The Importance of Fertilizers

Give your plants the right kind of fertilizer in the right amounts and you’ll be rewarded with beautiful, healthy displays of foliage, fruits and flowers. 

"Is that really necessary?”  A lot of people still don’t appreciate the value of fertilizers. Many tell sorry tales of plants that never flower or leaves that look pale or discolored or plants that are simply too sickly. But if you ask these same garden-lovers if they fertilize their plants, they say, “No. I didn't think it was important.”

If your plants are lucky enough to be growing in superbly rich soil whose organic and nutrient content is constantly replenished by some natural means, then your plants can most likely thrive without fertilizers. But the more common case in our gardens is that plants sooner or later use up what nutrients there are in the soil and therefore will need feeding, which is another way of calling fertilizing. Fertilizers are similar to the vitamin supplements you probably take for yourself. They help fill up shortages in nutrients that plants can’t readily get from the surrounding soil or potting mix. 

Fertilizers come in organic and chemical form. So-called complete fertilizers provide the three major nutrients plants need – nitrogen, phosphorus, and potassium. Nitrogen is necessary for healthy leaf production. Phosphorus promotes overall robustness, from the roots to the stems to the formation of buds. Potassium boosts the quantity, size and longevity of flowers and fruits; it even helps brighten the colors of flower petals. Some fertilizers just provide one or two of these. Other fertilizers provide just micronutrients. While others combine a combination of all these, plus some plant hormones to boot. (The ever popular and over-used Urea is really just nitrogen and nothing more. Although urea occurs naturally in nature as a mineral salt, the popular chemical form used is a very concentrated form of nitrogen, which is why it easily causes fertilizer burn when used improperly. Once again, fertilizers come in both organic and synthetic forms, even the specialized kind. For instance, dried animal blood is actually a very rich natural source of nitrogen for plants.)

So if you still think that plants can thrive on water and sun alone, then it’s time you “listened” to your plants’ body language. If they look glum, lazy or colorless, they’re probably waiting for a little nutrient boost – courtesy of you!

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Fertilizing Basics

It's a confusing world out there. Just looking at the selections at the fertilizer section of any gardening store will leave you wondering -- "Which of these do I really need?!" Not only do you need to choose between organic and non-organic kinds, but there are choices under each category as well! To help clear up their uses, here's a quick primer.  

Organic fertilizers are derived purely from plant or animal matter. They are environment-friendly (both in production and in use), are not harmful to beneficial soil microbes, and they don't leave chemical residues. To read more about organic gardening, click here.

Inorganic or chemical fertilizers are products of the petrochemicals industry. They are faster acting, however, they also leach out faster and require much more frequent application. Unlike organic fertilizers which are slow acting, chemical fertilizers have more chances of burning plant roots in case you accidentally apply too much. One major disadvantage to using them is that they can harm many of the important microorganisms that live in the soil. And if used extensively on edible plants, they also affect the overall nutritive value, aroma and flavor of the harvest.
    
Using Complete Fertilizers  

Whether you opt for organic or chemical fertilizers, you couldn't do without a complete fertilizer. This means it's a fertilizer that offers the three most important nutrients your plants need.

Nitrogen, phosphorus and potassium. The most popular complete fertilizer is a chemical one. It is so popular, in fact, that it has come to be known all over the metropolis by the generic name 'complete fertilizer' -- also called Triple 14. That means it's made up of 14% nitrogen (N), 14% phosphorus (P), and 14% potassium (K). The rest would be fillers. This sort of division of nutrients, wherein each is delivered in equal parts as the others, is called a BALANCED complete fertilizer. Read the label of your fertilizer and you will almost always find the three numbers that will indicate its N-P-K ratio. (The numbers and their corresponding nutrients are always in that order.) The numbers can be 19-19-19, or 13-13-13, or 21-21-21. All of these are complete and balanced, only in varying strengths.
    

There are also complete fertilizers that are not balanced. Meaning, the N-P-K is not in equal numbers. You'll find 9-45-15, or 30-10-10, or 18-6-12. Some formulas are called BLOOM BOOSTERS, others are called GROWTH FORMULAS. This just means that one formula has more of one nutrient than the other. And if you've read the article above, then you should understand why your plant may need one formula more than the other. Does it need to produce more leaves? Is it a young plant that needs to produce more roots and stronger stems first? Does it have flowers but they're too few and small? Understanding the three numbers actually helps you match the appropriate NPK ratio to the specific needs of your plants. Both organic and chemical fertilizers have an NPK analysis usually printed on their package.

Now, if you read the fertilizer label more closely and you find the words "Micronutrients" somewhere in there, that means this fertilizer is not just giving your plants the basics, but is providing your plants the other essentials for overall health. If you were to liken it to vitamin pills, this one offers vitamins from A to Zinc. It costs more than your generic 14-14-14, but your plants will look and feel a lot better with it.     

Targeted Fertilizing   Meanwhile, some gardeners want to fertilize like snipers. Meaning, they want to hit the bull's eye -- they just want one particular nutrient to address a particular problem. For instance, some gardeners simply want urea (46-0-0), a single-nutrient fertilizer to produce a greener lawn. Or someone else prefers ammonium sulfate for his roses to produce more leaves and adjust the soil pH at the same time. This is similar to people who just take some Vitamin C for their colds or Calcium for their bones.

The forms also vary, and this is to suit your individual gardening style and preference. Powdered fertilizers are dissolved in water and sprayed or watered onto the plants. Granular (like the popular Triple 14 and Urea) is meant to be broadcast on the soil or potting mix and doused with water to dissolve it. Slow-release fertilizers are buried slightly in the soil or potting mix and are replenished after the recommended period (anywhere from three to nine months). Liquid is diluted with water and sprayed on the leaves or used as soil drench.

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Feed Through the Leaves 

All About Foliar Fertilizers 
Most people understand that a plant's roots take up nutrients from the soil. Perhaps this is why it puzzles a lot of people when we advice them to spray fertilizers on the leaves. 

Foliar or leaf feeding is the most efficient way to fertilize. Studies show that as little as 10% of nutrients may be taken up by a plant's roots when the fertilizer is applied to the soil, whereas with foliar feeding, as much as 90% may be absorbed. Nutrients applied directly to leaves are absorbed and then pass into the plant's circulatory system. Once there, the nutrients are distributed throughout the plants' tissues.

Foliar feeding is especially beneficial when the plant is growing rapidly, is about to bloom or has just set fruit. Spray a fine mist to cover all leaf surfaces. For best absorption, spray in the early morning or late afternoon because that's when the leaf pores open to regulate the passage of moisture, oxygen and carbon dioxide through the leaves. Avoid spraying in the heat of the day when some foliar feeding mixtures could scorch leaves and petals -- and would probably just evaporate too soon to be of any good.

If your plants display any signs of disease, spray only in the morning so the leaves will dry quickly and reduce the infection's spread. Foliar sprays are absorbed relatively quickly, in one to 24 hours. Should it rain within a day, re-spray. Likewise, don't water your plants from above until a day after spraying. If you must water, apply the water directly to the soil.

A word of caution: Not all fertilizers are designed for foliar feeding. Some chemical fertilizers may actually burn when they come in contact with any plant part. Read label instructions carefully. For herbs, fruits and vegetables, liquid seaweed and fish emulsion are excellent organic choices.

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Mad About Manure

Earthworm castings and guano (bat droppings) have long been recognized as nature's best fertilizers. Chicken manure is so strong that we are often warned of the chances of it actually burning crops. It has also been rumored that people exposed to it for extended periods are more prone to stroke. Make sure it is aged and composted before use.

Goat manure is said to be mild enough to use immediately; no curing necessary. So are rabbit droppings. Simply spread them on the ground, scratch them into the soil surface and add water.

Never use dog or cat droppings in your garden; the produce of even the healthiest pets often contains disease organisms.

Pig manure may be used, but only if you know the animals have been fed grain and vegetables, not fat-laden table scraps that can attract disease organisms.

Horse and cow manure are very good choices to rejuvenate tired, old garden soil of existing lawns and gardens or to enrich and condition newly laid out topsoil. Sun-dried horse manure is best.

You can also keep a drum full of manure tea, ready to feed your plants organically. Simply fill a big garbage pail about 1/8 full of fresh cow or horse manure then fill up with water. Wait a week or two, stirring occasionally. Dilute it until it's the color of weak tea before watering it straight into the potting mix or soil. DO NOT SPRAY ONTO THE LEAVES OF YOUR EDIBLES. The tea could contain harmful bacteria that might end up in your salad! It's perfectly all right as a soil drench, however, especially for all your flowering and ornamental plants. Add water to the pail after every use. When it becomes the color of weak tea, you can start all over again. Add the old manure into your compost pile.

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Seaweed For Your Plants

A long time ago, gardeners who lived by the sea discovered that seaweed was good for their plants. Back then, they didn’t really know why, but now scientists have found that seaweeds contain a treasure trove of plant-growth stimulants, vitamins, chelating agents, trace minerals, enzymes, and amino acids. Perhaps the most important element in seaweed are the organic growth hormones.

Studies have shown that seaweed can produce dramatic results in plants: geraniums and orchids produce more flowers per plant; roses become less sickly; grapes are sweeter; cucumber yields increase by 40 percent and the fruits suffered less often from softening and rotting. Improved yields after seaweed treatments were measured in potatoes, sweet corn, peppers, tomatoes, apples, strawberries, okra and oranges. Increased seed germination and improved capacity to absorb trace elements are other documented benefits for plants.

You can use liquid seaweed as a soil drench or sprayed onto leaves. There is evidence that a fine mist allows more efficient absorption of the seaweed.

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