Applying Fertilizer – Making Applications Effective

bags of fertilizer

Summary: When applying fertilizer many items must be considered – fertilizer brands, fertilizer prices, liquid, organic, NPK ratio, lawn, vegetables, flower and plants – But the first question is – when you apply fertilizer will it be effective?

Question: We are looking for the best fertilizer for grass, but we also want to fertilize our new garden and the landscape plants.

We have a limited budget and see fertilizer prices from low to very expensive, plus there is organic, liquid, all nitrogen fertilizers and ones made for grass and lawn. Can we just buy one brand and use it on everything. Kaye, Tampa Florida

Answer: Sometimes it is a waste of money and effort to apply fertilizer. Do you know what makes the difference?

If you are going to the trouble of growing roses or vegetables, or any plants for that matter, it’s only sensible to see that they receive a well-balanced diet.

Under certain conditions and in many soils, this is only possible when fertilizers are applied to supplement the food substances already existing in the soil.

But even when we add fertilizers, plants may still starve to death, simply because other factors involved in plant growth have been ignored. Then, feeding your plants is a waste of time and effort.

Before deciding what fertilizers your plants will need and putting in an order for your future wants, let’s quickly check these other factors which may affect plant growth.

Factors Affecting Plant Growth

First, there is the matter of sunshine, for there are very few plants which can exist in a location where direct sunshine doesn’t fall for at least half a day.

Without sun, plants are unable to manufacture food and combine substances taken from the soil into forms they can utilize. Next in consideration is a well-drained soil on which water does not stand after heavy rains.

Most gardeners are only too familiar with the advice to dig their soil deeply, but are sometimes are unwilling to do the job completely. Deep digging, under normal conditions in a humid climate, means inserting the spade or fork to its full depth, 10 to 12 inches.

Such preparation permits easy penetration by all plant roots and free drainage of excess water as well as aeration.

At the time we dig, organic matter should be added to improve the physical and biological properties of the soil. Organic matter is any partly decayed plant or animal residue, which, as it breaks down to become humus, yields for the plants use what chemical elements it contains.

Humus Nature’s Wonder

Humus is truly one of nature’s wonders: in all forms it contributes to the physical condition of the soil.

In heavy soils, it increases drainage of excess water, but in sandy soils it increases the water-holding capacity. In any soil it acts as a buffer against changes in temperature, reserving moisture for dry spells and storing fertilizing elements.

It supplies a source of energy for bacteria and other microorganisms which break down crude matter and make fertilizers available to plants.

Some soils may need lime, best added in the form of agricultural limestone. Soil testing (most state agricultural experiment stations will test your soil) will determine whether it should be added. Many plants, such as rhododenrons and mountain laurel, must have an acid soil.

Still another factor directly involved in the absorption of fertilizers by plants is the presence of ample moisture in the soil to dissolve them.

And finally, when fertilizers are added, they must contain in suitable amounts the three elements, nitrogen, phosphorus and potassium (NPK fertilizer), usually lacking in soluble form.

Any lime applied will supply calcium and magnesium, and minor elements essential to plant growth are usually added by the fertilizer manufacturer.

NPK Fertilizer – Nitrogen, Phosphorus and Potassium

Nitrogen fertilizer, so vital to plant growth, gets to the plants through a number of sources. It can be fixed in the soil or in the nodules (small knobs on the roots) of legumes, returned to the soil by animals in the form of animal manures, manufactured by electro-chemical methods or mined from natural nitrate of soda deposits.

Phosphorus, the second most important element to plant growth, is usually fed to the plants in the form of bonemeal, superphosphate or rock phosphate. The third element is potassium; most gardeners are familiar with muriate of potash. the most popular fertilizer carrying this element.

In most so-called chemical or inorganic fertilizers, the elements are quite readily soluble, hence the plants can take them in as soon as they are dissolved. In organic fertilizers, the compounds are usually very complex and must be oxidized by bacterial action which sometimes takes five or six steps.

Waste Of Money

Sometimes it’s a waste of money and effort to apply fertilizer before the elements become soluble and are then absorbed by the plants.

Fortunately for the home gardener, who has enough to do without carrying on a complicated feeding schedule in his garden, once he is satisfied that growing conditions are as ideal as can be for his plants, supplementary feeding is a fairly simple procedure.

For one thing, one complete fertilizer will serve most plants in the garden.

For instance, in average soil or even in clayey soils, a fertilizer with the formula 5-10-5 (that is, 5 percent nitrogen, 10 percent phosphorus and 5 percent potassium), 7-7-7, 4-12-4 or similar analyisis will be adequate. If the soil is very sandy, especially in regions of heavy rainfall, it is better to have more potassium, as in a 5-10-10 formula.

In applying dry fertilizers, it is advisable to broadcast the material over the surface of the ground and then thoroughly incorporate it in the soil so that there will be food wherever the roots may grow.


When chemical fertilizer is dumped in the planting hole without mixing with the soil before setting the plant, there is danger of too high a concentration which may kill the roots coming in contact with it.

It is even better to broadcast organic fertilizers rather than placing them in the planting hole, as the roots may soon grow beyond this food source. Most of the movement of water in the soil is vertical. Transplanting and starter solutions (liquid fertilizers) are usually so diluted that they will cause no harm.

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