4 Types of Fertilizer and How to Choose One

Fertilizers come in four forms: compost, mulch, commercial synthetic products and organic products. They are applied using different methods. All fertilizers provide nutrients to feed the plants in your landscape, but each offers benefits that more accurately and efficiently target specific projects like a vegetable garden or lawn.

If you’re looking for ways to improve your lawn or garden, you may want to consider fertilizer. But which one? We’ve got the answer.

Fertilizers are a great way to add beauty and value to your property, but they do require a bit of commitment and physical labor. Luckily, there are plenty of products out there that will help you make all the right choices in terms of what type of fertilizer is right for your yard.

Synthetic Fertilizer

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Best for: Rapid results, lawns

Synthetic fertilizers are manufactured chemicals in liquid or granular form and also available as a slow-release product. Full strength fertilizers are ready to use, or you can purchase concentrates to mix at home. They quickly provide nutrients to your lawn, flower beds, and vegetable gardens.

In some cases, synthetic fertilizer is cheaper than natural alternatives like composting or manure. However, it can be more difficult to find out if these products are safe for your plants and the environment.

Synthetic fertilizers are fairly easy to apply and can be added to soil before or after planting. Liquid forms are often diluted with water or added when soil is wet after watering or rainfall, while granular fertilizers work best when watered in or worked into the soil.

Other fertilizers, primarily for trees and houseplants, are spikes that are pushed into the ground (trees) or pot (houseplants.) These are a slow-release type designed to break down over time for a longer, continuous feeding.

Synthetic fertilizer is a great way to get your plants off to the right start, but you’ll want to make sure that you’re using it consistently to ensure results.


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Best for: Improving soil, vegetable gardens

Compost is a mixture of organic materials like grass clippings, dry leaves, and other decaying plant material. It is most often applied by tilling or digging it in to existing soil. You can make your own compost pile or purchase it at a nursery or garden center by the scoop or bag.

It is easiest to add before planting but can also be added at the time of planting or afterward as a side dressing. Compost has to break down in the soil before the nutrients are available to plants; this makes composting a slow-acting fertilizer with results that last through several seasons.

Compost is a way to improve your soil and attract beneficial organisms and microorganisms. It’s best used as an annual addition to vegetable gardens, flower beds and shrubs but not practical as an addition to existing lawns. Compost can also be used to fertilize your plants and trees, but it’s eco-friendly and inexpensive.

Tip: Planting a cover crop in your vegetable garden can help you build more fertility into the soil. Different types of clovers, buckwheat and alfalfa are planted in the fall or early spring and then tilled in before planting. The decaying vegetation breaks down and adds nitrogen to the existing soil. It can also crowd out unwanted weedy growth.

Commercial Organic Fertilizer

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Best for: Small applications, discouraging rodents

Although there are many commercial organic fertilizers, some of the most common ones include bloodmeal, bonemeal, bat guano, fish emulsion, and kelp meal. Some improve soil’s acidity or alkalinity and add a specific element to your garden soil.

These fertilizers can be found at garden stores and plant nurseries. But because they’re not free or cheap to purchase, you’ll have to weigh how much you want to spend on them with how much work they require or how large a garden area they can be applied to.

Bloodmeal, fish emulsion and bonemeal all make good fertilizers for Cole crops (such as tomatoes, peppers, beans and squash) and other vegetables. Bloodmeal adds nitrogen to the soil and has the added benefit of deterring rabbits and other small rodents that are repelled by the odor. Fish emulsion makes an excellent foliar spray for feeding seedlings, while bonemeal is high in phosphorous which promotes root growth to support healthier plants.

Tip: Animal manure is another type of organic fertilizer that can be purchased at a garden center or farm supply store. It comes in bags, and you should read the label before buying it to make sure it’s been prepared under controlled high heat conditions to kill pathogens. Commercially sold manure is generally safer than manure fresh from the barnyard.


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Best for: Protection, appearance

Mulch is a very useful way to improve your garden soil. It can be created from different materials like tree bark, straw, decaying leaves and other natural materials. Common types of mulch are cedar, pine and hardwood shavings, chips or nuggets.

Straw is sold by the bale in most places and pine straw is also sold by weight when you can find it. Grass clippings and leaves are usually gathered from your own yard; these types of mulch slowly break down over time to add nutrients and improve the texture of the soil.

Mulch serves several purposes in the garden, including holding in moisture and providing a cool surface. It suppresses weeds and often serves as protection for plants during winter. Finally, mulch adds a lovely finished look to your flower beds, as well as other plantings.

There are many materials that gardeners call “mulch” that don’t contain any nutrients for their plants and, in fact, may not be ideal for their gardens at all. Some mulches are made of rubber, stone, plastic, or other inorganic materials.

Some decorative colored tree bark mulches contain dyes that may leach into the soil water. Stone takes a very long time to break down; however, it can hold minerals which can leach through watering.

Tip: Sometimes, communities offer free mulch to property owners. The mulch usually contains wood chips, clippings and other natural materials collected from yards or public works projects. Keep in mind, though, that free mulch doesn’t come with an ingredient label so it’s a good idea to be selective about how and where you use it.

Choosing a Fertilizer

Choosing the best fertilizer for your yard and garden projects can be simple. You don’t always have to limit yourself to one type of fertilizer. You can add nitrogen rich synthetic fertilizer in the beginning of the vegetable garden season and then side dress your crops with compost, manure or commercial organics mid-season. Although bark mulches don’t work well in the vegetable garden they are effective in combination with synthetic fertilizers for flowerbeds and trees.

A synthetic fertilizer is a product that can be applied to an existing planting, such as a lawn, established flowerbed or trees and shrubs. It boosts growth and doesn’t require disturbing the soil. When you need slow-release granular fertilizer for vegetables before transplanting or sowing seeds, choose one high in nitrogen. Orchid plants and houseplants also benefit from an early application of a slow-release granular fertilizer high in nitrogen before setting them out in their permanent homes.

Adding compost to the soil before planting will help the garden grow. It’s organic and works best for long-term soil improvement. Vegetables are planted in the same place every year, which depletes nitrogen. To keep the nutrients replenished, add them with an annual addition of organic compost.

If you’re planning on adding compost to flower beds, it’s best to work it into existing soil as soon as possible after you’ve planted. You can also add it at planting time or as a side dressing to both food crops and flowers during the growing season.

Natural mulches add to the beauty of flowerbeds, vegetable gardens and other outdoor spaces by slowing down the decomposition of organic matter. They’re applied in spring or fall, and if they’re not added every year, they’ll gradually break down as a slow-release fertilizer for your garden projects. A few natural mulches—straw, leaves or other plant materials—can work in a vegetable garden, but because they break down more slowly than compost does, won’t supply the annual nitrogen requirement for most crops.

Reading NPK Ratios

Plants need three essential nutrients: nitrogen, phosphorous and potassium. Synthetic fertilizer labels carry an NPK ratio that tells you what percentage of each mineral makes up the product. The NPK ratio is 15-10-10, meaning that a product contains 15 percent nitrogen, 10 percent phosphorous and 10 percent potassium. Secondary minerals, resins and fillers may also be listed on the label to help you determine if your fertilizer has everything you need.