How to Fertilize Your Lawn in Southern Florida

Some of the direst dilemmas people see with administering their own lawn care programs come from fertilization.  It is a very sensitive issue, with a lot of consideration to make to ensure you are do the proper treatment.  Not only can you waste your money on expensive fertilizer if you go wrong, but you can completely destroy your lawn…all in the name of trying to make it nicer.

When spring time hits Martin County, one of the most tempting things is to go outside and fertilize your lawn in hopes promoting a greener, more lush lawn, quicker. This is a good idea, but care must be taken.  In the spring, it is best to apply a high nitrogen fertilizer (nitrogen promotes growth).  You have to be really careful though, because fertilizer that is high in nitrogen not only can increase thatch problems (the layer of dead grass that blocks nutrients from getting to the roots and a lot of pests are attracted to thus infecting your lawn), but you can also literally “burn” your grass…nitrogen is potent stuff, and not only can too much damage your lawn, but you should always stay off your lawn for 24-48 hours (kids and pets especially) after applying fertilizer.

You also want to be very careful of the “Weed and Feed” types of products that are sold at big box stores like Home Depot or Lowes.  These are fertilizers that try to kill two birds with one stone, doubling as both a fertilizer, but also a pre-emergent herbicide to kill weeds.  The whole issue of herbicides is even more complex than fertilization, and the State of Florida requires you be licensed to apply it.  If you are going to try your luck with these weed and feed products, make sure that you read every inch of the product you are buying.  These products are very powerful and developed to kill weeds and prevent their future growth…they do so by targeting certain forms of life, and sometimes you might buy the stuff that is intended for Bahia Grass (kills everything but your Bahia). If you buy this and apply it to your Saint Augustine lawn…you won’t have a lawn in a couple of weeks.  Another reason I don’t advise trying your luck with “Weed and Feed” type products is because of the runoff issues we have when it rains and these herbicides get into areas they shouldn’t, affecting habitats in Martin County. It is better to simply spot-apply weed killers to the areas that need them.  In general, it is always better to go with commercial quality fertilizers like the ones The Mednick Landscape Company uses.  When you buy your fertilizer at a big box store from one of the residentially marketed brands, you are paying for their advertising and marketing fees, and a fertilizer that has much more filler than the commercial alternatives.  It is like paying for a steak but getting a hamburger.

The Proper Nutrients for Your Grass

Fertilizers generally consist of three main ingredients: Nitrogen, Phosphorus, and Potassium (you see these labeled on fertilizers as #-#-# with respect to the percentage of that particular fertilizers make-up).

Nitrogen is arguably the most important nutrient for grass.  Chlorophyll in your grass requires nitrogen and it is what facilitates the lawns growth (like proteins for humans) and promotes its deep green color.  

Phosphorus is beneficial to the grasses energy transfer systems but is needed in much less quantity.  In fact, soils in Palm City, Stuart, Jensen Beach, and Hobe Sound tend to be very high in phosphorus naturally and take care of most of their lawns needs.  Unless you have a brand new lawn, the addition of phosphorus can largely be overlooked in Martin County.

Potassium is very important and your fertilizer should have a good amount of it.  Potassium is responsible for the development of the grasses cell walls and its ability to withstand stress, disease, pests, drought, and high temperatures.  It plays a similar role to the white blood cells in humans as the bodies defense and immunity.

It is best to try and find a fertilizer with a slow release of nitrogen.  A lot of big box products go for quick results and have extremely soluble nitrogen in their products…this puts a smile on your face quickly, as the lawn becomes green in a matter of weeks (or burns from too much nitrogen).  Slow release nitrogen continues to work for months, building a healthier lawn with each rain/watering.  (Another consideration to make is that when you elect to keep your grass clippings on your lawn, you are actually reducing your need to fertilize by up to 25 percent because you are returning the clippings nutrients to your soil).

Southern grasses like those throughout Stuart, Palm City, Jensen Beach and Hobe Sound (Bahia, Bermuda, Saint Augustine, Floratam) really take off in the summer months when sunlight is abundant and so is rain.  It is recommended to give your lawn a jump start in the springtime, but then to apply its main fertilizer application come June.  The spring application should be high in nitrogen, with the early summer application should have more even levels of nitrogen and potassium.  This promotes both a healthy root system that is disease and stress resistant, as well as a healthy, lush, deep green lawn, without too much leaf growth.