foliar spray questions

[the undertaker]

hi, i have a few questions about foliar feeding your plants.

i am planning on giving my small plants/sprouts (2 sets of leaves each) a foliar feed of seaweed/kelp because of the growth enhancer that is in it (forgot the name)

the brand of liquid seaweed i have is grandma enggy's and i believe it is made by advanced nutrients but im not 100% on that because i havent looked at it in a little bit.

how much should i mix up, and how should i go about doing this? i heard that i should just spray, spray, spray on the plants and let them sit out from under the lights for about 30mins so they can absorb, then take a paper towel and dry them and they are good to go.

is this correct?

if not, can you please give me instructions on how to do it the proper way?

 

[vonforne]

Quote:
Table of Contents

* Introduction
* Background
* Foliar Fertilization and Pest Resistance
* The Basics of Foliar Feeding
* Further Application Technologies
* Formulating Foliar Sprays
* Component Fertilizers for Foliar Fertilization
* Crop Manipulation through Foliar Fertilization

Foliar fertilization (or foliar feeding) entails the application—via spraying—of nutrients to plant leaves and stems and their absorption at those sites. Used in both conventional and alternative production systems, it is a viable (though somewhat controversial) means of enhancing crop nutrition. Because information on conventional applications of foliar feeding is usually available through Cooperative Extension and the general farm press, this publication will stress applications in sustainable and organic agricultural systems. For more detail on what is meant by sustainable and organic agriculture, see ATTRA's Sustainable Agriculture: An Introduction and Organic Crop Production Overview.

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Background

Foliar feeding has been used as a means of supplying supplemental doses of minor and major nutrients, plant hormones, stimulants, and other beneficial substances. Observed effects of foliar fertilization have included yield increases, resistance to diseases and insect pests, improved drought tolerance, and enhanced crop quality. Plant response is dependent on species, fertilizer form, concentration, and frequency of application, as well as the stage of plant growth.

Foliar applications are often timed to coincide with specific vegetative or fruiting stages of growth, and the fertilizer formula is adjusted accordingly. Applications may also be used to aid plants in recovery from transplant shock, hail damage, or the results of other weather extremes.

In terms of nutrient absorption, foliar fertilization can be from 8 to 20 times as efficient as ground application. (1) However, this efficiency is not always achieved in actual practice. Often, failures result from inattention to the principles of foliar feeding. (see The Basics of Foliar Feeding below) Other causes of failure include application of the wrong spray mix, or of the right mix at the wrong time. Judging what foliar materials to apply and at what plant stage to spray them appears to be as much art as science.

Because of the variability in research results and practical field experience with foliar feeding, opinions on its usefulness vary in both conventional and alternative agriculture circles. There is general consensus, however, that foliar fertilization should not be considered a substitute for a sound soil-fertility program. For operations seeking to farm more sustainably, this includes some combination of compost, livestock manure, green manure, cover crops, soil-applied rock minerals, and well-planned crop rotations that include legumes.

One of the touted benefits of foliar fertilization is the increased uptake of nutrients from the soil. This notion is based on the belief that foliar fertilization causes the plant to pump more sugars and other exudates from its roots into the rhizosphere. Beneficial microbial populations in the root zone are stimulated by the increased availability of these exudates. In turn, this enhanced biological activity increases the availability of nutrients, disease-suppressive biochemicals, vitamins, and other factors beneficial to the plant. It is this rationale, in good part, that reinforces the use of foliar fertilization in organic agriculture, where the philosophy of feed the soil, not the plant prevails.

While foliar fertilization is being used on a wide variety of crops, its economic value is generally deemed greater for horticultural than for agronomic crops. This is because horticultural crops are of higher value and their nutrient status is more carefully monitored. At present, for example, foliar sprays are commonly recommended to correct zinc deficiencies in grapes (2), to control bitter pit and cork spot in apples (3), and for general supplementary nutrition in strawberries. (4)

Overall, the economics of foliar fertilization is dependent, first, on how successful applications are and, second, on whether or not the same nutrition might have been supplied more economically through another means. Because weather can be a factor and because circumstances differ widely among farms and farm managers, there is no simple determination. The individual grower must decide based on need, and monitor for indicators of success.

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Foliar Fertilization and Pest Resistance

It is a basic tenet of organic agriculture that properly nourished crops will exhibit a natural resistance to insect pests and disease organisms. While traditionally most practitioners try to achieve optimum nutrition through direct soil management, many consider foliar fertilization the final key to making some form of "induced resistance" a practical reality.

There are several schools of thought regarding pest resistance and crop nutrition. Some suggest that well-nourished plants certainly have a better ability to tolerate pests and disease, but that there is no induced resistance; others deny any relationship at all between crop nutrition and the incidence of pests.

Some connections between pest problems and nutrient imbalances are documented. The presence of excessive soluble nitrogen in soils, for example, increases the nitrate and water content of plant cells. This is especially attractive to aphids, which thrive on plant sap. (5)
Among the more popular theories is that plant sap with a higher level of soluble solids—measured as °Brix—is unsuitable food for plant-eating insects. Research on this theory is limited and far from conclusive. One California study, for example, failed to find a relationship between the °Brix of sap in commercial grape plantings and the presence of leafhoppers. (6) See the section Formulating Foliar Sprays for details on how foliar feeding is used to increase soluble solids in plant sap.

Some proponents of foliar fertilization consider it an especially effective means of stimulating the natural defense mechanisms of plants. Studies to date are rather limited but have shown some positive results. Israeli research on corn using foliar sprays of phosphate and of trace nutrients demonstrated induced resistance to several diseases. (7)

For a good overview of the research and theory relating pest infestations to fertility, Gary Zimmer's Crop Pests and Fertilizers—Is There a Connection? is recommended. (8)

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The Basics of Foliar Feeding

For foliar fertilization to work effectively, certain guidelines must be followed:

* To be efficient and to avoid crop damage, very dilute solutions of nutrient formulations are suggested. Sometimes as little as one cup to two quarts per acre of an active ingredient is all that is required to obtain the desired response. (1) Highly concentrated sprays, especially those bearing inorganic salt-based fertilizers, have the potential to "burn" plant foliage. This is especially true of chloride salts (e.g., potassium chloride).
* Spray-solution pH should remain in the near-neutral range (5.5-8.5). If pH adjustment is required, vinegar can be used to increase acidity, and baking soda to decrease it.
* In addition to pH, some other qualities of spray-water should be considered:
o Cleanliness. Small, undissolved particles can quickly clog nozzles—even those well-equipped with strainers can be plugged if enough suspended matter is present.
o Chemical and disease contaminants. Some water sources are contaminated and should not be used at all for foliar feeding. If there is concern specifically about disease organisms, the water can be treated effectively with a small amount of hydrogen peroxide.
o Chlorine. Chlorination of water removes harmful bacteria, but it also can kill beneficial organisms, which may be included in some foliar sprays. Allowing water to stand in an open tank overnight generally renders chlorinated water harmless to beneficial microbial mixtures.
* Best effect is achieved when foliar sprays are finely atomized. This can be managed by increasing sprayer pressure or by using a mist blower. Some advantage can be gained on boom-type sprayers by tilting the nozzles back to a 45° angle to allow the spray to drift onto the plants.
* Spray when wind is minimal. This is especially important with finely atomized sprays because they drift readily.
* Absorption is increased when sprays also reach and coat the undersides of leaves. This is where most of the plant's stomates are located.
* Always delay foliar fertilization until air temperatures drop to 80°F or below. Absorption at higher temperatures is very poor because plant stomates are closed. Some of the most effective foliar feeding is done late in the evening or in the early dawn, when temperatures are right and wind is minimal.
* Absorption is further enhanced when weather conditions are humid and moist. The presence of heavy dew on the leaves facilitates foliar feeding.
* Addition of a surfactant to the solution decreases surface tension on the leaf and may increase absorption.
* Take note of possible chemical interactions among foliar fertilizers. Some materials are incompatible and should not be mixed together. They may create precipitates that tie up the nutrients and clog nozzles. Many product labels warn of incompatibilities. If there is no information, mix relative quantities of the materials and water in a jar and shake it. If there is no precipitate, there should be no problem.
* For convenience and cost savings, foliar fertilization can sometimes be combined with a pesticide application. However, timing conflicts and material incompatibilities can make combining sprays unwise. Be certain to read all product labels and do the jar test if uncertain.

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Further Application Technologies

Two technologies that appear especially applicable to foliar fertilization deserve to be mentioned. The first is the use of electrostatic sprayers, which impart a charge to the spray particles and cause them to adhere more readily to plants. The second technology, known as Sonic Bloom™, uses sound to increase the leaves' absorption of nutrients. For more information on electrostatic sprayers, contact the manufacturers (such as Electrostatic Spraying Systems Inc. at 706-769-0025). For more information on Sonic Bloom, contact ATTRA.

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Formulating Foliar Sprays

Unfortunately, foliar fertilization is often attempted without clear objectives. Sometimes the grower has been convinced—perhaps by a salesperson—that spraying a particular product will be good for the crop. Sometimes it is simply a matter of faith.

Foliar fertilization need not be undertaken in such a haphazard manner. There are several methods for determining need, possible benefits, and what materials to apply. These methods range from conventional analytical approaches to some that are best described as metaphysical. The most common farmer-friendly approaches are discussed here.

Deficiency History or Symptoms
In areas where crop production has continued for some time and where the interactions of particular crops and soils have been well studied, certain nutrient deficiencies are predictable. Where these deficiencies involve secondary nutrients and micronutrients, foliar feeding often becomes the preferred means of correction. For example, foliar feeding is routinely used in some regions to manage zinc deficiencies on pecan crops. Likewise, calcium sprays have often been recommended as one means to prevent blossom-end rot in tomatoes. The decision to spray in such cases is basically the result of past experience, often bolstered with soil test information and/or observation of symptoms in the field.

Plant Tissue Tests
Tissue nutrient tests are much more reliable than past history, plant symptoms, or soil tests for establishing whether nutrient deficiencies exist. They can, however, work hand-in-hand with any or all of these. In most high-value horticultural crops on large acreage (commercial pecans and tomatoes included), tissue testing is routine. This is perhaps the most commonly accepted means of identifying nutrient deficiencies. The suitability of foliar feeding as a corrective agent usually depends on the deficient nutrient. For example, it is more common to use foliar feeding if a micronutrient is needed than if nitrogen, phosphate, or potash are deficient.

Many soil testing services also offer tissue testing. The same is true of many state-run laboratories. The University of Arkansas, for example, has a program specializing in the foliar analysis of blueberries—a crop of significant value in the state. ATTRA's Alternative Soil Testing Laboratories publication lists a large number of independent testing facilities, many of which also provide tissue analysis services.

Be aware that accurate foliar analysis depends on good sampling and handling procedures. While instructions should be obtained from each laboratory or consulting service in advance, some good general advice is provided in the enclosure entitled Leaf/Petiole (Stem) Sampling.

Refractometers
An instrument that some growers find useful in combination with foliar feeding is the refractometer. Refractometers are low-cost hand-held tools that measure the dissolved solids (mostly sugars) in plant sap, by observing the bending (refraction) of light as it passes through the liquid. The higher the percentage of dissolved solids present, the better nourished the plant. As indicated earlier, many proponents of foliar fertilization associate higher °Brix readings with pest resistance.

The process for using the refractometer to guide foliar feeding is relatively simple. Begin by extracting a sample of sap from one or more crop plants. This is accomplished by squeezing the leaves or stems with a garlic press or some other tool. Place the extracted sap in the refractometer to measure and record the reading. Then, use a spray bottle to mist a small sample of a foliar spray blend onto the plants. After a short time, extract and measure another sap sample. If the °Brix has increased, foliar feeding with that specific blend is advisable. By testing several possible blends using several spray bottles, you can determine the best spray to use. Of course, a control spray of water should be tested at the same time to discount any changes not caused by the fertilizer.

Use of the refractometer in this manner is common among proponents of Reams Biologic Ionization Theory, as well as others within the alternative agriculture movement. It is not, however, a widely accepted practice nor, as indicated earlier, is it especially well-researched as yet. For more information on refractometers and their use for foliar feeding and crop management, chapters 14 and 15 in The Non-Toxic Farming Handbook by Wheeler and Ward (9), are recommended, as are chapter 16 and appendices 1 and 3 in Andersen's Science In Agriculture. (10) A good online resource is Using a Refractometer to Test the Quality of Fruits and Vegetables. (11) Note: also that some promotional literature from Agri-Mart is included, which provides a drawing of a refractometer and the refractive indices (°Brix) recommended for specific crops. Also enclosed is a brief article by Gary Zimmer entitled, Can Health be Measured?

Radionic/Radiesthetic Analysis
Radionics and radiesthesia (dowsing) are metaphysical approaches to determining the need for foliar fertilization and formulating the fertilizer sprays to be used. Despite the pseudoscientific nature of these modalities, they apparently are used with significant success by a surprising number of farmers. This writer had exceptional results using radionics to guide foliar feeding of commercial blueberries and blackberries in the late 1980s. For more general information on this subject see chapter 6 in The Non-Toxic Farming Handbook (9), and chapter 22 in Science In Agriculture. (10) (The authors use the term "electronic scanner" to describe a radionic device.) For how-to information on using radionics for plant culture, the book Plants, Soils, Earth Energy & Radionics is recommended. (12)

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Component Fertilizers for Foliar Fertilization

Synthetic Fertilizers
Most soluble conventional fertilizer materials can be used for foliar fertilization. Hot mix liquid and dry soluble formulations (e.g., Miracle-Gro™ products) are usually preferred, as they are designed to be dissolved in water and contain few contaminants. Fertilizers containing significant amounts of chlorine, however, should be avoided to reduce the chances of plant damage. Note that synthetic fertilizer materials are not permitted in organic production.

Organic Fertilizers
Fish-based fertilizers (fish emulsion or fish powder) and seaweed (soluble seaweed powder or seaweed extract) are among the most common foliar feeds in organic farming, applied either separately or in combination. Information on these fertilizers is available, as both have been in general use for many decades. The Non-Toxic Farming Handbook (9) provides information on using fish-based fertilizers for both foliar and soil applications. Various books by Lee Fryer, such as The Bio-Gardener's Bible (13), are also good sources of advice on the use of fish fertilizers. Details and references on kelp as a fertilizer are available from ATTRA.

Compost tea has become popular as a foliar spray material because of its nutrient content and disease-suppressive characteristics. For further information on the production of compost teas, Compost Tea Manual by Ingham is suggested. (14) Also see the ATTRA publication Notes on Compost Teas.

Other soluble organic materials and those from which extracts are easily made include spray-dried blood, bat guano, worm castings, manure teas, humates, molasses, milk, B vitamins, and herbal extracts of plants like stinging nettle and horsetail. Several enclosures are provided that give further detail on these and other organic foliar fertilizer components. Take particular note of Cantisano's "What to use for foliar feeding," a very enlightening and informative article that contains specific product references and commonly recommended rates.

Additional articles on homemade foliar fertilizers also are enclosed, with particular emphasis on teas made from weeds. Information on this subject matter is often difficult to find. Some of it, the reader will note, comes from the Biodynamic™ school—a metaphysics-based approach to organics. ATTRA's publication Biodynamic Farming & Compost Preparation is recommended for further reading on this subject.

Foliar Fertilization for Organic Farming
Organic growers should be cautious when purchasing commercial foliar feeding products. Not all are cleared for certified production. Some have been blended with conventional fertilizer materials. Certain stimulants, biocatalysts, and other materials are also prohibited, often because they contain or are derived from genetically engineered organisms.

Organic producers must be cautious when using manure- or guano-based teas. Federal regulations limit the time between application and harvest of food crops. Compost teas, from compost produced according to USDA requirements, may or may not be restricted in the same way. It is important to consult your certifier in advance. For further information, see ATTRA's Manures for Organic Crop Production.

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Crop Manipulation through Foliar Fertilization

Fertilization strategies can influence flowering, fruit set, fruit size, the amount of vegetative growth, and other plant characteristics. By carefully choosing the components of a foliar or sidedress fertilizer, the grower can "nudge" a crop toward earlier, heavier fruit set, or discourage fruiting—an advantage when producing greens or a forage crop. This concept is fairly well recognized in the conventional agricultural community. Many citrus growers, for example, are known to foliar feed with fertilizer blends dominated by potassium and nitrate—vegetative-growth-enhancing nutrients—to increase fruit size after the crop is well set. Generally speaking, fertilizer blends dominated by potassium, nitrate nitrogen, calcium, and chlorine tend to promote vegetative growth and fruit size. Blends dominated by ammonium nitrogen, phosphorus, sulfur, and manganese encourage the setting of fruit and seed.

While this knowledge gives the farmer more management options, one should not assume too much when trying to manipulate crop performance. All crops—but especially fruit crops—will need certain amounts of both growth- and fruit-enhancing nutrients throughout the season. Imprecise timing, or attempts to tip the balance too far, can yield disappointing and costly results. Note, too, that these manipulations can be especially difficult for certified organic producers to attempt with the smaller array of soluble fertilizer materials available for their use.

For more detail on how fertilization can be used to influence crop growth in this manner, chapter 13 in The Non-Toxic Farm Handbook (9), and chapter 11 in Science In Agriculture (10), are recommended. The authors of both these texts are heavily influenced by Cary Reams's Biological Ionization Theory. Their explanations might appear confusing at first. Thorough reading of the books may be necessary for a good understanding.

 

[the undertaker]

how much seaweed do i mix into how much water? should i do what the instructions say but cut it by 1/4?

 

[jaykush]

wow thats a grip to read he just wanted an anwer.

hey undertaker you can use that at about 1.4 strength when foliar feeding you want the ratios to be low. spray bottles are so small i never measure just put a little bit in. make sure theres nothing to clog the sprayer. you can also just spray with water the plants love it. and since these are seedlings go real easy on the nutes. i also add vitamin c to seedling foliars crushed up and disolved into the water. then spray.

 

[the undertaker]

jay, why do you use vitamin c?

what is your foliar feeding technique?

 

[jaykush]

just experimenting one day and it seemed to make the plants i used it on a lot greener and healthier than the others i didnt.

i just use a spray bottle and spray lol. not much technique. some say i spray too much but the hell with them

 

[the undertaker]

i added a little fulvic acid to my spray

i read on the bottle it provides some micro nutrients and fights disease and stuff, so i also sprayed a little on my topsoil.

 

[vonforne]

Sorry for the length. You wanted some instructions and no one had answered you....and it was late. Didnt want to leave you with nothing...besides it is a good save for later reference.

I always use my foliar spray at 1/4 strength and I usually only add one component to my foliar at a time. IE....kelp one day, the next time something else. and I always give them a spray of fresh water to keep the leaves clean.

 

[thc43]

i dont know if all sea weed/ kelp extracts work well. on my outdoor plants ive used a cheep kelp extract called seasol it leaves an oily residue so needs to be wash off afterwards.


rhizotonic seems more refined or more soluable and doesnt leave marks or stains, but it does cost about 10x the price and get better effects from using it on the roots..


After playing with folias all last year, from watered down res water with all additives, just nutrient at 1.0ec, and single part grow nutes i found the single part to add the most colour to plants until i tried dutch master foliar range its hard to beat and seem to have abit of science behind all the products.

dutch master range is cheep at some shops and stupidly expensive at other shops, i get it for $15 to 20 per litre or penetrator and folia tech but have seen it sold for upwards of $40 aus at at shop just down the road from the other.

penetrator 60ml per litre delivery agent
folia tech grow or bloom 60ml the folia nute
fx max 60ml adds weight and flavor by increasing brix or sugar content.
some times i add rhizotonic at 4ml but only on clones or first week of veg.

costs me $60 oz for all three bottles could last me atleast 3 grows so its pretty good value, one or two sprays a week is enough any more and you can get pretty close to over fert while root ec is very low.

 

[the undertaker]

thanks for the info guys!

it was very helpful.

 

[quadracer]

I use a Bio Bizz Alg-A-Mic and MetaNaturals 3-3-3 mixture, foliar in the mornings and evenings, and all my plants love life.

 

[PHB]

http://www.icmag.com/ic/showthread.php?t=51314 is an interesting thread on the subject.

 

[the undertaker]

is seaweed and fulvic acid a bad idea? its already a done deal so i want to know if it will harm them... so far it hasnt and they are green and luscious.

 

[vonforne]

If they are green and healthy, you are soing it right...just don't do it to often and keep those leaves clean.

V

 

[the undertaker]

i was planning on giving it to them every few days, and inbetween give them pure water as a foliar so sort of cleanse or whatever... how does this sound?

 

[vonforne]

Perfect. I go one day on,rinse, two days off. Twice a week with kelp (maxi-crop) and or nutes of some kind.

Or if they show a def. a good foliar feeding is just what the doctor ordered.

V

 

[the undertaker]

sounds good!

 

[texas grass]

great read von

 

[moonymonkey]

try waitin until plants need water,foilar spray wait 25 mins. then water ur plants..moon/

 

[jaykush]

foliar spray info

http://www.spraytec.com/9/nutrients-foliar-absorption/

Nutrients - The Mechanism of Foliar Absorption of Nutrients is Not Well Understood

Plants absorb nutrients as well as other chemicals through their foliage to varying degrees. Growers in most all types of agriculture apply foliar nutritional sprays from time to time for various reasons.

A basic philosophy many growers utilize is to apply what is believed to be required to the soil in the fertilization program, and use nutritional foliar supplements as a tool to give crops any nutrients they may still be lacking. Even though growers constantly use this technique as nutritional supplement, the mechanism of foliar absorption of nutrients is not well understood.
foliar absorption of nutrients comes through the leaves
In order to understand foliar absorption, we must first take a look at the surface of a leaf. Moving from the outside. The leaf surface is composed of layers of cuticular wax, followed by the cuticle or "skin" of the leaf. The cuticle exudes the wax. Under the cuticle are the cell walls of various types of leaf cells. Inside the cell walls are the plasma membranes of the cells themselves.

A foliar applied nutrient must pass through the cuticular wax, the cuticle, the cell wall, and the membrane in that order. Sometimes the nutrient will pass through these various layers, while other times it may pass through the spaces between these layers. Such absorption involves both active and passive processes of the leaf.

The second and most often the, major means of foliar absorption is through the stomates, which are microscopic pores in the epidermis of the leaf. When the stomates are open, foliar absorption is often easier. Plant species vary widely in the, number of stomates per leaf area, and in their relative distribution.

Some plants have more stomates on the lower leaf surface than on the upper and some vice versa.

In simpler terms, some plants are, good at absorbing nutrients through their leaves, while others are not. The variables tend to be how many stomates and how they are distributed, and how thick the waxy cuticle of the leaf is.

Plants with large, broad soft leaves such as Spathiphyllum or many bedding plant species are rather efficient at absorbing, foliar nutrients. Palms, Avocados, Cucurbits, some Citrus and Zamias for example are not as adept at this absorption, due to the thicker tougher nature of their foliage.

The speed of absorption of nutrients is quite variable according to the nutrient, and to some degree the plant type. Rates of foliar absorption have generally not been studied in ornamental varieties.

One Thing Not Widely Known is that Nutrients are Generally ONLY ABSORBED while the spray is wet on the Leaf!

Once the spray has dried, absorption generally ceases until the leaves are moistened again, either by the dew the next day or additional rainfall or overhead irrigation. The various types of chelating agents are also not equal in their ability to penetrate the leaf. Some chelating agents work better on some types of plants, but not necessarily as well on others. The best chelating agent will depend in part on what type of plant you are spraying.

Another Common Misconception Regards Rates of Foliar Nutritional Applications.

Generally, there is a great deal of difference between the amount of chemical it takes to maximize absorption and the amount it takes to burn. Absorption is the limiting factor, so don't make your rates too high. You may be able to double or triple the spray rate, but it won't necessary increase absorption. It will increase risk of spray injury, so be conservative in your foliar application rates.

There are a number of situations when foliar nutritional supplements are especially useful. One is during propagation of slow rooting plant material. Long term mist propagation can leach nutrients severely, and foliar nutritional sprays during that time are very helpful. Nutritional sprays can be used efficiently to overcome other problems.

Another useful foliar technique is during cold fronts. When a cold front comes down, frequently you get heavy rain followed by several cold days. During this period, the fertilizer is not releasing a great deal, and the plants are not feeding. That is a good time to come in and apply some foliar nutrition to keep the plants moving until things warm up.

Several Techniques should be Used When Trying to Maximize Foliar Absorption of Nutrients.

One is to try to maximize the time that the spray is wet on the foliage. This preferably means early in the morning, when humidity is up, leaves are wet with dew. Spraying in the middle of a hot day will give you reduced effectiveness in absorption. It also helps to add urea or potassium nitrate to nutritional sprays when applying trace elements.

The mechanism is not known, but there is substantial research that indicates applying these materials with trace, elements increases trace element absorption. Try to spray when the stomates are open, preferably during a cooler time of day. Some industries like to spray at night, and that can be useful in some situations.

Try also to coat both the upper and lower leaf surfaces where practical, as many times the spray stays wet on the leaf longer, and there are more stomates to facilitate absorption on the lower leaf surfaces of many plant varieties.

The use of wetting agents or surfactants also aids in absorption, by spreading out the spray from droplets into a broader shape, increasing contact with the foliage. Surfactants also reduce the angle at which the spray material enters the leaf, which can be useful. It is generally useful to thoroughly wet the foliage when applying nutritional sprays.

Low volume sprayers may not be as effective in some cases. You should spray to run off, and once again cover the lower leaf surfaces.

Finally, do not get too high on your rates. Going higher on the rates of chemicals applied can actually reduce absorption, as can mixing too many nutritionals in the tank at a time.

Foliar nutritional sprays can be a very useful technique, especially when you understand the principles behind it. Nutritional sprays enable you to correct deficiencies, strengthen weak or damaged crops, speed growth and overall grow better plants, which is of course, the bottom line.