Foliar feeding

[fxxy]

OK, once and for all, what is the real story on fertilizing orchids by applying fertilizer to the leaves????????? . I've seen opinions in both directions, BUT no results of studies by anybody attesting to the efficiency or lack thereof of this practice. Is there any literature on this subject?? Does anybody have any experience with long term use ???? I would really appreciate any feedback on this. I eagerly await your words of wisdom....

[Cjcorner]

If you are going to spritz your plants i'd suggest you do a regular program of spraying an anti-fungal/anti-bacterial. Plastic bottles end up growing bacteria in them if they aren't cleaned and disinfected on a regular basis. If you want to give them some mist, i'd recommend you sit them outside and mist them where air movement can dry them off. Fertilizer is best put on roots in my experience. I'm sure there is someone that will disagree with me...I used to do the spritz thing myself. Over time though I gave it up as I lost plants to rot because of it. If you want to find an easier way to fertillize I would recommend one of the time release fertilizers such as osmocote. I recently saw where someone had sewn small mesh u-shaped pockets that hold time release pellets. Inside is a wire sewn in so you can hang it around a plant, such as a vanda. Spritzing your plants for me is just too risky...

[Halloamey]

All my orchids are only given foliar feed once a week (I have foliar fertilized (150 ppm each of NPK 3 times a week with good results, but now it is impossible for my mother who currently takes care of my ~ 1000 orchids and other plants to spend so much time on them every other day). They might also get the fertilizer drip off to the roots. As far as the science goes, it has been proven with many experiments like, radio isotope tagging etc. here are a few old articles that I found on the web that appear in the Orchid Society of Southwest Asia journal and some other books. A few years back there was an article in the AOS magazine, with research by MSU department of Horticulture, can't find it online though.

Do Orchids take in food only through their Roots???

The following article, on foliar feeding was extracted from The Arizona Orchidist Newsletter, Feb ’71, which took it from the Orchid Digest, Jan-Feb ’71, “Orchid Leaves, by Yeoh Bok Choon, which took it from the Orchid Society of Southwest Asia Bulletin, July ’70.]

Many view the idea of foliar feeding, [apply fertilizer, e.g. spray, onto leaves of a plant], with great scepticism and frank disbelief. But the use of radio-active isotopes of Potassium and the tracking of their migration from leaves to stem to roots and back again, have proved beyond doubt that foliar absorption is a fact and not a wild theory.Foliar absorption is also much more efficient than root absorption. It has been estimated that if chemicals are fed to the roots, 10 percent is absorbed and 90 percent is wasted or held in the soil. In foliar feeding, 90 percent is absorbed and only 10 percent is wasted. The efficiency of foliar absorption is very clear. The orchid has not suddenly changed its habits but has been doing this ever since the beginning of plant life; only, until now, we had not the means to discover the process.The top of the orchid leaf is thicker than the bottom side and is covered with a slightly waxy layer. This allows water to run off the upper layer of the leaf more easily and displeases the foliar feeder who would like the chemicals to stay longer on the top of the leaf. Adding a wetting agent or a detergent to the chemicals is thus done to help overcome the wax barrier.The underside of the orchid leaf, being the thinner and lacking the waxy layer, absorbs water and chemicals much more quickly than the upper. So that is where one should spray the chemicals for foliar feeding, [as well as for pesky bugs hiding underneath!!]

Is the aforementioned information out-of-date and now incorrect? No!! The following information, section B, C; D, shows paraphrased excerpts from various publications during the 80's and on thru 1994, which further substantiate the fertilizing technique as legitimate.]

The following paraphrased excerpts were compiled by Robert M. Hamilton, Richmond, B.C.,Canada, and published in 1988, in the THE NEW ORCHID DOCTOR, page 34,35.



"...experiments show that 90% of the total potential absorption capable into an orchid leaf occurs within 30 seconds if the leaf is moist." Orchid Advocate, page 80, 1980. "cattleya leaf intake can be vividly demonstrated with radioactive phosphate moving into the leaf, then to the pseudobulb." AOS BULLETIN, 1985, page 974.

More proof: experiments showed that a cattleya hybrid absorbed a trace chemical through the leaves which suggests other nutrients will also be absorbed; mid morning is the best time to apply." AUSTRALIAN ORCHID REVIEW, 1982, page 107; AOS BULLETIN 1984, p.210 and 1986, p. 719.

More proof: cattleya leaves and roots absorbed derivatives from phosphoric acid; absorption thru the leaves was transmitted to the pseudobulbs within 24 hours." ORCHID BIOLOGY, Vol. II, 1982, p. 209.

[cdayinflorida]

I believe in foliar feeding. I spray mine in the very, very early morning when the leaves' stoma are still open. Some say this has no bearing if the stomata is open or not. I just know it works for me. And I still believe that my plants benefit greatly from spraying the leaves and roots with seaweed extract.

[cakedaddy]

I do a foliar spray as well when I fertilize. I also mist heavily if it is very hot and arid out, but my plants are outdoors for the summer and they get lots of breeze. I do make it a point to make a complete fool of myself if I am not off my day job in time for the chids to have a few hours to dry off before bed!
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[mujacko2002]

Mabuhay!

Since most of my orchids are attached to the trees in the garden i make sure that the whole plant is sprayed including the branch it is on since the roots are everywhere. And my trees, i guess, gets some too.

[Jef09071984]

I also do the Foliar feeding, since my orchids are outside the house and no harm done with this technique.

[Tom-19951]

I grow plants inside and outside...Foliar feeding is very efficient IMO. I do root feeding for plants in pot but I also do foliar feeding from time to time. For mounted plants, I mostly do foliar feeding(the roots also get some from the spray). For example, I spray my plants with epsom salt(1 tsp per galon of water), by the end of the day, I can see my plants are much much greener.

Give it a test, it is not going to hurt your plants...

[catttan]

I've been using foliar feeding for more than 40 years since the late 60s. Amey has given some very pertinent facts re forliar feeding. In the 60s there was a lot of scepticism regarding this ,until as mentioned by Amey, tests were made with radio isotopes. It is also very interesting to note that Amey mentioned Yeoh Bok Choon. The late Dr Yeoh Bok Choon was one of the pioneers of orchid growing in what was then Malaya (now Malaysia). He was for many years the President of the Malayan Orchid Society ( predecessor of the present Orchid Society of Southeast Asia OSSEA - organiser of 20th WOC) and long time editor of the Malayan Orchid Review. A prominent physician, he brought with him his scientific training and expertise into orchid breeding and growing. He was honoured by the orchid community by having a multi genera named after him Bokchoonara (Bkch) = Arachnis x Ascocentrum x Paraphalaenopsis x Vanda . He was acknowledged as an authority in all things orchids. As a contemporary of my uncle, they were very good friends and I shall always remember the discussions and arguments they had regarding orchids and their nomenclature. Both came from a generation where the study of Latin was compulsory and I still remember the letters they exchanged regarding the Genus 'Aerides' whether it should be singular or plural and thus Aer odoratum or ordorata, multiflorum or multiflora etc.

[opaline]

I am a firm believer in foliar feeding aswell as tonic and hormone treatment (when required). I never apply direct to media/root ball. Upper and under sides of leaves twice daily heavily. This allows for run off giving the plant chance to absorb and reduce build up of deposits exposing roots to toxicity. Many of my orchids over the past have encountered near death experiences from rot and if it werent for foliar intake I very much doubt their survival.

To support this also is the action of enclosing sick rootless orchid in a micro climate such as pop bottle, terrarium or sphag bag to maintain high humidity. Left in situ the plant would dehydrate and once the leaves and PB shrivel its pretty much past the point of no return. For the duration of its hospital treatment I have observed a much greater probability of the plant remaining stable and hydrated - so if there are no roots and a cell damaged base how does it stay hydrated.? This is my opinion obviously and is subject to debate but nothing would change my mind , I believe what my eyes see. And that goes for seaweed extract aswell!