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Rebecca Small - June 09 2020

Beginners Guide to Fertilizer

Finding the right fertilizer for your plant can seem overwhelming when you’re new to gardening! Here is Parkway’s simple guide to understanding fertilizers and choosing the right one to meet the needs of your plant. 

(N)nitrogen - (P)phosphorus - (K)potassium 

To start off, you need to know the three main nutrients your plant requires. These are nitrogen, phosphorus and potassium, often abbreviated to N-P-K. They are represented on a fertilizer package as three variable numbers, always in the same order (ex 8-12-16). The numbers indicate the percentage of each nutrient present in that fertilizer. An 8-12-16 fertilizer has 8% nitrogen, 12% phosphorus, and 16% potassium. This fertilizer will only have 36% active nutrients, the remaining 64% is made up of fillers which help the product retain its proper consistency and disperse its nutrients properly. 

Now that you know what the numbers represent you need to know how they help your plant. Nitrogen promotes growth and vibrant green leaves. It’s also a great choice for achieving a greener lawn. Phosphorus promotes healthy root growth as well as blooms and fruit, making it essential for flowers and fruiting vegetables like peppers and tomatoes. Potassium promotes overall plant health and helps your plant withstand stress. An easy way to remember how each nutrient helps is the phrase ‘Up, down, and all around.’ Up, nitrogen promotes above-ground growth. Down, phosphorus promotes root growth. All around, potassium promotes general plant health. 

When buying a fertilizer you will notice that they are typically liquid, water-soluble or slow release. Liquid and water-soluble powder fertilizers must be mixed with the correct amount of water before use. These fertilizers have the benefit of being fast acting as they reach the plant as soon as the roots begin taking up the fertilized water. One drawback is that they need to be applied frequently, potentially every time you water your plant. You also need to take care that you never use fertilized water on a very dry plant as this can burn the roots and cause damage. Slow-release fertilizer needs to be applied less often, as one feeding can last weeks or even months depending on the fertilizer. It is less fast-acting as it slowly breaks down and releases its nutrients over time. 

At this point, you’re probably wondering what plants to fertilize and when? When planting a new tree or shrub we always recommend transplant fertilizer. This will help your plant set out new roots and reduce transplant shock. For trees, shrubs, and perennials that are already established you don’t want to fertilize them too early in the spring. Fertilizer will promote new growth that could be damaged by a sudden cold snap. Wait until the weather is consistently warm before fertilizing. Do not fertilize these plants any later than midsummer as they need time to harden off any new growth before the winter. Annuals should be fertilized throughout the season. To keep patio pots and hanging baskets blooming all summer you need to fertilize them regularly with slow release or liquid fertilizer. 

Now that you’ve learned the basics you can select a fertilizer with confidence, knowing which one can help you achieve your desired results. Whether you’re looking to promote green, lush leaves, abundant fruit or prolific flowers, finding the correct fertilizer should be much easier!