foliar feeding
 

I know some people don't believe this works but for those of you who do this religiously.....have you seen a difference in your leaves? Are there any particular types of orchids that benefit from foliar feeding. I also read about spraying the undersides of the leaves to get it best absorbed?

Also is it a different concentration of fertilzer solution used for foliar feeding or same as what you would use to water the medium of the plant?

I use this method constantly ...LOL every day.

I use excatly the same mix I use to fert with "I grow S/H so overwatering is not a issue" and yes the underside is the side for plants with waxy shiny leaves that will be best for this.

They have done studies with radio isotope tracers that prove the chids do get nutes this way also> I just read something on it recently on springer link

as far as differences go the only thing I can say is my catts each have three eyes in active growth at once .....But s/h has a lot to do with the fantastic growth I see too.The other thing you have is the white build up you will get on leaves folair feeding is going to cause some issues in how clean the chids will look ....Its not really harmfull but it can be unsightly

Thanks, John! I appreciate the info.

I have always done this so I can't say I've seen a difference whether it is done or not, but I have never had any problems doing it.

Being a slipper specialist I read a lot about them, and I can say that such esteemed slipper growers and breeders as Harold Koopowitz are big believers in foliar feeding for Paphs and Phrags specifically.

Hey Joe, nice to see you back on OB. I've been wondering about the foliar feeding thing mainly because of my kovachii hybrids. I guess I tend to grow them in higher light and perhaps that is why the bottom leaves tend to get yellow. higher leaves look really the "right" green. I can't fertilize the media more since alot of phrags can sensitive to it. So I've been trying to spray the bottom yellow leaves or starting to yellow leaves to see if it makes a difference.

I was just wondering if everyone uses the same concentration of fert/water as what they'd use to water the media. Sounds like the answer, is yes.

Well yes - the way I do it is when I water/fertilize, I drench the leaves. Now I know that many would say "You drench the leaves?! Don't the crowns rot from water getting trapped in the growths?". But rest assured, I prevent rotting by watering in the morning, and maintaining excellent air movement, so that the leaves dry off quickly.

Growing in high light, if it were the reason for your plants' yellowing, would give yellowish top leaves as well. Are you growing the plants in s/h? Is it just one or two of the lowest leaves yellowing or are many yellowing? How old are the plants?

I got them as seedlings last winter. It's just the bottom leaves that are getting old, turning yellow. Do you think it's not the light issue?

No I wouldn't say it has anything to do with light if the upper leaves are still green. Most likely the plants are just losing their lower leaves naturally to allocate resources to the growing parts. As long as the new leaves are maturing larger than the older leaves, the plants should be fine.

Without studying heaps of variables about how you are growing your plants, the light, yadayada...
Yellowing of older leaves in many families of plants is caused by plants relocating mobile nutrients. Nitrogen gets moved from old leaves to new leaves.
Low nitrogen (sort of) equates to good levels of phosporous, potasium & the traces - this is fine, the trade off is lush foliage vs. flowering.
Don't worry about OLD leaves yellowing ;-)
google plant nutrients for peace of mind,
and watch those NPK ratios on the fertalizer packs
have a bloomin' good time ;-)

I just saw that this was a thread about seedlings...
my bad!
the comments above relate to flowering size plants.

For seedlings you want more nitrogen than for mature. keep that foliage as long as you can. Foliage leads to photosynthesis in the early stages of life... which leads to faster growth, BUT only if ALL plant nutrients are present.


Stomates (openings from the inside to the outside atmosphere )are on the under side of leaves. that's where absorbtion will occur.

:) good luck

Thanks for the info guys. The reason I thought it was a light issue is because I read the following somewhere...

When light is increased, bottom leaves my start to yellow because nutrients are mobilized to other parts of the plants. The roots may not be able to take up nutrients fast enough. This is when foliar feeding may be important.

That was the jist of it.

BTW, Joe, forgot to answer your question. I have them growing in CHC/charcoal/perlite mix right now. When I first got them, I put them in S/H. Although I was flushing, I learned, flushing them the CORRECT way takes ALOT of water. I moved them to rockwool to experiment since one of the parents (kovachii) grows in association with decomposed limestone. I had roots all over the place but it's hard to maintain proper pH with rockwool over time so I think they started complaining again. Around the end of Summer, I moved them to the CHC mix. They're growing fine now, aside from the yellowing bottom leaves. I've done enough experimenting with them and will leave them alone now before they tell me to piss off for good.

Definitely what you read is true. However, I wouldn't say your plants are getting too much light. It sounds to me like they are getting just what they need.

Tracy;

From a purely horticultural persepective, I agree with everything that's been said. Most likely, the yellowing and loss of older seedling leaves is due to age, change in environment, and translocation to newer growth.

Foliar feeding generally is used commercially for one of two reasons:

1. Ease of application, where the grower believes that foliar application of nutrients using a spray wand is faster, less labour intensive, and cheaper than individual application to the pots.

2. To correct nutrient defficiencies discovered either by observation or tissue analysis. Foliar application provides for more rapid nutrient uptake and distribution throught the plant than application via the substrate and root uptake.

If you are applying nutrients appropriately, foliar application should not be needed.

Cheers.
Jim

Hi Jim:waving Does this apply to ALL orchids in general. Or is it just the ones with the thinner leaves? For example, certain varieties of neos and sedireas have very thick leaves. Does the foliar feeding benefit them in any way? Another long time grower was telling me some of those neos probably don't take up nutrients via foliar feeding due to their leaves being so thick.

In my current temps, RH, etc. I flush the phrags with RO every 2 or 3 days. They get fertilized once weekly with either 125ppm of MSU or 2 T Green Jungle/ gal of RO. Most of my stuff is mini Japanese species, which don't tolerate a lot of fertilizer if grown in moss. I use an organic Japanese fertilizer called Biogold for them. So as far as proper fertilizer application for the phrags and paphs, I've no flippin' clue if I'm doing it right. :dunno:

Sounds fine to me. I fertilize my Phrags weekly too, but at a higher TDS and they do fine as long as I flush with RO water, just as you are doing.

As for Paphs, they can generally take quite a bit more salt than Phrags. I flush them out only once a month, and water with tap water.

Tracy;

It applies to all plants. With foliar feeding, the nutrients are absorbed through the stomates, or pores, in the leaf surface throughout the plant and don't have as far to travel to be distributed. You're basically bye-passing the stem. Leaf thickness doesn't really matter. It generally appears that you get faster results in thinner leaves because being thinner, you see changes in colour or appearance more quickly.

Cheers.
Jim

I foliar feed all my cymbidiums mature plants and seedlings During the winter I will drop the nitrogen content of the feed so the i dont have fungal problems On warm summer nights I will foliar feed my plants adding Ammonium nitrate to the mix so as to raise the nitrogen levels. The leaves are sprayed top and bottom . Just to be sure I also add a wetter and a small amount of fungicide to the mix

Thanks, Jim and Des.

Joe, what ppm are you fertilizing your phrags at?
My paphs I only water once or twice a week and fertilize once a week. Is it just the calcerous paphs you water with tap, or all your paphs?

My Phrags, and all other plants, are fertilized at 150ppm + the TDS of the tap water (appx. 225ppm), so ~375ppm.

All of my Paphs are watered with the 225ppm tap water. I add lime to the calcareous Paphs' potting mixes too, though this is not necessary.