Plant Food is Essential for Healthy Growth
By Susan Richards
Hopefully those frosty nights are in our rear-view mirror and plants will continue to grow well with the nice spring weather we have been having. Leaves on trees and shrubs have popped, early perennials are blooming, and lawns have greened up. It’s essential that you start to feed all those plants, so they continue to thrive.
I often get asked about the best time in spring to begin to fertilize. The simplest answer is always to start once you see active growth.
Spring bulbs should be fertilizer as soon as you see the leaves emerge from the ground. The food you provide now will help them store energy, so flowers appear year after year. Right now, I have daffodils and tulips blooming in my garden. I gave them an application of granular fertilizer a week ago. Once the blooms fade and the leaves turn yellow, I will give a gentle twist and tug on the foliage. If it’s ready, it will detach from the bulb below.
I also have spring perennials blooming in my gardens: primrose, brunnera, bleeding-heart and more. They give me such joy each year! They are long lasting perennials that have been in the garden for many years and, with adequate fertilizing, will bloom for many more to come.
If you haven’t fertilized your flowering bulbs and perennials, be sure to do that now.
Fertilizers are available in many different forms and formulations. They have been developed to feed specific plant types so read packages carefully to determine the type you need. There is fertilizer specific to cedars, lawns, roses, clematis, and tomatoes. There are also more general-purpose fertilizers available for flowering plants, evergreens, vegetable gardens and for transplanting.
Many fertilizers are made with organic ingredients and are certified for organic growing. That information with be on the package too.
I have mentioned this information in previous article, but it certainly is worth repeating. All fertilizers have 3 main nutrients listed on the package and they are always in the same order, for example 15-30-15. The first number indicated the percentage of nitrogen by volume. The second number is the amount of phosphorus in the mix. The potassium content is indicated by the last number.
From the above example, 15% of the nutrient in that fertilizer is nitrogen, 30% is phosphorus and 15% is potassium. That only adds to 60% though. The final 40% is other micro-nutrients and the carrier that holds the all the food.
Nitrogen is essential for healthy leaf growth. Phosphorus aids in root and flower formation. Potassium helps overall plant health and helps plants toughen up for winter.
Fertilizer developers blend their products to target optimum growth for specific plant types. As an example, 10-15-10 is one of the liquid plant fertilizers available to use as a transplanting fertilizer. It helps establish a strong root system. 20-20-20 is an all-purpose fertilizer that can be used for many plant types. It’s often recommended for houseplants. 15-30-15 is a formulation developed to encourage lots of blooms on flowering plants.
Over the years the phosphorus content in fertilizer has been steadily dropping. Research has shown this nutrient lasts the longest in the soil so less is now needed. There is also concern about phosphates leaching into water supplies, rivers and lakes. Manufacturers have taken that concern seriously. You might have noticed that many lawn fertilizers are now phosphate free.
All nutrients must be dissolved in water for the roots to absorb the food. Be sure to water well after broadcasting granular fertilizer throughout the garden. If there is a heavy rainfall right after you have applied water-soluble fertilizer, you may have to reapply it. As the rainwater moves through the soil, nutrients will be leached away.
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