It’s Wise to Fertilize


A Short Guide to Plant Nutrition


Plants, like people, need food to thrive. Without an available food source plants starve; leaves turn yellow, flowering and fruiting decreases, stems become weak and stunted and the plant slowly declines.


Understanding the N-P-K’s and What They Do

The three main nutrients (macronutrients) are Nitrogen(N), Phosphorous(P), and Potassium(K)
Nitrogen – promotes rich, lush growth and a healthy, dark green colour
Phosphorous – promotes strong, healthy root systems, flower production, seed development, early maturity and a normal healthy dark green colour.
Potassium – promotes strong stems and roots, disease resistance, winter hardiness and helps maintain a proper water balance within the plant.

The other macronutrients are Calcium, Magnesium and Sulphur which also perform a function in promoting healthy plant growth and are often included in a fertilizers formula.

Many fertilizers also contain micronutrients (iron, manganese, boron, zinc, copper, etc…) Those are also important for plant growth and development but are needed in very small quantities.

Take Note: Nitrogen is the most commonly deficient nutrient. It is not a mineral and is not naturally present in the soil as are other nutrients. Nitrogen needs to be added to soil in the form of decomposing organic matter or as fertilizer.


Choose Your Fertilizer

There are many types of fertilizer available:

Granular Fertilizers: dry fertilizer products that are spread on lawns or sprinkled then raked or dug into flower beds and vegetable gardens. They dissolve when they come into contact with water and begin their fertilizing action quickly. Depending on the product they can last for months.

Liquid Fertilizer: fertilizers that are dissolved or diluted in water. Particularly useful for container plantings and hanging baskets. Since the nutrients are carried in water they are available to plant roots immediately. They need to be used frequently and on a regular basis.

Specialty Fertilizers: those formulated for specific plants. They can be either granular or liquid products, e.g. Rose Food, Rhododendron and Azalea Food, Lawn Food.

Slow-release Fertilizers: bead-like granules that release small amounts of nutrients with each watering that are particularly useful for container plantings and hanging baskets. Can last 3-4 months and sometimes up to 6 months. Makes fertilizing less of a chore!

Organic Fertilizers: fertilizers containing nutrients that are derived from the remains, part of the remains, or a by-product of a once living organism (e.g. blood meal, bone meal, fish fertilizer, alfalfa meal). Organics release their nutrients slowly and are most effective when soil is moist and warm enough for soil organisms (which begin the break-down process allowing nutrients to be released) to be active.


Non-Organic or Organic?


Non-Organic Fertilizers

Pros

  • Pack more of a nutrient punch
  • Can be utilized by plants roots quickly
  • Cost less

Cons

  • Burn plants more easily if applied incorrectly
  • May harm beneficial soil organisms if applied incorrectly
  • May leach into nearby water sources if applied incorrectly


Organic Fertilizers

Pros

  • Improve overall soil conditions and feed micro-organisms
  • Less likely to pollute water sources
  • Less likely to burn plants

Cons

  • Slower acting
  • Inclined to cost more
  • Have lower nutrient values (N-P-K)

Take Note: Plants don’t differentiate between non-organic and organic fertilizers. As long as the nutrients are available in the soil and soil conditions are favourable, plants’ roots will take them in and plants will thrive.


Fertilizing Tips:

Follow the directions! Using too high a dose can burn delicate roots.

For container plantings make sure soil is moist before fertilizing. Applying a liquid fertilizer to dry soil may cause damage to plant roots.

Use a broadcast or drop fertilizer spreader when applying lawn food to guarantee even distribution.

Liquid fertilizers can be sprayed on as foliar feeds. The nutrients are absorbed through the leaves of the plants.

Perennials and shrubs are best fed with granular fertilizers and only need to be fertilized twice a year. Once in early spring (March-April) and again in early fall (no later than mid-October).

Now that you know the facts of fertilizing you should be able to choose the appropriate product for your plants particular needs. If you need further information Maple Leaf Garden Centre staff will be happy to help.