Skip to main content

It’s Autumn now, and if you care for a lawn or garden, it’s time to start thinking ahead to the joys of Spring. Whether or not you are walking through a lush field of green and flowering plants in Spring, or brown patches of weeds, depends closely on the decisions you make today, in Autumn. Now is the time to fertilize for the Spring, in order to help the roots grow before the harshness of Winter sets in. Strong roots mean a healthy plant, and an increased resistance to disease and drought. Strong roots mean green, leafy plants in the Spring, with lots of beautiful budding flowers. Healthy plants are like the ant in Aesop’s fable “The Ant and the Grasshopper.” You remember the story right? The ant spent Summer and Autumn storing resources, while the grasshopper lazed about. When the Winter came, the ant was warm in house and well-fed, while the grasshopper starved and froze during the winter looking for food.

So Fall is not too late to fertilize your garden or lawn. In fact, fertilizers should never be spread until well after Summer has ended, when temperatures are above 90 degrees, to prevent nutrient burn. Now you may be wondering what kind of fertilizer you should use. First of all, know that a proper fertilizer guide could not possibly address each and everybody’s particular situation. This guide is meant to be as general as possible so as to be of assistance to anybody, no matter where they are or what they are growing.


N-P-K stands for ‘Nitrogen’ ‘Phosphorus’ and ‘Potassium (the chemical symbol for Potassium is “k”).’ Understand these three elements, and you will be well on the way towards choosing the proper fertilizer for this season!


This element underlies many important structures, genetic compounds, and metabolic enzymes in plant cells. It’s the major component of chlorophyll, which plants use to convert sunlight energy into sugars from water and carbon dioxide (photosynthesis). It a major component of proteins, some of which function to provide the plant structural support, while others act as enzymes, acting as biochemical catalyts that enable the plant to grow. Nitrogen is energy itself as well, being a necessary part of the energy-transfer compounds such as ATP (adenosine triphosphate), which allows cells to conserve, as well as use energy present in the plant’s metabolism.

Plants that have adequate nitrogren grow rapidly and are lush, usually producing copious amounts of succulent, green foliage. You can tell if your plants are deficient in nitrogen because your plant will appear sickly. It will be smaller and develop slower because it will not have the nitrogen necessary to manufacture neither a robust, hardened cell-wall structure, nor a healthy internal chemistry. The leaves will be pale green or yellowish, and it will lack adequate chlorophyll. Older leaves become necrotic and die as the plants moves scarce nitrogen from older leaves to younger, more vital ones.

Now don’t go out today and start drowning your plants in nitrogen. Too much nitrogen can have a detrimental effect as well. The plant can grow so rapidly that they develop protoplasm faster than they can develop hardened cell structures that support the plant. These types of plants are often rather weak and are likely to suffer some sort of breaking or mechanical injury.


This element is very important for Fall fertilizing. The reason is this: It is hard to correctly diagnose phosphorus deficiencies until Spring season when the crops develop and begin to produce seeds. Phosphorus is vital to the internal chemistry and energy conversion capabilities of the plant. It is a vital part of DNA, the genetic code within every living thing, as well as RNA, which is like a computer program who’s job it is to read the DNA code and build the necessary proteins and other types of compounds to use in the plant’s structure, seed yield, and genetic transfer. The bonds that link the structures of both of DNA and RNA are bonds made of phosphorus.

It is an important component of ATP, which is the energy unit of plants. Thus, it is essential for the health and vigor of all plants. A plant with healthy phosphorus levels will have stimulated root development, increased stem strength, brighter, healthier flowers, seed production, earlier crop maturity, and increased resistance to plant diseases.

It it worth noting as well that a plant’s response to phosphorus can be detrimentally affected by insufficient levels of other nutrients. Balanced nutrition for your plants is key!


This element is not a constituent of any plant structures or compounds. It plays many important biochemical regulatory roles in the plant such as:


-Translocation of photosynthesis

-Protein synthesis

-Control of ionic balance

-Regulation of plant stomata and water use

-Activation of plant enzymes

And many, many other processes! It is known to activate at least sixty enzymes involved in a plant’s internal biochemistry. Plants that don’t have enough potassium are less resistant to drought, excess water, and high and low temperatures. They are less resistant to pests, diseases, and attacks by nefarious nematodes. It is a quality nutrient; it affects more subjective, aesthetic aspects of plants, such as size, shape, color, taste, fiber quality, and other quality measurements.

Now that you understand the three most important components of any fertilizer, you are ready to diagnose your own particular needs for your own lawn or garden. Fertilizers will always come with 3 numbers on the box (they are required by law to do this) For instance, if you buy fertilizer and somewhere on the container you will see three numbers like this: 8-5-5. These numbers mean that 8% of the total weight of the package is nitrogen, 5% is phosphorus, and 5% is potassium. Please know that there are other nutrients that may be present as well. Please do research, and read what extra ingredients are present in the fertilizer. Soils such as Fox Farm uses beneficial microorganisms, pre-digested enzymes, vitamins and amino acids that have other functional values than N-P-K does. However, N-P-K is the true foundation of any good fertilizer, so that makes the understanding of these elements any budding gardener’s top priority! Learn these elements and how to implement them in your fall fertilizing schedule, and your plants will happy!

Generally, a good rule of thumb is to increase nitrogen when growing. When flowering, increase phosphorus and potassium. However, you’re going to want to take the time to understand your own particular situation, for your needs may differ from what is generally true.