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Fertilizer Basics

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Don't let your plants go hungry.

To look their best, most perennials require regular fertilization.

According to a recent Gallup Gardening Survey, less than half of the country's home gardeners use any kind of fertilizer on their lawns or gardens. This statistic unfortunately indicates that gardeners aren't getting as many flowers or as many fruits and vegetables as they should. Beyond that, they are most likely struggling with disease and insect problems that could be avoided. Well-fed plants are healthier, produce more, and are more beautiful to look at.

Plant Nutrients 101

Plants need to be fertilized because most soil does not provide the essential nutrients required for optimum growth. Even if you are lucky enough to start with great living organic garden soil, like the many we carry as your plants grow, they absorb nutrients and in so doing strip fertility from the soil. Remember those tasty tomatoes and aromatic medicinal flowers you grew last year? It took nutrients from the soil to build those plant tissues and floral clusters. By fertilizing your garden, you replenish lost nutrients and ensure that this year's plants have the food they need to flourish.

There are six primary nutrients required by plants. They get the first three—carbon, hydrogen and oxygen—from air and water. The remaining nutrients are nitrogen, phosphorus and potassium.

Nitrogen helps plants make the proteins they need to produce new tissues. In nature, nitrogen is often in short supply so plants have evolved to take up as much nitrogen as possible, even if it means not taking up or displacing other necessary elements. If too much nitrogen is available, the plant may grow abundant foliage but not produce fruit or flowers. Growth may actually be stunted because the plant isn't absorbing enough of the other elements it needs. Deep green leaves are often an indication of excess nitrogen, as is the telltale “claw” of leaves curling like a ram’s horn.

Phosphorous stimulates root growth, helps the plant set buds and flowers, improves vitality and increases seed size. It does this by helping transfer energy from one part of the plant to another. Organic matter and the activity of soil microorganisms also increase the availability of phosphorus..

Fertilizers

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Take your garden from good to great with the right fertilizer.

Potassium improves overall vigor of the plant. It helps the plants make carbohydrates and provides disease resistance. It also helps regulate metabolic processes.

There are three additional nutrients that plants need, but in much smaller amounts:

Calcium is used by plants in cell membranes, at their growing points and to neutralize toxic materials. In addition, calcium improves soil structure and helps bind organic and inorganic particles together.

Magnesium is the only metallic component of chlorophyll. Without it, plants can't process sunlight.

Sulfur is a component of many proteins.

Finally, there are eight elements that plants need in tiny amounts. These are called micronutrients and include boron, copper and iron. Healthy soil that is high in organic matter usually contains adequate amounts of each of these micronutrients.

Organic vs. Synthetic

Do plants really care where they get their nutrients? Yes, because organic and synthetic fertilizers provide nutrients in different ways. Organic fertilizers are made from renewable naturally occurring mineral deposits and organic material, such as bone or plant meal or composted manure. Synthetic fertilizers are made by chemically processing raw materials, and their manufacture is a significant contributor to globally increasing greenhouse gas emissions and climate change.

In general, the nutrients in organic fertilizers are not water-soluble and are released to the plants slowly over a period of months or even years. For this reason, in outdoor applications organic fertilizers are often applied in the fall so the nutrients will be available in the spring. These organic fertilizers stimulate beneficial soil microorganisms and improve the structure of the soil. Soil microbes play an important role in converting organic fertilizers into soluble nutrients that can be absorbed by your plants. In most cases, organic fertilizers and compost will provide all the secondary and micronutrients your plants need.

Synthetic fertilizers are water-soluble and can be taken up by the plant almost immediately. In fact applying too much synthetic fertilizer can "burn" foliage and damage your plants. Synthetic fertilizers give plants a quick boost but do nothing to improve soil texture, stimulate soil life, or improve your soil's long-term fertility. Because synthetic fertilizers are highly water-soluble, they can also leach out into streams and ponds as recognized pollutants. For the long-term health of your garden, feeding your plants by building the soil with organic fertilizers and compost is best. This will give you soil that is rich in organic matter and teeming with microbial life.

Foliar Feeding?

Plants can absorb nutrients eight to 20 times more efficiently through their leaf surfaces than through their roots. As a result, spraying foliage with liquid nutrients can produce remarkable yields. For best results, spray plants during their critical vegetative growth stages such as transplanting time, and before the onset of flowering or fruit set.

What About pH?

Even if proper nutrients are present in the soil, some nutrients cannot be absorbed by plants if the soil pH is too high or too low. For most plants, soil pH should be between 6.0 and 7.0 Keep in mind that it's best to raise or lower soil pH slowly over the course of a year or two. Dramatic adjustments can result in the opposite extreme, which may be worse than what you started with. Once again, a helpful solution is to apply compost. Compost moderates soil pH and is one of the best ways to maintain the 6.5 ideal. Like a good compost, a living organic soil like ours, has the capacity to buffer your plants against pH swings and can largely remove the need to worry about pH adjustments entirely.

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Our slow-release, granular GSC Organic Tomato Fertilizer (5-6-5) gives your tomatoes all the nutrients they need, including plenty of phosphorus for big, abundant fruit. For a healthy start, mix a handful into the soil at transplant time and then side dress when tomatoes begin to set fruit. Also ideal for peppers and eggplant.

How to Choose a Fertilizer

In most cases, an all-purpose, 5-5-5 fertilizer will provide the nutrients all plants need for healthy growth. If a soil test reveals certain nutrient deficiencies, or if you want to tailor your fertilizer to the needs of particular plants (tomatoes vs. flowering medicinal plants), you can select a special formulation. What you choose will depend on your soil and what you are growing.

The three numbers that you see on a fertilizer label, such as 5-5-5, tell you what proportion of each macronutrient the fertilizer contains. The first number is always nitrogen (N), the second is phosphorus (P) and the third is potassium (K). This "N-P-K" ratio reflects the available nutrients —by weight—contained in that fertilizer. For example, if a 100-pound bag of fertilizer has an N-P-K ratio of 5-7-4, it contains 5 pounds of nitrate, 7 pounds of phosphate (which contains phosphorous), 4 pounds of potash (which contains potassium) and 84 pounds of filler.

Note that the N-P-K ratio of organic fertilizers is typically lower than that of a synthetic fertilizer. This is because by law, the ratio can only express nutrients that are immediately available. Most organic fertilizers contain slow-release nutrients that will become available over time. They also contain many trace elements that might not be supplied by synthetic fertilizers.

Fertilizers offered by Green State Gardener are all organic, no if’s ands or buts. To build the long-term health and fertility of your soil, we recommend using granular organic fertilizers. Supplementing with a water-soluble organic fertilizer ensures that your plants have the nutrients they need when they're in active growth.

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