Fertilize Plants to Boost Spring Growth


By Susan Richards

April showers bring May flowers, or so the old saying goes. In the plant world, moisture and nutrients go hand in hand with warmer soil temperature to kick start spring growth. We have certainly had enough rain in April to do the trick!

I see active growth in my perennial gardens. Crocuses are blooming and daffodils will follow soon. I sprinkled fertilizer throughout my gardens last week to give plants a healthy start.

For a spring application of fertilizer for lawns and gardens, I do prefer an organic, granular type. It releases slowly as spring rains arrive, giving little boosts of nutrients frequently. Time your application to an expected rainfall so the fertilizer gets released to the roots.

Liquid and water soluble fertilizers are best used in summer when plants are growing rapidly and able to absorb food quickly. Any excess fertilizer left in the soil in spring gets quickly leached away with rain.

Every fertilizer package has three numbers identifying the major nutrients provided. The first number is the percentage of nitrogen in the fertilizer. Nitrogen is the nutrient that promotes strong leaf growth. Spring lawn fertilizer is always highest in nitrogen.

The second number on the label is the percentage of phosphorous in the mix. This nutrient promotes healthy root growth. Fertilizer recommended for transplanting is always highest in phosphorous. Bonemeal is an example of this type. Its numbers are usually 0-14-2. (If you live in an area where wildlife, such as raccoons, squirrels or skunks tend to dig up you new plants, use a liquid transplanting fertilizer instead. It has the advantage of not attracting animals.)

You may have noticed that good quality lawn fertilizer now has little or no phosphorous in it. That is because this particular nutrient is very slow to break down. Major testing throughout the province has shown that there is an adequate supply in the soil for healthy grass growth.

The last number on the fertilizer package gives you an indication of the percentage of potassium present in the mix. This nutrient promotes overall health, flower bud formation and plant hardiness. It is often the highest number on a package of fall fertilizer. It helps plants toughen up for winter.

A balanced fertilizer feeds all parts of the plant. An example of this type of food is 20-20-20. I use this water soluble fertilizer throughout the growing season to keep my annuals healthy right into the fall. I alternate it with 20-8-20, a formulation for flowering plants, to encourage constant blooms.

If you would like to use fertilizer less frequently, try the slow release pellets. I have some on hand to put in all my container gardens. Then even if I don’t have time to use any other type of fertilizer, every time I water, the plants get a little shot of food!

There are also fertilizers formulated for specific plant groups. Many hours of research has gone into preparing the best blend for evergreens, trees and shrubs, hedges, clematis, acid loving plants, tomatoes or roses. Just follow the directions on the container, being sure not to apply more than recommended. Too much of fertilize can burn the stems and roots of plants!

Don’t forget to feed your tulips, daffodils and other spring bulbs. This is a group of plants that gardeners often forget to feed. In order for them to bloom year after year, they need to store nutrients in the underground bulb. As soon as you see their noses poking out of the soil you can work a bit of granular fertilizer around the plants. Anything formulated for flowering plants will work. If you didn’t think to feed them earlier, do it right now.

If you like to use fertilizer spikes for your shade trees, evergreens or fruit trees, wait until you see buds starting to break open and then pound them into the ground. Use the correct number of spikes as determined by the size of your trees, as indicated on the package. They are place at the drip line, or outer limit of the foliage where fine feeding roots are located.