Like humans and other living things, plants have specific nutritional needs in the form of fertilizers. These nutrients promote growth, fruit and flower production, and healthy root development. Fertilizers are often the key to providing our plants with their macronutrient and micronutrient needs, as well as trace minerals and other elements.
Clearly, long-term crop success depends on the ability to identify the right fertilizer for each plant, at a specific stage of growth – and then apply it in the best way and at the right dose. Understanding Fertilizer rates and applications allows you to better evaluate what types of fertilizers to use and when. This essential guide to understanding fertilizers outlines the basics of fertilizing to help your ornamentals, edible plants, shrubs, and lawns thrive.
What is fertilizer?
Essentially, plant fertilizers list a ratio that describes the amount of each macronutrient contained in the formula. These three-number ratios refer to nitrogen, phosphorus, and potassium, in that order. Other trace elements and secondary nutrients will also be contained in varying amounts.
There are many forms of fertilizer available to feed your plants, shrubs and lawn. They can be organic fertilizer types or general synthesis feed. The formula can be spray, granular, or powder. No matter what type of garden fertilizer you have, the corresponding nutrient amounts are always in the same order.
(Image credit: Rafa Jodar/Getty Images)
Why do we need to use fertilizers?
Knowledge how trees grow and what they need can have a huge impact on how we approach the task of feeding them. Plants require around 17 major elements. Of these, carbon, hydrogen and oxygen are absorbed through air and water. The remaining 14 elements are mostly found in the soil. When the soil is depleted or lacking an essential element, gardeners can use a formula to provide whatever is missing. This ensures that plants grow stronger and healthier, which in turn reduces disease and pest problems.
Fundamental to good plant health is an understanding of NPK fertilizerrefers to three elements: nitrogen, phosphorus, and potassium. This ratio is found on all purchased fertilizers and indicates the amount of each. In addition to the NPK nutrients, a table next to them will usually list any secondary nutrients as well as minerals. Secondary nutrients are calcium, magnesium, and sulfur. Plants do not need much of these nutrients. Micronutrients are copper, molybdenum, nickel, chlorine, zinc, iron, manganese, and boron.
Fertilizer code decoding
The three numbers listed on a fertilizer purchased for plants refer to the amount Nitrogen, phosphorusAnd potassiumFor example, a 10-10-10 bag weighs 100 pounds, or balanced fertilizercontains 10 pounds of each macronutrient. The same size bag but with a 10-20-15 ratio would contain 10 pounds of nitrogen, 20 pounds of phosphorus, and 15 pounds of potassium.
Some plants, such as foliage plants, require higher levels of nitrogen. This is why we use high nitrogen fertilizers on lawns. A plant grown primarily for its flowers may need a higher phosphorus formulation. Some of these are sold as superphosphate products, which are lower in nitrogen and higher in phosphorus. Knowing your plant’s needs is key to providing the right fertilizer.
(Image source: Wihteorchid / Getty Images)
Different types of fertilizers
Plant fertilizers can be organic or synthetic. You will see different application modes (eg. slow exit or fast) as well as varying proportions of nitrogen, phosphorus, and potassium. The simplest and oldest fertilizers are well-rotted manure or compost. It can be difficult to determine exactly how much of each nutrient is in each of these. On average, organic garden fertilizer Manure is fairly balanced in all three macronutrients, but they are contained in small amounts. Manure is much higher in nitrogen. Compost is more of a soil conditioner, while manure is usually a top dressing or pre-planting soil conditioner.
Commercial fertilizers start with raw materials such as sulfur, ammonia, and rock phosphate. These items are crushed, mixed, and chemically processed. Organic fertilizers are mineral rocks combined with natural plant and animal derivatives. Within each of these categories, you can find products in many forms. Granular fertilizers are designed to be applied around the root zone. Liquids are diluted with water and can be applied as a soil drench or foliar spray. Powders are similar to granular fertilizers and are applied to the soil in precise pound-per-acre measurements.
Choosing the Best Fertilizer for Your Needs
Before you begin your fertilizer exploration, it is important to conduct a soil test. Not all soils are the same and not all plants respond to soil in the same way. If soil test If you find areas that are lacking in essential nutrients, choose a formula with a higher nutrient content. Soil tests will also reveal the pH of the soil. The pH will affect the plant’s ability to absorb nutrients.
Vegetables like a pH of around 6.5, grasses need 6-7, and most trees and shrubs like 5.5-5.6, while acid-loving plants like blueberries need a pH of 5. Once you’ve determined the right pH for your plants, you can address their individual nutrient needs. So before you choose a fertilizer for your vegetable garden or choose a best lawn foodor The right formula for rosesMake sure you know what’s going on in your soil. Once you’re ready, determine your preferred method of fertilizer delivery and choose a formula that’s easy to use and effective.
(Image source: Dean Clarke / Shutterstock)
When to Fertilize Your Plants
One of the biggest mistakes people make when fertilizing their plants is choosing the wrong time. Misjudgment best time to fertilize can do more harm than good. Most plants should not be fertilized in the winter. In cold areas, avoid fertilizing late in the season as this can promote new growth that will be sensitive to frost in the fall. In general, spring fertilization Recommended for many plants that are about to begin active growth. There are both fast-release and slow-release fertilizers. In colder areas, fast-release is best because slow-release formulas require soil temperatures of around 70°F (21°C) to release nutrients.
Fertilization frequency depends on the plant. For example, tomatoes are a nutrient-dense plant. If you are looking for Fertilize tomatoesRemember that they need more plant food than ornamental grasses, for example. It is important not to over-fertilize as this causes runoff that can negatively impact waterways. It can also lead to unsustainable plant growth.
How to use fertilizer for plants
Allows for plant type, time of year and even weather conditions when adding foodThere are several ways to fertilize plants. One way is to spread it before planting and mix it into the soil to a depth of four inches (10cm). Another method is band feeding, in which the plant food is arranged in bands a few inches below the soil surface to feed the roots.
Foliar spraying (spraying fertilizer directly onto leaves) is especially effective for plants with large leaves. Base fertilizers are formulated gently to avoid damaging young or newly transplanted plants. Top dressing (spraying fertilizer for vegetable garden have begun to grow) increase yields, but must be watered thoroughly. If you have questions about fertilizing in your area, contact your local extension service for information appropriate to your area.
(Photo source: Sutthiwat Srikhrueadam / Getty Images)
frequently asked Questions
What is the most important fertilizer for plants?
The answer to this question will depend on whether you want to fertilize flowering or fruit trees, large shrubs, trees or lawns. It will also depend on the stage of growth of the plant (for example, plants that have started to produce fruit will need phosphorus and potassium, while nitrogen is good for promoting leaf growth).
As a general rule, however, the most important fertilizer is an all-purpose 10-10-10 NPK (nitrogen, phosphorus, potassium) blend. This can be in granular form (as a slow-release feed) or liquid form (applied about once a month during active growth or more frequently depending on the plant).
Should you water your plants before or after fertilizing?
This question has sparked much debate in the gardening community, and expert opinions often differ on the order of watering and feeding. Again, this can depend on the plant, the time of year, and the type of feed you have chosen. Watering a few hours before fertilizing can help, as it can ‘prepare’ the soil or compost and reduce the risk of air pockets forming. However, granular feeds work best if you water the plant after applying. Indeed, some feeds rely on water to facilitate plant uptake. If you are adding a feed to your lawn, some experts recommend waiting a day or so before watering.
