Since 1950, liquid fertilizers have enjoyed a newfound and steadily increasing popularity among home gardeners.
This enthusiasm spotlights the power of modern advertising, for, lacking the impetus of the latter, commercial growers were much slower to accept liquid fertilizer for use on their greenhouse crops.
Because of the effectiveness and labor-saving features of applying nutrients and water in one operation, this writer recommended the practice to commercial growers for 10 years before the idea was generally accepted in commercial greenhouses in 1948.
It is interesting to note, also, that the popularity of liquid fertilizers has been sustained among home gardeners despite unwarranted advertising claims.
Let’s see why gardening enthusiasts have adopted liquid fertilizers.
Little Risk Of Injuring Plants
First, there is little risk of injuring plants when liquid fertilizers are used, even roughly per the manufacturer’s directions.
In contrast with this, it is common for the amateur gardener to use regular dry fertilizer in excessive amounts that are harmful or even lethal to some plants.
Secondly, small amounts of fertilizer applied with water are extremely effective in stimulating plant growth on a wide variety of soils.
In this respect, due credit must be given to the water, for it comprises 90% percent of the fresh weight of most of our herbaceous plants, and often, no doubt, garden plants need water as much as they need fertilizer.
Effective In Transporting Nutrients
Moreover, water is most effective in transporting nutrients through the soil to plant roots.
Finally, a gardener can conveniently apply liquid fertilizer over rough ground or smooth, and he can do it accurately.
Liquid plant foods, then, offer numerous advantages over conventional dry materials.
However, present-day methods of applying the liquids can be cited as a disadvantage and an advantage.
It’s true that where relatively small lawn and garden areas are involved, and assuming that watering has to be done anyway.
Simplifies Plant Feeding
The soluble fertilizers simplify plant feeding. But this is not the case where the area to be fertilized is large.
In fact, it takes so long to apply liquid fertilizer in effective amounts to large areas that fertilizing can still be done much more quickly with dry materials and a small distributor.
The reason is that present applicators are not designed for large-scale liquid feeding.
What we need is a device that will dispense a concentrated liquid fertilizer, or a soluble fertilizer, uniformly through a garden hose without reducing the full flow of water significantly.
However, the recent appearance of larger applicators suggests that inventors have noticed this need!
Preparation Of Liquid Fertilizer
Liquid fertilizers can be prepared from regular dry fertilizers, manures, concentrated liquid fertilizers, or specially prepared soluble fertilizers.
The common dry fertilizers dissolve slowly and incompletely; hence they are not conveniently used to prepare liquid fertilizer.
The preparation of liquid manures is time-consuming, messy, and wasteful.
Costs Of Liquid Fertilizer
Concentrated liquid fertilizers are usually expensive due largely to the cost of packaging and shipping a large amount of water involved.
Good Soluble Fertilizer
Soluble fertilizers, on the other hand, are made expressly for the preparation of liquid fertilizer.
They may include as many or as few plant nutrients as the manufacturer wants to put in them.
A good soluble fertilizer, therefore, may contain the same nutrients as any other good fertilizer and may be equal in all respects to the latter in stimulating plant growth.
As for comparative cost, an excellent soluble fertilizer needs to cost a little more, per unit of nutrient, than a high-grade dry one.
Soluble fertilizers, even those of the same grade, are not all alike. Different brands vary considerably in composition.
Some contain many more plant nutrients than others — especially the “trace” nutrients.
Soluble Fertilizers With Fewer Nutrient Elements
In general, soluble fertilizers with the highest guaranteed analyses tend to contain the fewest nutrient elements.
In most cases, this is necessitated by the number of ingredients used per pound of fertilizer to ensure the guaranteed analyses leave little or no room for other nutrients.
The highest guaranteed analysis, therefore, does not usually represent the best fertilizer.
Essential Nutrients For Garden Soils
Garden soils are far more variable than farmland. In many instances, the former is made from subdivisions of land that are submarginal for agricultural use.
Very often, a garden area has been developed from the fill material. Because of this, fertilizer recommendations for garden soils must be based on broad generalizations.
This is justified in that we know that all plants require some 15 different nutrient elements.
Of these elements, carbon comprises about 40% percent of the dry weight of plants and is supplied by the carbon dioxide in the air.
Hydrogen and oxygen together make up another 45% to 50% percent of the dry weight of plants.
The remaining 10% to 15% percent is comprised of the following:
- Nitrogen
- Phosphorus
- Potassium
- Calcium
- Magnesium
- Sulfur
- Iron
- Manganese
- Boron
- Zinc
- Copper
- Molybdenum
Some cobalt is present in plants and is necessary to support animal life. Recent work at the University of California indicates that cobalt may also be essential to plant growth.
Sodium also is found in small amounts in plants. This element is also essential for animal life, but an arbitrary definition of essentiality for plants places this element on the questionable list.
Elements In The Ash Of Plants
Work with beet crops has shown marked growth stimulation following applications of sodium salts.
Many elements in the ash of plants have not been found necessary for their growth.
Some of these, however, may perform useful functions. Silicon, for example, is widely distributed in plants, although it does not appear to be essential.
In some grasses, silicon is thought to stiffen stems and help keep the plant upright.
Useful Function Of Aluminum
Finally, aluminum is found in small to liberal amounts in plants, although a large amount might sometimes prove toxic.
In hydrangeas, aluminum performs a useful function since this element is necessary for the formation of the blue pigment in the flowers of blue hydrangeas.
Siphoning devices mix a concentrated solution contained in a pail or other receptacle with the water that passes through the hose.
It can be attached either at the faucet (above) or at the end of the hose (right). Application is by nozzle, sprinkler, or soaker.
Foliar Feeding
- Cucumber seedlings were grown in good potting soil: left, check; right, foliar fed with liquid plant food.
- Larger, more elaborate applicators, as at left, hold up to 10 pounds of material.
- It will treat areas up to 20,000 square feet with a root-feeding attachment. Above, soluble fertilizers can be used for supplying nutrients to deep-rooted trees and shrubs.
Root Feeding
- Coleus plants grown in average garden soil: left, root fed with a complete plant food solution; right, check.
Trace Elements
- Liquid fertilizers containing all nutrients prevent abnormalities, as in the boron-deficient tomatoes above.
44659 by O. Wesley Davidson