Fertilizers can seem like a complex science, but we’ve broken down all the basics to make it easy to understand!
Fertilizer is necessary for keeping your garden and landscape plants healthy and properly functioning. Everything from moisture uptake, root spread, leaf and flower production, and fruiting rely on the nutrients contained in fertilizers. Since plants draw up these nutrients from their soil, that soil gets depleted over time, and the nutrient supply needs to be topped up. However, proper fertilizer application is essential, and you need to be mindful of the type of formula you choose for all your different landscape plants.
How to Properly Apply Fertilizer Across the Landscape
The most important thing to do when applying fertilizer is to read the package directions carefully! Different formulas have different levels of concentration and may be absorbed differently. For example, slow-release granular formulas for the landscape should be scattered across the lawn in a controlled manner with a spreader.
Slow-release granular formulas for the garden are different. You can sprinkle them across the soil surface manually, but you need to make sure they don’t touch the foliage of your plants, or else they might get burned. Water-soluble formulas work faster and provide an instant nutrient boost, but you must dilute them in the right amount of water, according to package instructions.
When you’re fertilizing landscape plants like trees and shrubs, you’ll want to spread the formula across the surface of your soil at a diameter of 1.5X the width of your plant’s crown. So, if your shrub is 5 feet wide, you’ll want to cover 7.5 feet of ground, which is a 3.75-foot radius around your plant.
The Difference Between Fertilizers
Three main nutrients make up plant fertilizer: Nitrogen (N), Phosphorus (P), and Potassium (K); this makes up the NPK ratio, which is the three-digit number on the front of the bag. Other nutrients like magnesium and calcium may be present, but NPK are the most important. Different landscape plants need different amounts of certain nutrients for the best possible growth, so it’s essential to pay attention to what you’re buying.
Nitrogen (N) is necessary for good foliage production, phosphorus (P) is necessary for flowering, fruiting, and root growth, and potassium (K) is essential for overall plant health and basic functions like moisture uptake. If you give a flowering plant a formula with lots of nitrogen and far less phosphorus, you will get a super leafy plant with very few blooms. If you’re growing a leafy landscape plant that doesn’t flower, something with low nitrogen won’t produce good results.
All-purpose fertilizers have a balanced ratio of nitrogen, phosphorus, and potassium. They can be used as a one-size-fits-all solution if you want to keep your landscape maintenance as simple as possible, but for best results, you should use a formula specifically tailored to your chosen plants.
Fertilizer for Landscape Plants Like Trees and Shrubs
The best fertilizer for landscape plants like trees and shrubs is something with a 2-1-1 ratio—this allows for lush foliage growth while still helping produce flowers and healthy roots. Fruit trees—particularly citrus trees—need extra nutrients to keep them healthy, like manganese, iron, copper, and zinc. Fertilizers made especially for fruit trees will help them produce more flowers and fruit while helping prevent diseases and issues caused by nutrient deficiencies.
Fertilizer for Flower Gardens
All-purpose, balanced fertilizers usually work quite well for garden flowers. If you’re growing them in container gardens, you may need to fertilize more frequently because the available nutrient reserves are much more limited than in a garden bed. There’s no need to grab a formula with a super high phosphorus level—that won’t help your plant produce more flowers, and it can negatively affect the soil and contaminate groundwater runoff.
Fertilizer for Vegetable Gardens
Look for a formula that’s approved for use in vegetable gardens. You’re going to be eating these plants, after all! You’ll want to use something safe to use on plants you intend to consume. We like the Organic fertilizers from Espoma.
Fertilizer for Lawns
One of the best fertilizers to use all across the landscape in spring is a weed and feed. These formulas have pre-emergent herbicide, so they help nourish the soil and feed your grass while preventing weeds from germinating. You should only use these formulas early in the season before weeds have begun to sprout.
After that, you can use a formula with an NPK ratio of 10-5-5; this will allow the grass in your landscape to direct most of its energy to produce lush, green foliage that’s healthy and strong while still devoting some energy to its roots.
On the hunt for fertilizer for sale in Iowa? Wallace’s has an incredible selection of synthetic and organic formulas for all your landscape plants, so visit us soon to stock up in time for summer!