Danny Lipford

The Debate over Organic vs. Chemical Fertilizers

Fri, 29 Aug 2008 19:33:38 +0000

Ask most any gardener whether they prefer organic or chemical fertilizer, and chances are you’ll spark a lively debate. However, if you could ask your plants the same question, you’d find out that at the most basic level, they really can’t tell the difference – nutrients are nutrients.

Yet there ARE significant differences between organic and chemical fertilizers in terms of nutrient availability and the long-term effects on soil, plants, and the environment. So how does a conscientious gardener decide?

Terminology

To begin with, the terminology can be confusing, since labels and gardeners freely throw around words like organic, natural, inorganic, chemical, synthetic, artificial, and manufactured. The good news is that the choice can be reduced to either organic or chemical fertilizers.

Organic Fertilizer

The words “organic” or “natural” in this case simply means that the product is only minimally processed, and the nutrients remain bound up in their natural forms, rather than being extracted and refined. In the case of fertilizer, “organic” does NOT refer to the standards of processing associated with food.

Organic fertilizer is usually made from plant or animal waste or powdered minerals. Examples include manure and compost, as well as bone and cottonseed meal. They are usually sold as “soil conditioners” rather than as fertilizer, because the nutrient ratios are difficult to guarantee. Organic fertilizers may be processed in a factory, or, in the case of manure and compost, at a farm.

There is also a growing selection of more highly processed products now available, with labeled analysis of nutrients and contents. For example, ScottsMiracle Gro Organic Choice Plant Food is a manufactured product composed entirely of chicken litter and ground up feathers, with an N-P-K ratio of 7-1-2. Garden Safe Organic Plant Food is made of poultry manure with a label very similar to chemical fertilizers.

Advantages of Organic Fertilizer:

In addition to releasing nutrients, as organic fertilizers break down, they improve the structure of the soil and increase its ability to hold water and nutrients. Over time, organic fertilizers will make your soil–and plants–healthy and strong.
Since they are the ultimate slow-release fertilizers, it’s very difficult to over fertilize (and harm) your plants.
There’s little to no risk of toxic buildups of chemicals and salts that can be deadly to plants.
Organic fertilizers are renewable, biodegradable, sustainable, and environmentally friendly.
Although rather expensive in packages, you can make your own organic fertilizer by composting or find inexpensive sources—such as local dairy farms—that may sell composted manure.

Disadvantages of Organic Fertilizer:

Microorganisms are required to break down and release nutrients into the soil. Since they need warmth and moisture to do their job, the effectiveness of organic fertilizer is limited seasonally. The good news is that these microorganisms obtain energy from decaying plant and animal matter, so an application of organic fertilizer provides a complete package of nutrients for your soil.
Organic fertilizers break down according to nature’s rules, so they may not release nutrients as soon as you need them. You have to be patient – you won’t see improvement overnight. In fact, you may actually see a deficiency in your plants during the first couple of months until the first application breaks down. Hang in there! You’ll most definitely be rewarded.
Nutrient ratios are often unknown, and the overall percentage is lower than chemical fertilizers. However, some organic products are actually higher in certain nutrients.

Chemical Fertilizers

Chemical or manufactured fertilizers have been refined to extract nutrients and bind them in specific ratios with other chemical fillers. These products may be made from petroleum products, rocks, or even organic sources. To cause more confusion, some of the chemicals may be naturally occurring. The difference is that the nutrients in chemical fertilizers are refined to their pure state and stripped of substances that control their availability and breakdown, which rarely occurs in nature.

Advantages of Chemical Fertilizer:

Since nutrients are available to the plants immediately, improvement occurs in days.
They are highly analyzed to produce the exact ratio of nutrients desired.
Standardized labeling makes ratios and chemical sources easy to understand.
They’re inexpensive.

Disadvantages of Chemical Fertilizer:

Chemical fertilizers are primarily made from nonrenewable sources, including fossil fuels.
They grow plants, but do nothing to sustain the soil. The fillers do not promote life or soil health, and even packages labeled “complete” do not include the decaying matter necessary to improve soil structure. In fact, chemical fertilizers don’t replace many trace elements that are gradually depleted by repeated crop plantings, resulting in long-term damage to the soil.
Because the nutrients are readily available, there is a danger of over fertilization. This not only can kill plants but upset the entire ecosystem.
Chemical fertilizers tend to leach, or filter away from the plants, requiring additional applications.
Repeated applications may result in a toxic buildup of chemicals such as arsenic, cadmium, and uranium in the soil. These toxic chemicals can eventually make their way into your fruits and vegetables.
Long-term use of chemical fertilizer can change the soil pH, upset beneficial microbial ecosystems, increase pests, and even contribute to the release of greenhouse gases.

Making a Choice

If you wish to live in harmony with nature and make a lasting improvement in your own patch of earth for generations to come, organic fertilizers outweigh chemicals by leaps and bounds. Can a shot of chemical fertilizer make your containers spill over with blossoms, and give you the biggest tomatoes and greenest lawn in the neighborhood? Absolutely. Just be sure you understand what’s really happening to the earth under your feet, so that you’ll make your choice consciously.

Further Information

Fertilizer 101

Fri, 22 Aug 2008 21:27:31 +0000

Simply put, fertilizers are like vitamin supplements for plants. When used properly, they can treat plant “malnutrition” and promote rapid growth and blooming. When used improperly, however, they can be harmful to both plants and the environment, so it’s helpful to understand the basics of fertilizer makeup and application in order to choose wisely.

Much like supplements for humans, in order to choose the best one you must consider:

What nutrients you need for which purpose.
The dosage and ratio of nutrients.
The source – manufactured, processed, or natural.

Fertilizer Types

Fertilizer can be thought of as:

Organic fertilizer should not be confused with the familiar eco-friendly term. “Organic” in this case simply refers to fertilizers composed of plant and animal matter, or naturally-occurring minerals, that have been minimally processed and leave the nutrients in their natural states. Examples include manure, compost, peat, cottonseed meal, and bone meal, as well as some packaged fertilizers.
Chemical fertilizers are processed from natural or synthetic chemical sources, from which the nutrients have been industrially extracted and combined with fillers to create pellets, powders, or liquids.

Fertilizer can be made by:

Natural processes, such as composting.
Chemical processes in manufacturing.
Mining and processing of minerals.

Fertilizer Makeup

In order to grow, thrive, and multiply, plants need a variety of nutrients:

Carbon, hydrogen, and oxygen: easily obtained from air and water.
Nitrogen, phosphorus, and potassium: sometimes referred to by their chemical symbols N-P-K. They are considered the “primary nutrients” and are usually the main active ingredients in fertilizer, indicated in order by the three numbers on the package label (such as 10-10-10 or 21-7-14).
Secondary nutrients: Calcium, sulfur, and magnesium along with trace elements such as boron, zinc, copper, chlorine, molybdenum, manganese, and iron, are also important to plants and may be present in fertilizer.

On the label of most any package of manufactured fertilizer, you’ll see three numbers, such as 10-10-10 or 21-7-14. These numbers refer to the percentage of nitrogen, phosphorus, and potassium in the package. To understand the labeling, you need to look at the numbers in two ways:

Percentage: 21-7-14 means that the package contains 21% nitrogen, 7% phosphorus, and 14% potassium. The rest is filler. Packages with higher percentages are stronger, so you can use less.
Ratio: 21-7-14 has a ratio of 3-1-2. Both 10-20-10 and 5-10-5 have ratios of 1-2 -1. If you’re not into math, simply look at the numbers as “big, medium, or small” and you’ll do just fine.

Guide to Fertilizer Ratios

1-1-1 (such as 10-10-10): General purpose.
2-1-1: Trees and established lawns, leafy vegetables.
1-2-1: Fruits, vegetables, and seeds, flowers, transplants.
3-1-2 or 2-1-2: Stressed lawns and fall lawn feeding.
1-2-2: New lawns.

To choose the correct fertilizer, you’ll want to understand the three primary nutrients and how they work.

Nitrogen (10-10-10)

Nitrogen is what makes plants green and influences growth of leaves and stems. Many “all-purpose” fertilizers have a high nitrogen content for that quick burst of green growth that lets you know it’s working. Nitrogen deficiency is evident by yellowing of leaves or grass blades. If you overdo it on nitrogen, your plants will be huge and lush but not very strong, as that rapid growth is more susceptible to diseases, insects, and frost damage.

In manufactured fertilizers, nitrogen is often processed from fossil fuels, usually natural gas. Other sources of nitrogen fertilizer include blood meal, alfalfa meal, fish emulsion, gelatin, and manure. Also, legumes such as alfalfa, beans, and clover have the ability to “fix” atmospheric nitrogen into the soil. Planting a legume cover crop, then tilling the plants into the soil, is an excellent natural fertilizer when preparing a garden.

Use nitrogen during the growing season, but taper down before fall. You don’t want a lot of new, tender growth as the plant faces freezing weather.

Phosphorus (10-10-10)

Phosphorus primarily influences roots, flowers, and fruits/seeds. Manufactured fertilizer labeled “bloom booster” probably has a heavy dose of phosphorus, as do fertilizers packaged for fruits and vegetables. Phosphorus deficiency is evident in red/purple leaves and stunted growth.

In addition to chemical fertilizers, natural phosphorus sources include rock phosphate, bone meal, and composted fruit. Some states have regulations about how much phosphorus you can apply to your lawn, due to potential pollution from the chemical compounds. Check with your agricultural extension service for more information.

Mix phosphorus (such as 0-19-0 or a natural source) into the planting hole when transplanting larger plants and shrubs, to help establish strong roots. It’s also helpful in containers to encourage flowering.

Potassium (10-10-10)

Potassium is an “all-over” nutrient, especially good for winterizing and stress-proofing. It works throughout plants at the cellular level. Potassium deficiency results in weak branches, failure to thrive, and dying or curling leaves.

Natural sources of potassium include potassium sulfate, rock sand, granite dust, wood ash, kelp meal and a mineral called Sul-Po-Mag (sulfate of potash-magnesia).

Use potassium in the fall to prepare plants for winter, and also in the spring if you expect drought or other stressful conditions. Potassium is important for new plants and lawns. Although it doesn’t produce as visible an effect as nitrogen, the benefits pay off in the long run with healthy, strong, tough plants.

Further Information

For more information, check out our article on The Debate over Organic vs. Chemical Fertilizers as well as videos on Fertilizer Selection and Fertilizer Application.

Breaking up Clay Soil

Fri, 01 Aug 2008 14:42:15 +0000

Many years ago I used gypsum pellets to break up clay soil. We can not find them anymore but the problem of the hard packed clay soil still exists. Is there a different product that will solve this problem? - Barbara

Hi Barbara,

Gypsum is still available, but it’s not recommended for general use. Gypsum (calcium sulfate) is used specifically as a chemical remedy in crusty clay soils containing excess sodium (called “sodic soils”). These soils usually occur in western states and are best identified by chemical soil analysis.

For general purposes, routinely working organic material into your garden—such as well-rotted compost—will both condition and aerate the soil. The compost continues to break down underground, adding nutrients and workability to the soil, but this breakdown also means that the process will need to be repeated every year or so for lasting results. In my garden, I’ve had good luck with an aggregated slate product called PermaTill. Worked into the soil, it not only keeps the soil loose and uncompacted, but also acts as a deterrent to moles and voles.

Landscape Lasagna

Tue, 20 Mar 2007 16:10:50 +0000

Creating great soil is like making good lasagna according to Florida landscaper Rachel DeToro. It’s all about layers. Not pasta and cheese. Organic material on top of organic material. Rachel’s recipe starts with mushroom compost on the bottom, followed by a layer of pine bark mulch (finely grounded). For the next layer, Rachel uses seaweed (rinsed to remove salt) though she says leaves or clippings work equally well if seaweed isn’t available to you. Finally, another layer of compost and the soil is ready to cultivate and plant. To protect the soil and retain moisture, top the bed off with a layer of pine straw or leaf mulch.

Ashes for Plants

Thu, 08 Feb 2007 01:24:41 +0000

The potassium in wood ashes encourages strong stems in plants while the phosphorus in the ashes encourages root growth. Soils low in potassium often benefits from wood ash but be careful with acid-loving plants such as blueberries, rhododendrons and azaleas. To use wood ash safely, add a small amount to your compost pile. Here the wood ash will help maintain a neutral condition, which is the best environment to help microorganisms break down organic materials. Sprinkle ashes on each layer of compost as the pile is built up and allow the ash to dissolve in the compost. Also, be sure not to use any pressure-treated wood ashes.

Compost Bin

Tue, 23 Jan 2007 16:30:38 +0000

Even the most novice gardeners know the benefits of using compost in their gardens, but nobody wants to look at a compost pile. One solution is a pre-fab compost bin made of plastic. Most of these units are compact in size and have removable lids that allow you to add material to the compost. The design should allow plenty of air and water to get into the mix, so the organic material can properly decompose. The only real work included here is occasionally stirring or rotating the compost.

Fertilizer Selection

Fri, 15 Dec 2006 16:17:12 +0000

Choosing the right fertilizer for your lawn can be a confusing proposition. The Turf Expert Dr. Trey Rogers tells us it doesn’t actually have to be that way. According to Trey, your local garden center usually selects only what you need in your area for that given time of year. The numbers that you see on the packaging give you an indication of what you are getting. They represent the percentages of nitrogen, phosphorus and potassium. In the fall you want a product with all three numbers roughly equal. In spring you’ll want the first number (nitrogen) to be larger in comparison because your lawn will need more nitrogen to put on new growth and green up. Often products with identical percentages have different prices. In these cases the cost difference is usually about longevity. The more expensive product should last longer in the lawn.

Fertilizer Application

Thu, 07 Dec 2006 15:46:30 +0000

Dr. Trey Rogers, Briggs and Stratton Yard Doctor, gives us some great tips for applying fertilizer.

If possible, use a broadcast spreader instead of a drop spreader. This minimizes the chances of leaving lines in the lawns.
Follow the directions on the bags as far as the amount you use. More is not better.
Try to apply fertilizer before a good rain to insure that it gets into the ground.

Mulch

Mon, 23 Oct 2006 16:35:13 +0000

As a gardener, mulch can be one of your greatest allies. This often-neglected stuff maintains soil moisture and temperature while blocking the growth of weeds around plants you do not want. While there are lots of types of mulch you can use, there are some you may want to avoid. Saw dust or wood chips (from a saw mill or cabinet shop) that have not rotted or decomposed may rob nitrogen from your soil and therefore your plants. Some mulch, like oak leaves and pine straw, will add acid to your soil (this may be good or bad depending on your soil’s pH). Finally, if you’re looking for a deal, don’t buy mulch by the bag. Find a nursery or landscaper who will sell it by the truckload and pick it up or have it delivered.

Seed Feed

Thu, 21 Sep 2006 18:13:00 +0000

To keep seedlings healthy and growing feed them gelatin. Any flavor is okay as long as it’s sweetened with sugar - not artificial sweeteners. The gelatin contains the nutrient nitrogen, which helps plants form green leaves. The sugar actually feeds beneficial microbes already in the soil that help young plants defend against disease causing organisms. Fill the flats with seed-starting mix, sow the seeds and use an old saltshaker to lightly sprinkle the gelatin powder over the seedlings. Press the seeds and gelatin in and cover with a thin layer of your starting mix. Mist the soil and cover with wet paper towels. Simply place the flats in a warm area (somewhere around 65 to 75-degrees). Keep the towels moist by occasionally misting them and check the flats daily for sprouts. As soon as you see growth, remove the paper towels. After the plants take off, feed them liquid fertilizer with a teaspoon of gelatin powder mixed into each gallon.