Fertilization – By Mark Govan, Host “Florida Gardening”

Fertilization of our ornamental landscape plants and turf grasses are very important to root formation and the disease fighting characteristics of these plants. When plants are stressed due to irrigation problems such as drought or insect infestations, their root systems start to shut down causing further damage. Proper fertilization can enhance the ability of plants to form additional roots which grow deeper into the ground. This allows additional water and nutrients to be absorbed by the roots protecting the plants from occasional drought or insect problems. Applying the right type of fertilizer and the proper nutrients can help our ornamental plants and lawns survive these problems. This week I am going to touch on the importance of using the proper type’s of fertilizer and when to make these applications. Let’s get started.

If you have not started your fertilizer campaign yet, you need to know you are running out of time. Because the State of Florida and many local communities have adopted fertilizer restrictions and blackout periods of when you can purchase or apply fertilizers, then you need to start now. The City of Tampa, Pinellas County, Manatee County, and Sarasota County among many others all have restrictions of what type of fertilizer you can apply, where you can apply the fertilizer, and how much fertilizer you can apply. If this is the first time you are hearing of this then I am sorry to inform you that the blackout period for all purchases of fertilizer will begin in two weeks from the day you receive this article or June 1st.

The one commonality of all these individual restrictions is this fertilizer blackout period runs from June 1st through September 30th. During this time you will not be able to purchase or apply fertilizers to plants or lawns. There are a few exclusions to this rule such as vegetable gardens. Unfortunately, many of us gardeners call this blackout period the growing season and rightfully so. This is the time most of our plants and lawns are actively growing and require additional elements to continue thriving. As our plants break down and utilize elements in the soil to produce roots and leaves, wise gardeners replace these elements by adding additional fertilizer. Not only does this make the plant respond by growing thicker greener foliage but the plants also put down more roots. These additional roots and nutrients also help the plants natural ability to resist the infection of fungal diseases and insects.

If you have not hired a professional lawn care company to care for your ornamental plants or lawns, then you need to fertilize your plants now. Ornamental plants and flowering landscape plants require nutrients that typical lawn fertilizers do not contain. This is the reason you will need two different types of fertilizers, one for your plants and one for your lawns. Because most of our ornamental plants produce blossoms, you need to apply a blooming or flowering type of fertilizer that contains Phosphorous. Phosphorous is represented by the middle number on a bag of fertilizer such as an 8-10-10. The main objective of this element is to produce blooms or fruit on our plants. Because our turf grasses do not bloom or produce fruit, this element is unnecessary when fertilizing your lawn and most lawn fertilizers have a zero in the analysis numbers on the fertilizer bag such as a 16-0-10.

Ornamental fertilizers come in many different analyses. Do not let the numbers on the bags concern you as some have higher or lower concentrations of certain elements. Also, some are granular and some are liquid. Granular fertilizers are the preferred choice as these types of fertilizers are longer lasting. Liquid fertilizers are generally quick release and must be used very frequently. Slow release granular fertilizers tend to break down slowly and feed your plants over a period of months. Some slow release fertilizers can last for up to a year however, these types of fertilizers are very expensive and I do not recommend them for you unless you are a professional applicator. When I say slow release fertilizer, I am talking about the nitrogen content of the fertilizer or the first number you see on a bag of fertilizer. Nitrogen sources are broken down by the source of where the nitrogen is derived from.

The next time you purchase a bag of fertilizer look at the label and you will see where the nitrogen source is derived from. Nitrate Nitrogen, Urea Nitrogen, and Ammonium Nitrate are all quick release type fertilizers but most fertilizers will have some of these nitrogen sources in the bag. Some quick release sources of nitrogen are good because they will be released quickly giving your plants a quick boost of ready to use nitrogen. However, if the total nitrogen source in the bag is only from these forms of nitrogen, then this is a quick release fertilizer and you will have the possibility of burning your plants.

The fertilizer you purchase for your plants or your lawn should have at least four units of slow release nitrogen or water insoluble nitrogen. This will be stated clearly on the bag. Look for nitrogen sources derived from Sulfur Coated Urea, Methylene Urea, Nutralene, and Isobuthylene Diurea. Fertilizers derived from these sources will cost more but will last much longer than your generic fertilizers and will not burn your plants. You will also be able to wait much longer in-between applications as these products will last eight to twelve weeks or longer. When these products are applied to your plants or lawn they break down very slowly giving your plants the nutrients they need over an extended period of time. Since we can not apply additional fertilizer from June through September, these products will be able to spoon feed your plants over several months.

Most garden centers carry granular Osmacote or Dynamite fertilizers which are slow release. There are other varieties but you will need to take the time and read the label so you can make an educated choice. Apply at least four to five pounds of fertilizer for every one hundred square feet of ornamental bed space you have. I like to use a rotary hand held spreader which you can find at your local garden centers to apply my fertilizer. One hopper full equals about five pounds so all you have to do is figure out how much bed space you have. A ten by ten area will need one hopper full. If you are fertilizing a hedge, make sure you do both sides of the hedge. Try not to direct the fertilizer over the top of the plant; rather you should fertilize under the foliage out to the drip line of the plant and beyond. Granular fertilizer placed directly over the foliage may burn the tender new growth. Liquid fertilizers and micro-element nutritional fertilizers may be applied directly over the plant at one-half strength every two to three weeks.

Turf Grass should be fertilized now and again in October with a 16-0-10 analysis. Most residential lawns will require at least fifty pounds of a slow release fertilizer. I know this seems like a lot but this is what your lawn requires if you have five thousand square feet of turf grass. When making your application, you should use a rotary type spreader and each pass you make over the lawn should be approximately three feet apart. This will give you the fifty percent overlap you need and will help prevent streaking. Make sure you square off the lawn and make straight passes to ensure proper application. Do not round off corners. Box off corners to prevent streaking. If a tree is in the way of a pass, stop at the tree and go around it then start again on the other side of the tree in the same line you were walking.

Be sure to sweep up any spilled fertilizer off sidewalks and driveways. Fertilizer left on paved surfaces can stain and are subject to being washed away during a thunderstorm. Fertilizer misuse has been blamed for algae blooms and water quality issues if allowed to get into storm water drains which empty into the Bay or Gulf. Always wash out your spreader with water and be sure to clean your hands following application.

Selecting the right type and applying the right amount of fertilizer is very important to the health and beauty of your plants and lawn. Use slow release forms of nitrogen fertilizers to spoon feed your plants over the summer and through the blackout period. Be diligent and use the right amount of fertilizer as your plants are constantly growing and need to be fed regularly. I hope I have given you a few recommendations that you can use to select the right type of fertilizer for your plants and lawn. Enjoy your landscape and remember, without our plants we would not be here.

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