All-Purpose Plant Fertilizers

All Purpose Plant Fertilizers Buying Guide

In addition to sunlight and water, all your plants, both inside and out, need nourishment that cannot always be found in soil. Flowers, vegetables and houseplants require a regular diet of minerals and other nutrients to grow, produce foliage, flower and bear fruit. Sometimes, an all-purpose fertilizer is the only solution you will need for your typical gardening needs. It is helpful, however, to recognize the differences in your plants so you can decide which fertilizer is the best choice. There are many varieties of all-purpose fertilizers to choose from with various methods of application.



As you consider your options, keep the following questions in mind: 

  • Will an all-purpose fertilizer work for all your plants?
  • When should you begin fertilizing rose bushes for best results?
  • Do you need a fertilizer that is low maintenance?
  • Are the houseplants you are feeding actively growing?
  • How and when should fertilizer spikes be used?


Plant Characteristics, Fertilizer Types and Application

Most flowers, especially those grown in containers, benefit from all-purpose plant food. Some flowers and flowering shrubs such as roses, azaleas and rhododendrons, however, may require an additional fertilizer or more frequent application. Similarly, most vegetables grow well with all-purpose fertilizers, but there are some varieties that benefit from the addition of extra minerals, such as nitrogen. For houseplants, the formula of nutrients is somewhat standard, though some plants benefit from different fertilizer types depending upon whether they need frequent or infrequent feeding. Familiarize yourself with some of the differences between your plants before deciding if an all-purpose fertilizer will always do the trick.

Flowers: There are several varieties of flowers that thrive with regular feeding. For example, spring bulbs can benefit both at planting time and after the plants have emerged from the ground. Roses need more fertilizer than other shrubs and benefit from frequent feeding about three to four weeks after planting. Older roses and climbers have large root systems so they do not need feeding as often.

Other flowers that benefit from fertilizer include azaleas, camellias and rhododendrons. Compared to your lawn or vegetable garden, these flowering shrubs may require less fertilization, but light applications of plant food enhance their appearance and help ensure beautiful blooms.

        • Use bone meal at planting time to help bulbs grow strong roots and blooms
        • For established roses, start feeding in springtime when new growth is about 6-inches
        • Roses that continue to bloom all summer need regular feeding
        • For azaleas and acid-loving shrubs, use fertilizer with iron, sulphur and magnesium
        • Flowers need lots of phosphorus so make sure this nutrient is present
Vegetables Vegetables: Fertilizers help plants grow quickly so you can enjoy vegetables as long as possible before the first frost. Many gardeners worry about fertilizing plants that are meant to be eaten, but fertilizing vegetables is a common practice. Consult the fertilizer package if you have any concerns. Bear in mind that different vegetables require varying frequencies of application. For this information, consult the seed packet, plant growing information or the fertilizer package to determine how often to feed your vegetable plants.
        • Add a few inches of compost or manure to prepare soil before planting
        • Vegetables grown in pots require more plant food than those in the garden
        • Leafy green vegetables prefer fertilizers high in nitrogen
        • Broccoli and sweet corn also require more nitrogen than other plants
        • Peas and beans derive nitrogen from the air and do not require much from fertilizer
Houseplants Houseplants: Similar to garden plants, houseplants usually enjoy a time of rapid growth during the warm spring and summer months when sunlight and long days are the norm. During this time, you may notice your inside plants are "hungrier" and benefit more from plant food. During winter, the same plants will enter a resting phase, at which time you can skip the fertilizer. Choosing a fertilizer for your houseplants depends upon the types of plants you have. Foliage houseplants prefer formulas higher in nitrogen, while flowering houseplants benefit from fertilizers with higher phosphate. All-purpose fertilizers work well for most plant types, but check the label to make sure.
        • Water-soluble formulas work best if you feed plants weekly or monthly
        • For houseplants that go months between feeding, consider slow-release formulas
        • Always check the fertilizer label -- more food is not better and can actually harm plants
        • Brown roots and leaf tips, wilting, and white residue on pots may indicate over fertilization
        • Under-fertilized plants often have weak stems, pales leaves and fewer flowers
Application: Consult the following chart to learn about how to apply different types of fertilizer and make sure that your plants are getting the proper nutrients and minerals they need to survive.

Fertilizer Type


Fertilizer Spikes • Drive fertilizer spikes into the soil next to a plant at the drip line, about 2 inches
  under the surface of the soil
• Place at least 2 feet away from the trunk of a tree or shrub
• Apply once or twice per season
• Keep plant watered
Granular • Shake granules onto topsoil or mix into soil with hands, a spade or a small
  shovel before planting
• Water thoroughly after spreading
Liquid • Use liquid fertilizers for vegetables growing in containers as they require more
  plant food than vegetables grown in the garden
• Apply liquid fertilizers as part of your regular plant watering -- either with a
  watering can or as part of an irrigation system for outside flowers and plants
• Apply either to leaves or to soil, depending upon the plant (check growing
Organic • Use a lawn or handheld spreader to evenly distribute organic fertilizer over
  topsoil in a large area to prepare soil for planting
• Water thoroughly after spreading
• Mix organic fertilizer into soil before planting then follow up six weeks later
  with another variety
Slow Release • Spread on top of the soil in and around plants and work into the soil for slow,
  steady feeding for up to three months or longer
• Can also distribute directly into a planting hole for new plants or transplanting
• May use with drip irrigation systems
• Water thoroughly after spreading
Water Soluble • Measure water-soluble granules into a watering can or sprayer container then
  mix with water
• You can also apply water-soluble fertilizers as part of your regular plant watering
   -- either with a watering can or as part of an irrigation system for outside flowers
   and plants
• If using water-soluble fertilizers with irrigation systems, make sure fertilizer is
  completely dissolved beforehand or the fertilizer can clog the system
• Apply either to leaves or to soil, depending upon the plant (check growing


Organic: Organic fertilizers are made from natural ingredients, such as manure, bone meal or blood meal and are broken down by soil microorganisms for the gradual release of nitrogen and other elements.

Water Soluble
: Water-soluble fertilizers are powders or granules that are mixed with water, are easy to apply and make nutrients immediately available to plants. Plants derive nutrients from this type of fertilizer through their foliage and root systems.

: Available as either a soluble powder or a liquid, these fertilizers are first dissolved or mixed in water and are then sprinkled or sprayed onto plant leaves or applied using a watering can. Liquid fertilizer is quickly and easily absorbed into a plant's root system for an immediate boost. Because they leach into soil, liquid plant food needs frequent application, compared to other types. Liquid fertilizers can be used to help prevent transplant shock. Liquid fertilizers are also the easiest variety to incorporate into an irrigation system.

Slow Release
: Slow-release fertilizers are sold as dry granules or pellets and work by releasing small quantities of nutrients each time a plant is watered. This type can be shaken onto the soil or pressed into the soil in pellet form. Slow-release fertilizers can last in soil from a few months to several years, which is one reason why these types are usually more expensive and are much easier to maintain. Slow-release formulas become activated by water so they work best underground where it stays damp.

Fertilizer Spikes
: Fertilizer spikes are hardened, slow- or controlled-release dry fertilizers in the shape of a stake or spike, which is inserted into the soil of container plants, shrubs or trees.