A fertilizer is any organic or inorganic substance of natural or synthetic creation that is added to a soil that supplies one or more plant nutrients essential to the growth of plants. Although fertilizers can be made with manufactured chemicals that will give great results, the safest and healthiest options are made with organic or naturally occurring ingredients. Regardless of your preferences, we've provided an informative fertilizer buyer's guide below which provides all the basics you need to know before starting your search.
Best Lawn Fertilizer:
Lawn fertilizers are formulated to promote lush, thick, beautiful green grass. In essence, and in most cases, the only thing a lawn fertilizer is good for is your lawn. To that end, the most important nutrient in a lawn fertilizer is the nitrogen content. Nitrogen makes your grass green and lush, which is exactly what you want out of a lawn fertilizer.
Although an organic fertilizer for your lawn is preferable, any biodegradable fertilizer that breaks down in the soil will work. The fertilizers on this list were selected because of their trusted brand names and proven lawn care results. These selections also offer the best bang for the buck which essentially means they’re economical to use by offering a low price with a high lawn coverage rate. Finally, they offer ease of application because all these fertilizers can be applied with a measured fertilizer spreader so you'll get precise spreading rates as the fertilizer is distributed across your lawn.
Milorganite 62036-MW Organic Milorganite Fertilizer is one of the most trusted fertilizers for lawn and gardens everywhere. It won't burn your lawn and the heat treated microbe organic formula makes it safe for use around kids and pets. Read Full Review
Safer Brand 9333 Ringer Lawn Fertilizer gives you a balanced blend of plant-based nutrients that naturally eliminates weeds while being safe to use around children and animals. 25 pounds covers 5000 square feet so if you want just one fertilizer that gives you the most bang for the buck, this is the best fertilizer on this list. Read Full Review
Miracle-Gro Lawn Food is easy to use, inexpensive and so concentrated you may only need to feed your lawn once or twice per season. One 5 pound box will cover 4000 square feet. If you don't want the hassle of fertilizing your lawn, but you still want it to look great, this is the fertilizer for you. Read Full Review
Scotts Turf Builder Lawn Food is inexpensive, is kid and pet friendly and features a high nitrogen content for a lush green lawn. It is one of the least expensive fertilizers here, and 12 pounds covers 5000 square feet. Read Full Review
Espoma Organic Based Lawn Food 15-0-5 comes from a 90 year old company known and respected to produce quality plant food products. It features a 15 percent nitrogen content for a lush and green lawn. The organic formula is safe to use around kids and pets, and 3.3 pounds covers 1000 square feet. Read Full Review
Best Tomato Fertilizer:
Tomatoes are heavy feeders and need to be fertilized regularly for superior results. For the best tomatoes, the fruit needs a fertilizer low in nitrogen, but higher in phosphorus and potassium. These are called the NPK (nitrogen, phosphorus, potassium) numbers. If there’s too much nitrogen, you get wonderful foliage growth, but unfortunately your fruits won't flourish. Phosphorus strengthens tomatoes, better equipping able to handle temperature extremes and other weather anomalies while Potassium is for better fruit development.
What this means is a balanced, NPK numbered tomato fertilizer with lower nitrogen and higher phosphorus and potassium is essential for a lush, successful tomato crop. All of the tomato fertilizers on this list were chosen because of their basic ingredients which will help you grow a bountiful supply of tomatoes. As top ranked fertilizers they’re also the easiest and safest to use, delivering terrific results as well as being respected and trusted by gardeners everywhere.
Dynamite Natural and Organic Mater Magic Plant Food is the best bang for the buck tomato fertilizer on the list. 1 tablespoon covers 1 square foot. It is OMRI certified organic, and feeds for 3 months before another application is required. Read Full Review
Espoma Tomato Tone 3-4-6 has been made for over 90 years, so you know it’s good stuff. This organic formula needs to be fed to plants twice per month at 3 tablespoons per plant mixed into the soil. The 3-4-6 formula means heavy fruit production over all. Read Full Review
Dr. Earth 704P Organic 5 Tomato, Vegetable & Herb Fertilizer is made with essential microbes, fish meal, and seaweed. Although mainly intended for tomatoes, it can also be used as a whole garden fertilizer as well. Read Full Review
Schultz Tomato Food Fast Acting Water Soluble 17-18-28 feeds at 1/2 cup around the base of tomato plants every 6 weeks. Water soluble, it can also be made into a liquid fertilizer as well. Always wear gloves during application, and wash leaves after fertilizing to remove any granules that may burn the leaves. Read Full Review
Miracle-Gro 100440 LiquaFeed Tomato, Fruits and Vegetables Plant Food works best with the optional sprayer which mounts the bottle on top. 1 bottle covers 400 square feet and the best results are achieved when plants are fed every 7 to 10 days. The 9-4-9 NPK formula assures you of lush plant growth and good fruit yields. Read Full Review
Best Organic Fertilizer:
The best organic fertilizers for general gardening are a combination of fish ingredients such as fish emulsion or fish meal. Fish emulsion alone provides a solid Nitrogen, Phosphorus, and Potassium (NPK) nutrient factor which makes a terrific fertilizer base. The best fish emulsion fertilizers aren’t cooked but rendered in a cold making process that keeps the vitamins essential to plant growth fully intact. Can certain other organic products be substituted or added to enhance or replicate this formula? Of course, but starting out with a fish emulsion base assures you that your plants will have the essentials for superior growth and health.
The organic fertilizers on this list were selected because they contain the necessary ingredients that every organic fertilizer should have to make your plants lush and bountiful, they’re proven to work based on manufacturers testing, and provide a fertilizing component that will work equally well for both the novice as well as the experienced gardener.
Neptune's Harvest Organic Fish/Seaweed Fertilizer Blend 2:3:1 is OMRI certified organic, and uses a cold process to preserve all of the vitamins and minerals in its fish emulsion formula. The seaweed mix gives a balanced feeding ratio, and 1 ounce per gallon of water, every 3rd week, is all you'll need for the best in organic vegetables or flowering plants. Read Full Review
Milorganite 0636 Organic Nitrogen Fertilizer is best for lawns, although it can be used as a fertilizer for all plants, shrubs and trees. Used by the best golf courses, the high nitrogen content assures you of a lush green lawn. It spreads at a rate of 36 pounds per 2400 square feet. Read Full Review
Azomite - OMRI Organic Trace Mineral Soil Additive Fertilizer is best used as an additive to your regular organic compound. Add between 40 grams and 120 grams of this mineral powder during your regular fertilizing regimen. The low NPK formula of .5:.5:15 makes it best suited as an additive. Read Full Review
Espoma Plant-Tone Organic 5-3-3 Plant Food has been in business since 1929, a testament to the superiority of their product. It contains 15 essential nutrients, and can be used on virtually all types of plants. It is one of the easiest to use plant fertilizers on this list. Read Full Review
Jobe's 6528 Organic All Purpose Fertilizer Food Spikes are the most efficient way to feed your plants at the roots. Push them into the soil at the beginning of the growing season, and forget about it until next year. This is the easiest fertilizing option on this list. Read Full Review
Fertilizer Buyers Guide
Fertilizer has been used for virtually as long as humans have been growing food crops. In the “new world”, Native Americans taught the colonists how to use fish heads as fertilizer to supplement their corn and other food crops. The fish heads were dried out and then ground up to effectively create the first powdered fertilizer; in this form it could be used anywhere and stored easily. In fact, a derivative called fish meal remains one of the main ingredients found in many fertilizers to this day.
In this modern world, a wealth of manufactured and organic fertilizers are available to choose from. However, different types of plants need different types of nutrients for optimum growth and productivity. This guide only provides the most basic of information so for a more in-depth understanding of fertilizer, contact a certified horticulturist, a home and garden specialist, or an agriculture expert at your local university.
Virtually every fertilizer is classified by the three basic ingredients needed for healthy plant growth. These are nitrogen, potassium and phosphorus, or known as N-P-K numbers.
“N” is for nitrogen.
Nitrogen is one of the basic building blocks in every plant. It affects the health and growing cycle of a plant cells and is naturally derived from organic decomposition. The more nitrogen added to the soil, the taller and more vigorous a plant will grow. Since nitrogen allows a plant to produce more chlorophyll, plants with an abundance of nitrogen will also be a darker green than those that don’t grow in nitrogen rich soil.
“P” is for Phosphorus.
Phosphorus promotes root growth and blooming. This naturally occurring substance comes from both the weathering of rocks and minerals into the ground. The uptake of these minerals occurs from organisms which eat decaying plant matter and then excrete the phosphorus back into the soil.
“K” is for Potassium
Potassium is like a medicine plants need to remain healthy. This compound makes a plant more drought resistant, improves root development, and it makes a plants photosynthesis, (the process that uses sunlight to synthesize food from carbon dioxide and water) more efficient.
Although the N-P-K numbers are only used to show the nitrogen, phosphorus, and potassium content, there are generally other nutrients added. These “micro-nutrients” are comprised of such ingredients as iron, manganese, molybdenum, zinc, and copper, among others. Much like people who take a multi-vitamin to ensure they get all of their nutritional needs, adding in these micro-nutrients (plus trace elements like sulfur, calcium, and magnesium) gives plants their own full multi-vitamin nutritional needs.
Manufactured fertilizer is generally inexpensive and will promote stellar plant growth with an abundance of flowers and fruit. It’s usually high in nitrogen and phosphorous which contributes to rapid green plant growth while also promoting flowering and larger fruit yields.
Ammonia and nitric acid are combined to achieve high nitrogen levels in the form of ammonium nitrate. Phosphorus is manufactured by dissolving mineral laden rocks in sulfuric acid, while potassium is made by treating potassium hydroxide with hydrochloric acid. Micro-nutrients and trace elements can then be added to this mix for a more complete fertilizer, such as ground up animal bones for calcium and powdered molybdenum and zinc metals, among others.
Organic fertilizers are made from all natural ingredients with the largest source of organic fertilizers coming from manure, compost, blood meal, and seaweed. For example, manure and blood meal produce both nitrogen and phosphorus while seaweed, compost, and wood ash are great sources of potassium. While micro nutrients and trace elements can be added to these fertilizers, most of the essentials are already present since the plant and animal compounds already contain them naturally.
Synthetic vs. Organic
There’s an ongoing debate about which type of fertilizer is healthier to use for you and your plants. The most comprehensive study to date from the Newcastle University in London, England, has proven that organic foods are healthier and provide more base nutrients and anti-oxidants than commercially grown food.
In general, manufactured fertilizers can be engineered to last longer and require less fertilizing than their organic counterparts. Very high N-P-K numbers can be achieved with manufactured fertilizers, because you can concentrate the ingredients through artificial means. By adding a coating to the fertilizer granules, these types can be made to dissolve slowly over the course of weeks or months. You may only have to feed your plants 2 or 3 times throughout the year to maintain healthy and productive growth.
On the other hand, organic fertilizers break down quickly once spread. They have lower N-P-K numbers and because of this you'll need to fertilize more often, sometimes weekly if your plants are heavy feeders. They are more time consuming to use and require more work to use utilize correctly. However, if you're concerned about chemicals showing up in your edible plants, organic fertilizers are the way to go.
What's Best for You
Lawns, Trees, Shrubs, and Houseplants
These plants are all ornamental for which any good high nitrogen fertilizer will work. Remember, the nitrogen makes plants green and ornamental plants such as lawns and shrubs look the best when they have a vibrant, dark green hue. A high nitrogen content is the most valued fertilizer for these types of plants, but in southern climes or where the weather can be dry over long periods of time, a fertilizer which contains a higher potassium count will help promote deeper root growth.
Flowering Plants and Trees
The most valuable fertilizer for these plants are those with a higher phosphorus content. Certainly, both nitrogen and phosphorus are needed, but a flower garden or ornamental flowering trees will produce a greater amount of larger, longer-lasting flowers if the fertilizer has a higher phosphorus content.
Fertilizers with a lower nitrogen content with higher phosphorus and potassium contents are the best fertilizers for edible plant gardens. Plants bearing edible fruits and vegetables need to produce more flowers and buds, and this also goes for fruit trees as well. They also need to be hardy and disease free, so both the phosphorus and potassium ingredients should be more prominent for edible plant gardens. In doing so, you'll reap the rewards in the form of more fruit on healthier plants.