Fertilizers can be confusing. This guide will explain what 16-16-16 is and how to use it.
What Is 16-16-16 Fertilizer?
Triple 16 contains sixteen percent nitrogen, sixteen percent phosphorus, and sixteen percent potassium. It is a balanced fertilizer because all the numbers are the same.
Briefly, nitrogen is used everywhere in the plant to grow. Phosphorus is used to trigger blooms and set fruit. Potassium works to build overall vigor and strong roots. The numbers on the front of the fertilizer bag are explained in more detail in this article.
What Is 16-16-16 Fertilizer Used For?
Triple 16 is used primarily as a starter fertilizer in the spring and for new lawns.
Why Use 16-16-16?
Triple 16 provides a high concentration of nutrients and can be found in slow-release varieties that last from early spring until the fall.
Types of Fertilizer
Fertilizer comes in several forms. Here is what they are and why each is used.
Liquid fertilizers are used in place of one watering. They work immediately but only last about two weeks before they need to be applied again. Some liquids are ready to use, and some are concentrates that must be mixed with water before use.
Water-soluble fertilizers are granules that dissolve completely in water. Once they are dissolved, they are used just like liquid fertilizers. They also have the same advantages and disadvantages.
Fertilizer for Hydroponics
Hydroponic fertilizers are added to the water solution that washes over the plant leaves to feed and water them. Either liquid or water-soluble fertilizer will work in hydroponic systems.
Granular Fertilizer is made of small granules that look like small rocks. It is usually mixed with at least half slow-release granules so that the Fertilizer lasts longer. Slow-release Fertilizer starts working in about a week and can last a long time. Fast-release granules work immediately and last one to two weeks. These are often mixed together so that some fertilizer reaches the plants immediately and some persists for much longer.
Organic Fertilizer is made of only organic ingredients. Certified organic Fertilizer only has ingredients on the OMRI list of approved materials for organic Fertilizer. In addition, the Fertilizer is submitted to a certifying agency, usually the USDA or Oregan Tilth in the United States, and approved for use in organic gardens.
When and How Do I Apply 16-16-16 Fertilizer?
Triple 16 is administered differently in different forms and to different plants. Here are some general guidelines. I always check the label before I use any fertilizer and follow the instructions there to avoid making my plants sick.
In general, triple 16 is too strong for most houseplants. I use 10-10-10 instead. I mix it according to the label directions because different concentrations use different amounts.
I use triple 16 in early spring on new flowers. I use two cups of 16-16-16 fertilizer per 100 square feet and broadcast it, then scratch the Fertilizer into the first two to three inches of soil. After the initial fertilization, I switch to 5-10-10. Triple 16 will trigger too much foliage and not enough flowers.
Existing Ornamental Plants
In the early spring, I use triple 16 to wake up my existing ornamentals in the garden. I use a granular fertilizer and spread two cups of 16-16-16 fertilizer per 100 square feet. I switch to 5-10-10 to bring on the blooms after the first fertilization.
Bulbs and Tubers
I don’t use triple 16 on bulbs and tubers. It is too strong and will burn them. Instead, I use 10-10-10.
I use triple 16 to fertilize the soil before planting my transplants and seeds. I spread two cups of 16-16-16 per 100 square feet. After the initial fertilization, I switch to more specialized fertilizers for cucumbers, tomatoes, pumpkins and squash, and other vegetables. Triple 16 is too strong to continue to use and often does not have the micronutrients vegetables need. It also has too much nitrogen for continued use.
Please consult my article if you want to fertilize your vegetable gardens.
Deciduous Ornamental Trees
Less than three inches in diameter at chest height, use ½ pound of 16-16-16 fertilizer per inch of trunk.
Over three inches in diameter at chest height, use 1-1.5 pounds of 16-16-16 fertilizer per inch of trunk.
I repeat the application six to eight weeks later and when the leaves drop in the fall.
Less than three inches in diameter, use ¼ pound of 16-16-16 fertilizer per inch of trunk.
Over three inches in diameter, use ½-¾ pounds of 16-16-16 fertilizer per inch of trunk.
I repeat the application in six to eight weeks and when the leaves start to fall off the deciduous trees.
Fruit and Nut Trees
For trees five years old and younger, I use ½ pound of 16-16-16 fertilizer per three feet of tree height when bud break occurs. I repeat the application when leaves drop in the fall.
For older trees, I use ¾ pound of 16-16-16 fertilizer per three feet of tree height when bud break occurs. Do not exceed 4.5 pounds of Fertilizer per tree. I repeat this fertilizer when the leaves drop in the fall.
I fertilize my citrus trees in early spring, then repeat every six weeks up to four times.
Trees up to three feet tall: 1 to 1½ tablespoons
Trees 3-8 feet: one cup
Trees over eight feet tall: two to four cups
Container citrus trees up to four feet tall: 1-11/2 tablespoons
Container trees over four feet tall: 1/3 cup
Established lawns: apply two cups per 200 square feet in early spring
New lawns: apply 2 ½ cups per 200 square feet before planting and scratch into the top three inches of soil.
I switch to nitrogen after the first fertilization because 16-16-16 has too much phosphorus and potassium for frequent use.
Scotts/Republic Accugreen (Drop)
Established Lawn 4,000 sq. ft. – 8
New Lawn 3,200 sq. ft. – 9
Scotts/Republic Speedy Green (Broadcast)
Established Lawn 4,000 sq. ft. – 7
New Lawn 3,200 sq. ft. – 8
Ferti-lome /Earthway Ev-N-Spred (Broadcast)
Established Lawn 4,000 sq. ft. – 18
New Lawn 3,200 sq. ft. – 20
Where Do I Buy 16-16-16 Fertilizer?
Triple 16 fertilizer is readily available from nurseries and from big box stores like Lowe’s, Amazon, and Walmart.
Top Brands for 16-16-16 Fertilizers
My top recommendations for Fertilizer are manufactured by these companies.
Maxsea/ Hawthorne Hydroponics, LLC
Maxsea is manufactured by Hawthorne Hydroponics, LLC. Founded in 1976, Hawthorne has partnered with Scotts Miracle-Gro recently for their research and development laboratories. Hawthorne sells everything you need to grow using hydroponic systems, including lighting, nutrients, growing media, fans, and filtration. Just add plants!
Lily Miller is a fertilizer line produced by Central Garden and Pet Co. Founded by Bill Brown in 1980 as Central Garden Supply, Central Garden and Pet Co. was incorporated in 1992. They are based in Walnut Creek, California. Central’s goal is to produce high-quality ingredients for everything around your home, including your lawn and ornamental plants.
Hi-Yield is owned by VPG, the same company that owns Ferti-lome. Hi-Yield was started in 1976 to enable retailers to compete with big box stores. Each distributor is part owner of the company. VPG was founded in 1968 to empower local retailers. VPG’s headquarters is in Bonham, Texas.
What Is the Best 16-16-16 Fertilizer?
Here are my picks for the best 16-16-16 Fertilizer. I did not find liquid or organic 16-16-16 fertilizer.
Maxsea HGC722255 All Purpose 16-16-16 Hydroponic Nutrient Fertilizer is my pick for the best water-soluble fertilizer. Developed for use in hydroponic solutions, this fertilizer is also good for ornamental plants. It is the one I would use on my houseplants if I used 16-16-16 on them. Maxsea provides sulfur, boron, copper, iron, manganese, molybdenum, and zinc in addition to nitrogen, phosphorous, and potassium. North American seaweed is included for important trace minerals and other things that benefit plants. Maxsea claims that this Fertilizer will promote vigorous, sturdy plants with distinct, dark, seaweed green foliage, quality blossoms, and abundant fruit and vegetables if used regularly. I like this fertilizer because it is easy to mix into water and use instead of water when watering my ornamental plants. The fast-acting fertilizer can make my plants greener in as little as twenty-four hours. I don’t use it on my vegetables because I prefer a slow-release fertilizer for them. Maxsea is pricey, with this 6-pound can $71.99 at Amazon. You may be able to find it cheaper at other retailers. Of course, one reason it is so expensive is the shipping. This product is not organic.
Maxsea HGC722255 All Purpose 16-16-16 Hydroponic Nutrient Fertilizer is easy to use. For my outdoor plants, I fertilize with it every seven to fourteen days. I mix one heaping tablespoon per gallon of water and drench the soil with ½ gallon of the solution. For my indoor plants, I use Maxsea instead of water at a concentration of one-half teaspoon per gallon of water. I don’t use this solution on my sensitive plants as it is too strong for them. If I am fertilizing a lot of plants in a flower bed, I mix one cup of Fertilizer with enough water to make one pint of the solution, put it in my hose end sprayer, and set the dial on one tablespoon for intermittent feeding or one teaspoon for feeding every time I water.
Hi-Yield (32351) Triple 16-16-16 Fertilizer is my pick for the best granular fertilizer. It is good for ornamental plants, vegetables, trees, and shrubs. Hi-Yield 16-16-16 is also useful to use before sodding or planting a new lawn. This fertilizer only contains nitrogen, phosphorus, potassium, and sulfur. It does not have any other nutrients. Hi-Yield 16-16-16 is a slow-release formula, so you do not have to fertilize as often as with Maxsea or Lily Miller 16-16-16. This is a good fertilizer to use in the early spring to wake up your ornamental plants, trees, and shrubs. It is also good to use before you plant vegetables or a new lawn. I would not use Hi-Yield 16-16-16 for established lawns because it has too much phosphorus and potassium for most grass. I also would use a different fertilizer for ongoing fertilization on ornamental plants and vegetables. Ornamental flowering plants need more phosphorus to encourage blooms. Vegetables need less nitrogen to keep from having all foliage and no vegetables. I would use Maxsea on my houseplants instead of this fertilizer. The liquid Maxsea solution is easier to use on houseplants.
For new lawns, the package recommends using 2 ½ cups for every 200 square feet or the whole 20-pound bag for 3200 square feet (about the area of a tennis court). The spreader settings are Scotts/Acugreen 9, Scotts/Republic Speedy Green 8, and Fertil-lome/Earthway EV-N-Spread 20.
For ornamental plants and vegetables, use two cups per 100 square feet. After that, use ½ cup of 16-16-16 fertilizer per 25 feet of row. Lay the fertilizer down in a band three inches from the plants and scratch it in the soil, then water the fertilizer in. As I mentioned, I recommend using 16-16-16 only for the initial fertilization and then switching to a lower nitrogen fertilizer.
Lily Miller 16-16-16 Lawn and Garden Food is my pick for the best overall fertilizer. I like it because it is widely available and can be used on a lot of plants. This product is spread as a dry fertilizer and then watered in after spreading. It is water soluble. The 40-pound bag covers 8,000 square feet. It contains nitrogen, phosphorus, potassium, and sulfur. The fertilizer is fast acting but needs to be repeated every month. This product was developed for farmers to use at planting and each month to grow lush, green vegetables and plants. It is now available to homeowners. I would use it in early spring to wake up my ornamental plants, trees, and shrubs. For trees and shrubs, apply again in six to eight weeks and then in the fall. This fertilizer doesn’t have a label for use on houseplants, so I would use the Maxsea instead on them.
To fertilize new lawns with Lily Miller 16-16-16 Lawn and Garden Food, water the area the day before. The next day, I would use two cups of 16-16-16 fertilizer per 200 square feet. Spread with a spreader and mix into the top two to three inches of soil. Water the soil after spreading the fertilizer. I would not use it for an established lawn for the reasons already mentioned above. The bag of fertilizer has a long list of spreaders and how to set them to properly spread the Fertilizer. I am sure most people will be able to locate their spreader and the proper setting for it on the list.
To fertilize ornamental plants and vegetables with Lily Miller 16-16-16 Lawn and Garden Food, use 1 ½ cups per 100 square feet of area at planting and work into the top two to three inches of soil. As mentioned above, I would not use this fertilizer for ornamentals and vegetables after planting, because it has too much nitrogen in it. Overfeeding vegetables and ornamental plants can lead to smaller and less flavorful fruit and fewer blooms, so don’t add extra fertilizer.
What Are the Ingredients in 16-16-16 Fertilizer?
All 16-16-16 fertilizer contains sixteen percent nitrogen, sixteen percent phosphorus, and sixteen percent potassium. Some triple 16 fertilizers contain other nutrients and proprietary ingredients designed to help the plants use the fertilizer. The rest of the fertilizer bag is inert ingredients designed to make the fertilizer easier to use.
In conclusion, 16-16-16 fertilizer contains 16% nitrogen, 16% phosphorus, and 16% potassium. I found water-soluble and granular formulations. I was unable to locate a liquid or an organic formulation. I picked Maxsea HGC722255 All Purpose 16-16-16 Hydroponic Nutrient Fertilizer as the best water-soluble 16-16-16 fertilizer, Hi-Yield (32351) Triple 16-16-16 Fertilizer as the best granular 16-16-16 fertilizer, and Lily Miller 16-16-16 Lawn and Garden Food as the best overall 16-16-16 fertilizer. Triple 16 is best used as the initial fertilizer in the spring for ornamental plants and vegetables, as well as for new lawns. It is used to fertilize trees and shrubs in the spring and fall. I would not use it after the initial fertilization with ornamental plants and vegetables because it has too much nitrogen. You will end up with lots of foliage and not many fruits or blooms.