What You Need to Know About Fertilizer
If you want to grow healthy plants, you need to know what to feed them. Learn all about the benefits of fertilizer, what to look for in a fertilizer blend, and the best strategies for applying it to your plants.
When you’re looking to grow the healthiest plants possible, sometimes they need a boost. Fertilizers promise to give you long-lasting blooms, bigger harvests, and more productive plants. But, knowing where to start with fertilizer can be overwhelming when you’re first getting started.
Here’s a closer look at how fertilizers work and what you need to know to choose one for your garden.
What Is Fertilizer?
Plants pull everything they need to thrive out of the soil through their roots. Over time, they absorb such a large concentration of nutrients that the ground becomes depleted. Adding fertilizer to your garden replenishes these nutrients so that plants continue to grow well.
Put another way, adding fertilizer to a garden is like putting money back in the bank after draining your savings account.
How Does Fertilizer Work?
Though fertilizers can contain dozens of compounds that promote plant growth, three primary nutrients make up almost the entire formula: nitrogen, phosphorus, and potassium. On a soil bag, you’ll see these represented as N-P-K, or as numbers in place of each letter to represent the ratio of each nutrient within it.
Here’s why each nutrient is important:
Nitrogen
As one of the most common elements in nature, nitrogen is critical to all forms of life. Homemade compost and animal manures contain lots of nitrogen. This nutrient is responsible for giving plants vibrant green foliage, and too little leads to stunted leaves. However, excessive nitrogen can be just as problematic, as it makes plants prioritize leaf and stem growth at the expense of producing flowers or fruit.
Phosphorus
This nutrient is critical for root growth and bloom formation, making it an essential component for all fruiting plants. A lack of phosphorus will lead to stunted tomatoes or squash plants that never develop blossoms. Good sources of phosphorus include bone meal and rock phosphate.
Potassium
Potassium promotes photosynthesis and helps the interconnected systems within plants function together. Without it, plants look weak and spindly. Wood ash can restore potassium levels, though too much can burn plants.
Other Key Plant Nutrients
Beyond these three main components, plants need smaller quantities of other critical nutrients.
- Calcium: Improves soil structure, binds particles together, helps neutralize toxic materials.
- Magnesium: Essential for plants to process sunlight.
- Sulfur: The primary component of many proteins.
- Boron: Promotes cell division for plant growth.
- Copper: Activates plant enzymes that promote plant synthesis and aid respiration.
- Iron: Helps synthesize chlorophyll and produces green pigments.
- Molybdenum: Promotes healthy leaf formation and prevents a buildup of nitrates.
- Zinc: Helps plants withstand cold temperatures and converts starches to sugars.
- Chlorine: Aids photosynthesis and helps take in and release gasses like oxygen and carbon dioxide.
- Manganese: Supports healthy plant cell functioning.
An all-purpose 5-5-5 fertilizer will typically provide an ideal ratio of nutrients plants need to thrive. If your soil has specific deficiencies, you will need a specialized formula that can address them.
Organic vs. Synthetic—Does It Matter?
One primary decision every gardener needs to make is whether to use synthetic or organic fertilizer.
Synthetic Fertilizers
Synthetic fertilizers are made through a chemical process that typically uses oil and other nonrenewable resources. Most synthetic fertilizers are water-soluble and prioritize the three main nutrients (NPK), which means plants can take them in fast and show improvements quickly.
However, these fertilizers tend to be deficient in other essential nutrients, potentially leading to problems for plant health over the long term.
Organic Fertilizers
In contrast, organic fertilizers come from naturally occurring materials that may include mineral deposits, bone meal, fish emulsions, or composted manure. In most cases, organic fertilizers are not water-soluble, which means they release their nutrients into the soil over time.
Ideally, you want to apply them in the fall so that they can break down over the winter and be available for your plants by spring.
Beyond feeding plants, organic fertilizers improve the soil’s structure and create habitat space for beneficial soil microorganisms that aid plant growth. They also tend to be more complex than synthetic options and will provide plants with all the necessary secondary plant nutrients.
Which Is Best? A Summary
So, in short, synthetic fertilizers are easy to use and offer fast results but often don’t support long-term plant health. Organic amendments work more slowly, but they promote overall soil health and give plants a better balance of essential nutrients.
Some gardeners may find a blend of both works best. Consider using organic fertilizers in the fall to enrich your soil and promote microbial life, and apply synthetic fertilizers as needed over the growing season to keep things vibrant.
Understanding Different Fertilizer Applications Methods
Fertilizers come in multiple forms depending on your preferred method for feeding your plants. Here are some to be aware of.
Dry Fertilizer: As the easiest type of fertilizer to apply, dry fertilizers can be scattered by hand (wear gloves!) or dispersed over a larger area with a spreader. You can add more around the base of plants over the growing season to aid their growth.
Slow Release: This fertilizer typically comes with a coating that breaks down over time after heat and water exposure to slowly release its nutrients into the soil. This makes it possible to fertilize without fear of burning your plants. To use, sprinkle directly into the ground.
Liquid: Plants can absorb nutrients up to 20 times more efficiently through their leaves than the roots. For this reason, liquid fertilizers are usually sprayed directly onto plant leaves, so it absorbs the nutrients directly. Any that drips into the soil will get taken in by the roots. This provides plants with a quick nutrient boost and is one of the best ways to revive fading plants. As liquid fertilizers are potent, you must take care to dilute them according to the manufacturer’s instructions.
Choosing the right fertilizer for your garden is an important decision. Take time to research what’s best for your plants, and your garden will thrive from your effort.