white has an initial lumen output around 2200.

What's the lumen output for your t-8s?

I would really like to get t-5s, with the initial lumen output of 5000 for a single bulb. If you use 6 bulbs you'll get 30,000 lumens, which is very close to a 400watt metal halide.

My leaves have a healthy glow to them. I'll try to take some photos.

Brian
 
  • #13
[b said:
Quote[/b] ]You guys should get t-8's they're more efficient and output more lumens.

This is true for some brands but, unfortunately, like Brian, the T8s sold in my area have the same lumen output as the T12s but cost more! I should probably do an online search of good brands and ask the clerk to order those.

[b said:
Quote[/b] ]I use compact fluorescents

I do as well for hanging plants and others too big or otherwise unsuitable for grow racks/terraria. There's nothing wrong with these, but you have to be more careful about overheating/burning your plants as they get MUCH hotter than the tubes. Also, if you're putting them over small (10gal) terraria, you may want to consider placing 4 10gal terraria side-to-side and covering with a single or even two 4' fixtures. You would get good light at a fraction the setup cost.
 
  • #14
Chloroplast: You bring up an interesting point about compact flourescent temperature.

All of my terrariums are 10 gallons and under and I use compact flourescents on all of them. The tanks do get pretty hot, especially during the summer, which sometimes has some bad effects on some of the newer arrivals to my collection. However, once the plants get used to the heat, they're usually fine.

The thing is, I would love to use flourescent tubes, but I just don't have the space for them right now. I keep all my plants in my room, so 4 foot fixtures wouldn't exactly be space efficient. I really wish that companies would make tube fixtures of all sizes (ones that don't need all the weird wiring that you can get at Home Depot). Just a cheap fixture that holds perhaps two 20 watt tubes and can just plug right into a wall out of the box. Is that so much to ask?!

The point is that I'm stuck with compact flourescents. The good thing is that they work well for the most part.
 
  • #15
I just bought some single tube 20 W 2' long flourescents w/ fixture that just plug into the wall at Walmart. Less than $10, and it comes with a "grow" light for plants and aquariums. Check out their flourescent lighting section. I put two of them on top of a 10 gallon tank.
 
  • #16
Really? Dang, I might have to go check that out! Do you plan on using the tubes they came with or replacing them with something else?
 
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