Close up of a gardener digging a plant out of their garden

Fertilizing Your Garden

Healthy gardens are finely-tuned and smooth-running machines that add not only value but a food source or a beautiful aesthetic to your property. Providing your garden with the right nutrients at each stage of each plant's growing cycle is essential to achieving the best results possible. The information below will teach you everything you need to know about how healthy soil impacts plant growth, the nutrients plants need, which fertilizers to choose, and so much more.

The Importance of Healthy Soil

Let’s start with the basics. Healthy soil must be high in organic content. You cannot grow living plants from seeds if the soil is barren or lacking the proper nutrients. High-quality soil does three things for any plant growing within it:

  1. Feeds – When soil is well-cared for and contains the right balance of nutrients, it helps plants create more nutrients including protein. There are billions of microorganisms living in the soil that produce amino acids. Plants convert the amino acids to protein which nourishes any animal that eats those plants. If soil becomes neglected, these nutrient producing organisms will die and your plants will suffer as a result.
  2. Cleans – The more plants you have, the more clean air is produced. In addition, nutrient-dense soil produces less dust. Neglected soil tends to be looser which can contribute to erosion and air pollution, potentially causing harmful effects on the environment!
  3. Protects – Developing deep root systems is extremely important for plants. This gives them more stability to grow, allows them to better survive droughts, and more easily search for nutrients. Looser soil poses a danger to supporting plants and their root systems. Nourished soil provides stability and nutrients naturally. In addition, the bacteria and fungi that take up residence in healthy soil provide a natural defense system against disease.

Essential Plant Nutrients

To survive, plants need 17 different nutrients and all of these are considered essential because without them, plants would not live long. Of those 17 nutrients, 14 are provided by healthy soil and the rest come from the air and water. However, there are 3 nutrients that plants need in larger quantities, nitrogen, phosphorus, and potassium.

You may have already seen indicators of these nutrients on bags of fertilizer. Each bag of fertilizer will have an NPK ratio printed on its label. The N stands for nitrogen, the P for phosphorus, and the K for potassium. Each nutrient is needed in more abundance depending on the stage each plant currently is in their lifecycle. Nitrogen is particularly important for growth, while phosphorus is essential for flowering/fruiting, and potassium helps to support root systems.

Matching Nutrients To Growth Stages

NPK Nutrient Diagram: Nitrogen (N), Phosphorus (P) and Potassium (K)

Nutrients are rarely needed in exactly the same balance as each other. One or two nutrients tend to dominate when it comes to what plants need in a certain life stage. In simple terms, plants go through 3 main life stages: the seed/germination, vegetative stage, and flowering/fruiting.

Every plant life cycle begins with a seed. When planted, a seed needs warmth, water and sometimes light in order to start germinating. During this stage, the seed embryo starts to emerge from its tough outer coating. A stem and small roots also start to form. Nutrient needs tend to be balanced during this stage.

In the following growth/vegetative stage, seedlings undergo intense stem and leaf growth. Nitrogen is the most important nutrient needed for plants to grow quickly but sustainably. Fertilizer mixes should be high in nitrogen, low to medium in phosphorus, and high in potassium. During this stage, the nitrogen will help fuel the leaf and stem growth, while the potassium helps the roots to become strong and wide-reaching.

The final stage in a plant’s life cycle is the flowering/fruiting stage. Flowers will bloom and fruits and vegetables will develop their fruit. Leafy green growth is much less important during this phase, so nitrogen levels can be lower. Instead, flowering plants need higher percentages of phosphorus and potassium. Plants that never flower and remain leafy throughout their entire lives, such as grass, will only really require nitrogen in large amounts.

What are Fertilizers?

A lawn spreader distributing seed and nutrients

Fertilizers are an essential garden item when it comes to protecting the health of your plants. The purpose of fertilizers are to provide nutrients and help plants grow. However, there are two main types of fertilizers, chemical/synthetic and organic, that you can choose for your lawn.

Chemical/Synthetic Fertilizers and Pesticides

For the past few decades, chemical fertilizers have been all the rage with homeowners. They provide plants with a set balance of nutrients that they need to grow quickly. Unfortunately, most fertilizers of this type tend to be acidic, are not safe for use around kids and pets and actually do more harm than good over time.

Pesticides also fall into these two same categories. Approximately 70 million pounds of pesticides are used each year by homeowners whether it be for their lawn or garden. Pesticides are useful tools when keeping a garden healthy since they rid plants of harmful insects but they can also harm beneficial bugs, so make sure to use with care.

It is important to know the difference between chemical and organic fertilizers so you can treat your garden to long-term health and stability instead of short-term growth and long-term damage.

Organic Fertilizers

Organic fertilizers treat both the plant and the soil to not only help plants grow but to nourish the soil so plants can grow sustainably. Most organic fertilizers are formulated with naturally-derived ingredients including cornmeal, soybeans, etc. that do not shock plants or add harmful chemicals to the soil.

Keeping your garden healthy for longer is every gardener’s goal. By using organic fertilizers, as opposed to synthetic, you can reduce the potential pollution to the environment and enjoy the long-term benefits going organic can provide. Protect your garden with the knowledge you need to choose the right fertilizer with this helpful comparison chart.

When to Fertilize Your Garden

Chemical Fertilizers

Pros and Cons of Using Chemical Fertilizers
Cons Pros
Contains high acid content. Can burn skin and negatively impact soil fertility Rich in 3 essential nutrients needed to grow healthy plants
Short-term fix Inexpensive
Artificially prepared Plants grow quickly
Treats the plant not the soil
Kills beneficial bugs
Strips soil of nutrients and weakens grass
Can be harmful to pets
Toxic runoff

Providing nutrients to your garden is an essential step. Providing them at the right times is just as important to ensure your plants are healthy and have access to the right nutrients as soon as they need them.

Most garden plants become dormant in the winter and may appear dull in color or are surviving solely from their roots beneath the surface. As spring rolls around, plants start to grow and begin their life cycles all over again. It is best to wait until after the last frost in your area, but fertilizing in the spring gives your plants a much needed nutrient boost to grow to their full potential.

Food producing crops will need a well-balanced blend of nutrients throughout the growing season. Start in the spring and provide more nitrogen when they begin to actively grow, more phosphorus when they start to flower, and potassium as they finish fruiting. Many outdoor garden plants will benefit from a slow-release fertilizer that gradually provides nutrients throughout the season.

If you fertilize your lawn several times a year, it may be easier to fertilize your lawn and garden at the same time. Make sure you are using the proper blend of nutrients for each plant. It is best to fertilize outdoor plants around Memorial Day, Labor Day, and in the fall before the first frost.

Fertilizing before an upcoming period of rain can be very beneficial. The rain will activate the fertilizer and this will also help work the fertilizer into the soil where nutrients can be absorbed more efficiently.

Indoor gardens or potted plants should be fertilized monthly unless otherwise stated on their labels. Keep an eye out for signs of malnutrition so you can get ahead of any nutrient problems before they turn into a major issue.

How to Fertilize Your Garden

There are many methods of fertilizing, ranging from hand spreading to liquid sprays. Here are a few of the most common methods to help you choose the best option for your garden

A soil tester

First and foremost, you need to conduct a soil test. This will give you an indication of pH and which nutrients your soil already has in abundance and which ones it is lacking. By doing this simple task, you can save yourself lots of time, and money, by knowing which fertilizer NPK balance would benefit your garden the most.

Depending on what types of plants are growing in your garden there are many different estimates of how much fertilizer you should spread. Woody plants typically need 3 pounds of nitrogen per 1,000 feet while perennials need only 1 pound per 1,000 feet. Always follow the instructions found on the label of the fertilizer bag. Every fertilizer is formulated differently so make sure to follow the directions as closely as possible to achieve outstanding results.

Watering after you fertilize is critical. This allows the fertilizer to activate and immediately start to provide nutrients to the soil and plant. However, time of day can matter as well. Hydrating your plants in the heat of mid-day can be thwarted by excess evaporation. Watering your garden in the cooler parts of the day as well as after fertilizing will help prevent root burn and will help keep the water in the soil where it is needed.

Four Methods of Fertilizing

There are many different ways of fertilizing that range in difficulty and complexity. These methods include broadcast before planting, row applications, starter solutions, and side dressing.

Broadcast fertilizing focuses on spreading the correct amount of fertilizer evenly over a garden before planting begins. Oftentimes, the fertilizer is mixed in with the soil for the best results and usually causes the least amount of damage to plants.

Row applications involve applying a fertilizer in a strip alongside a row where a garden will be planted. The fertilizer is applied before planting and gardeners must be careful to keep the roots away from the fertilizer since it can sometimes kill plants.

Starter applications are used only for transplants. All you have to do is mix approximately two tablespoons of garden fertilizer with 1 gallon of water and mix well. Pour one cup of this solution into each hole and let it soak in completely before transplanting.

Side dressing is a fancy term for applying fertilizer to growing plants. This particularly helps plants that live in sandy soil or experience a lot of rain. Soils facing these conditions may have less nutrients available to them than in other conditions. This method is also relatively simple. Spread the fertilizer evenly in the soil around plants and water it into the soil.

Foliar Feeding

pump spray bottle spraying flowers

Foliar feeding applies a fertilizer directly to a plants’ leaves. While this is in no way a substitute for actual soil, it can help give your garden an extra boost of nutrients especially if your plants are facing a nutrient deficiency. Plants get most of their nutrients through their roots but they can actually absorb nutrients faster through their leaves, so applying that boost of nutrients to their foliage can be very beneficial. Keep in mind that healthy soil should be your primary concern to prevent future nutrient deficiencies.

Foliar sprays tend to be less concentrated than regular fertilizers and common foliar sprays include compost teas, herbal teas, and fish emulsions. For the best results, apply in the cooler hours during the morning to prevent evaporation or possible leaf burning. Spray the fertilizer until the leaves are lightly dripping and don’t forget to spray underneath the leaves as well. You can even place a small amount of insecticidal soap or horticultural oil to the plants before applying the spray to ensure it sticks to the leaves more efficiently.

pH and Why it Matters

Think back to your middle or high school science classes. Do you remember learning about pH and thought when in the world am I ever going to use this? Creating a thriving garden relies heavily on science, especially when it comes to soil health.

The pH Scale

Potential for hydrogen (pH) is a useful measurement that provides you with information on whether a substance is acidic or alkaline. pH is measured on a scale ranging from 0 to 14 with 0 being extremely acidic and 14 being extremely alkaline. Water is right in the middle with a pH around 7.

Plants will vary on what pH they find most hospitable. Make sure to read the labels on plants when buying them so you can adjust the soil and set your garden up for success. Keep in mind that most fertilizers will change the pH levels in soil slightly so you will need to test your soil to know how to balance the pH.

5 Things to Know from Gardening Experts

  • Fertilizer is Not Plant Food – Plants make their own food through the process of photosynthesis. Fertilizer just provides extra nutrients the plant needs to keep this process running smoothly. Think of fertilizers more as vitamins for your plants instead of a meal.
  • Not All Plants Need Fertilizer – If your soil is rich and healthy, you won’t need to fertilize. Your soil will provide everything a plant needs without having the extra expense or making the extra effort.
  • Less is More – Plants can only use the nutrients they need. If plants start to absorb more than is necessary, they can become malformed. It may take some time to find that perfect balance, but practicing moderation will ultimately lead to a healthier garden.
  • Plants Want It Slow – Slow-releasing fertilizers give plants a boost of nutrients over time. A sudden burst of nutrients can shock a plant and lead to problems later. Promoting sustainable growth should always be a gardener’s goal.
  • Spend Less Money Over Time – While organic fertilizers do require more money initially, they create a healthy environment that will eventually need less fertilizer. This means less money spent over time and more money to spend wherever you choose.

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