Foliar feeding

[John Case]

A month ago, I rigged up an irrigation system that uses the water directly from my Koi pond bead filter through the sump area, which get a small amount of the dead bacteria and other detritus as well as the water. The first smell I get is pretty 'fresh', but after a couple of minutes I am only watering from the pond water.

The palm here get this water all over themselves, leaves, ground, trunk, whatever. In other discussions (not on this forum) the benefits of 'foliar feeding' have been tossed around for some time.

The initial results of this watering have pretty pretty amazing and I would expect a greening of the plants but it has exceeded my expectations.

Now, I realize that this is ther best time of the year for growing palms and we have had some pretty fair weather as well, but the green and growth has been phenomenal. Even my Flamethrower looks like it may complete a new lef this year before the fall ends!

Looking for informed opinions on the subject of foliar feeding, even though I am not much of an adherent, I may be changing my mind.

[AggiePalms]

I can say that foliar fertilization definitely helps my palms. My primary fertilizer is my mix of organic composts. However, foliar spray makes a great addition. I use a hydrolized fish fertilizer, importantly with a proprietary "micronutrient" product. One spray every month or so. I gave it a test to see if it mattered: One half of the yard got foliar feeding last month, the other half did not. Dozens of species in each half. The side with the foliar spray with "micronutrients" has grown much quicker. All the plants are growing quickly this time of year; the sprayed plants are doing even better. Foliar feeding: It stinks; it works!

[kahili]

There are pros and cons to foliar (liquid) feeding. I think the foremost is that you can have better control of your fertilization through foliar and can make adjustments the quickest (nutrients, PH) etc. Actually,I think thats about the biggest pro (although a very large one). Foliar is just another way to get fertilizer to the roots of a plant-the leaves are secondary. In other words, someone who only fertilizes the leaves of a plant (with no slow release fert used) and not the soil is going to have a very underfertilized plant! When I foliar feed, I drench the soil. If the plant is small enough to be under the stream of water, then it gets wer, if it doesn't, I don't really care. Having said that, the majority of what I foliar feed are small plants that do get wet.

As a commercial grower of annuals that are grown in small containers and grow quickly, its the only way that I fertilize them, but with my tropical plants and palms in containers, and any plants in the ground, I always use a good slow release fert with micro-nutrients. Its fast, easy and as long as they get water-the fert releases and all of my plants look fine and are growing. There is no way that I would take the time to foliar feed if I didn't have to.

If you are talking about only using organic fertilizing-then that is a component of foliar fertilizing that I can't talk about! I could never grow annuals commercially with a organic program, and because of our cold winters, there is too short a growing time for the plants in the ground to use such low numbers and get any real growth.

[ariscott]

They are great for really sensitive species like the ones from Borneo. I have been told that it was too easy to over fertilise them. So, I use foliar feeding for those, especially as seedlings. It takes a lot of my time though

Regards, Ari

[John Case]

I am especially curious lof the uptake mechanism as the only way foliar feeding can work, I think, is through the leaf stomatas.......unless someone has other and better information. My understanding was that stomata are orgnaelles that only deal with gasses, such as water vapor and CO2 and O2 transport....

Is there any hard science I can look at? I am truly curious, more now than ever.

[Moose]

John - I have addressed this with the "in the know" Florida Palm nutritional gurus. Their position is that the leaves take up 1 1/2 to 2 % of the foliar feed. The roots absorb the nutrients at a much better rate. I am a firm believer in granular slow release fertilizer and splashing the leaves with "liquid love" during the growing season. Good results as you have described.

This method can really accelerate weed production which is a major draw back.

Ron.

[John Case]

John - I have addressed this with the "in the know" Florida Palm nutritional gurus. Their position is that the leaves take up 1 1/2 to 2 % of the foliar feed. The roots absorb the nutrients at a much better rate. I am a firm believer in granular slow release fertilizer and splashing the leaves with "liquid love" during the growing season. Good results as you have described.

This method can really accelerate weed production which is a major draw back.

Ron.

I'm trying to ignore the flush of weeds that will come......

[kahili]

This is really basic "fertilizer 101" that plants take up the vast majority of food through the roots, so it should be very easy for you to verify through Google or some other search engine. Stick to .edu sites and I think you will feel better about the info that you get there.

Also consider that stomata are only open during warm periods of the day, so if you fertilize early in the day before they are open, they will not take it in.

ariscott-I also foliar feed my palm seedlings that are in containers smaller than one gallon containers, but I actually think it is easier to burn a plant through foliar feeding than slow release. Many people don't realize that foliar fertilizer is measured in ppm and that it must be weighed in order to have it be accurate. Hence, it is very easy to have your ppm be too high, and then burn the roots. Imo, its a lot easier to remove some slow release granules from the top (or replace the soil if mixed in) then to leach out the liquid fert after it has burned the roots.

[ariscott]

I have to be careful with slow release as I live in hot tropical climates. Some will dump way too much fertilisers when it is hot - which is all the time during the growing season. So, for really sensitive species, seasol is the only way I fertilise. I guess for colder climates, you don't have that problem. I usually do little and often with the seasol, although not as often as I would like...

Regards, Ari

[kahili]

I think Osmocote had that reputation of uncontrolled release due to hot temps, but there are others that don't do it. We have at least 5-6 months where the the temps are in the 90's -100 degrees ( in the 30's C) and I use Multicote because it does release at an even rate in those high temps. I read a little about Seasol, it said that there is no nitrogen or phosphorus in it. Do you use something else with it?

[ariscott]

Yes... I use multicote too... less accidents so far. I don't use anything else on my seedlings... I lost a few licuala & other Borneo species due to over fertilising, so I don't risk it anymore. They just grow a bit slower... but then once they are big enough, I can start putting multicote on them.

Regards, Ari

[sonoranfans]

I have seen real differences in the arizona desert, not so much in florida so far. It probably depends on species, surface conditions, and on what nutrients are actually being applied/absorbed. I read somewhere that iron sulfate is best used in a foliar application, but other forms of iron work better around the roots. Not sure why this is but Iron sulfate gives a somewhat acidic solition in water, but if you add that to neutral soil, the iron bioavailibility drops(Iron prefers a pH lower than 6.5 for best availability unless its chelated). It could be that dry foliage absorbs better than wet as well, I have seen dry looking foilage really plump up with a foliar water application(yes, after drying) in the desert. I suspect the mechanism is driven by entropy(equilibration of concentration gradients), and also by cell functions. If your fertilizer/nutrient solution is dilluted by condensate(due) the concentration gradient drops, hence the osmotic driving force will drop. I suspect large molecules will have great difficulty penetrating plant membranes while small entities(like iron) will penetrate much better.