Liquid foliar feeds are used as a quick-fix remedy for specific nutrient shortages.

hat's in contrast to the opinion of many home gardeners who believe it's the preferred fertilization method. Even though the uptake is very efficient, it's not used to sustain the plant as the one & only source of fertilizer elements.

A search w/your favorite search engine should readily locate the why & how.

From the perspective of getting nutrients from outside the plant, inside the plant, foliar feeding is generally extremely inefficient. In those few plants that can/will benefit from foliar feeding, fertilizers in ionic form are far more effective than various emulsions/suspensions at providing supplemental nutrition, but roots are still, by far, the more efficient and reliable pathway for nutrients to enter the plant. Foliar feeding is best suited for use as an intense agri-crop management tool used to compensate for specific soil deficiencies at specific periods of growth. If your plants actually NEED foliar feeding - by default, there is something wrong with your basic nutritional supplementation program or your soil, and your efforts would be better spent concentrating efforts on managing those issues.

Foliar feeding is usually only used effectively to supply a few elements in ionic form (mainly N,Fe,Cu,Mn,Z), and only when plants that are able to provide a foliar pathway into the plant are growing so rapidly the nutrient stream cannot supply certain nutrients fast enough.

Remember - over-supplying a nutrient the plant doesn't need can be as bad as or worse than a deficiency. If you have a genuine deficiency, it's better by far to address it via the most efficient pathway - the root system. You can't make plants grow at beyond their genetic limitations, and supplying more of this or that than plants need is counter-productive. Trying to ensure the 12 elements you have control over are available in the soil at a favorable concentration and in the right ratio is about the best you can do.

I think one area where the hobby grower CAN effectively use foliar feeding is as a 'tell'. That is to say, after your lament and input about a particular symptom, I might suggest a foliar application of some chemical like Epsom salts or ferrous sulfate on part of the plant if I suspected a deficiency of Mg or Fe, for example. Applied one at a time and given a couple of days to work, you might be able to isolate one of several possible deficiencies. Of course, a soil test will usually provide the clues, but absent that, or when growing in containers foliar applications can sometimes be used effectively to tell you what you should be doing in terms of soil nutrition management.

Al

Without going into the deep end about them, liquid fertilizers are the preferred manner to give to food stocks by the farmers of the world and you can read in those forums why it is much more efficient.

There is a difference between foliar feeding and simply applying soluble fertilizers to the soil. Soluble fertilizers applied to the soil end up in the plant through root pathways. I'm not sure that the statement "... liquid fertilizers are the preferred manner to give to food stocks (?) by the farmers of the world ..." can be supported because it is so broad. The best ways to arrive at fertilizing goals are extremely varied, often complex, so to suggest that it's always better or more efficient to supply those fertilizers that are available in soluble form IN soluble form, is probably a leap.

Take care.

Al

Thanks Tapla for taking the time for that, I will get back to you when I have thought about it. And cheers guys for your other responses. Goren, I want it deep end, it is one of those things that solid information is hard to discern with just net searches Jean so I am seeking more understanding.

There are those that think the research that suppoerts leaf (foliar) feeding of plants is flawed and does not support the conclusions reached. If one carefully looks at the often contradictory information about foliar feeding one would have to reach the same conclusion.
I am aware that there are many people that do not think Linda Chalker-Smith has any idea whereof she speaks, but like anyone else she is entitled to speak.

Here is a link that might be useful: Foliar feeding

"The Reality
If these laundry lists look more like a multiple choice test rather than solid information, it's not surprising.
Foliar feeding is yet another agricultural practice best suited to intensive crop production under specific
soil limitations rather than as a landscape management tool. Thus, advertisers take great liberties with the
facts, often resulting in contradictory messages (note especially the recommended temperature
conditions!). Rather than individually refute the numerous errors in the claims, I'll explain when foliar
feeding might actually be beneficial." She then goes on to say, "Generally, the results suggest that foliar application of particular nutrients can be useful in crop production situations where soil conditions limit nutrient availability."

As I read the entirety of what she said, I find it quite similar to what I said, and I take her offering as pretty much pooh poohing the efficacy of the practice for the hobbyist.

Al

btw, that would be Linda Chalker-Scott, not Smith. And she does come with some pretty impressive credentials, even though I don't necessarily agree 100% with everything she advocates. In this case however, she produces some pretty sound evidence that confirms everything Al stated previously.

I know non organic gardeners who use Liquid feed to make their Fall? Winter greens crops "jump" up before the winter sets in.
I am a organic gardener, sshhhh, but I see no reason that this is not okay if done only at the beginning of the season.
I of course, I use compost tea myself.

Sorry to go wide of the topic but I can't say i am a great fan of Linda Chalker-Scott, shh I am into organic growing, she thinks quote "chemical-free and organic are oxymorons". She has missed the point and what she fails to realise, is that organic growing is a philosophy to growing that works with nature, I am not disputing that organics don't use chemicals !!!, everything can be seen in chemical form (well nearly...)