West Coast Gardener – What Does it Take to Make Plants Grow?

by Kaitlyn Fuller, Peninsula Landscape Supplies – 

We live on this beautiful island in a climate where we get to see plants grow all year long, but what does it actually take to help these plants grow? To answer that question, we have to understand what the average plant requires for growth. The formula is actually quite easy and can be simplified down to five basic needs: sunlight, air, water, optimal temperature, and nutrients.

The first three of these needs are involved in the process of photosynthesis. Energy from the sun is absorbed through a chemical compound called chlorophyll, whose green pigment is responsible for the colour of leaves. This energy is used to convert carbon dioxide from the air into a sugar called glucose, and water into oxygen which is then released from the plant. The plant then uses glucose to make other molecules such as cellulose and starch, which are the building blocks of all plants. The oxygen in the air we breathe is mostly produced through this process.

Plants require an optimal temperature for photosynthesis, but this optimal temperature differs based on the type of plant. For example, strawberries grow best between 15°C and 25°C while geraniums are able to tolerate temperatures up to 35°C. What happens if the temperature is outside of this optimal temperature? At low temperatures, the rate of photosynthesis decreases dramatically, slowing the overall growth of the plant. At high temperatures, the proteins that are used for photosynthesis are damaged, and as a result the plant cannot continue with photosynthesis or growth at all.

The final basic need, nutrients, is the most finicky of all the needs. There are 16 essential nutrients that plants require, which can be further grouped into three main categories, primary (macro) nutrients, secondary nutrients, and trace (micro) nutrients.

Primary nutrients are required by plants in the largest amounts and include things such as nitrogen, phosphorous and potassium. Store-bought fertilizers often contain these macronutrients and are identified by three numbers that represent the ratio of Nitrogen to Phosphorous to Potassium (N-P-K). Nitrogen is generally responsible for encouraging leaf growth, and so a fertilizer with a higher ratio of Nitrogen is ideal for trees, shrubs and hedges. Phosphorous is largely responsible for root growth as well as flower and fruit production, so higher phosphorous in a fertilizer is ideal for fruit or berry development, as well as for transplanting bulbs. Potassium helps plants grow faster and stronger, aiding in more efficient production of flowers or fruit. This means that a fertilizer high in potassium will be ideal for vegetable or rose gardens.

Secondary nutrients are only needed in moderate amounts and include Calcium, Magnesium, and Sulfur. These generally help plants with nutrient uptake, as well as creating optimal pH for plant growth. Finally, micronutrients such as Chlorine, Copper, and Iron are only needed in trace amounts, and are almost always present in the soil that your plants grow in.

Now that you have the basic formula for how plants grow, go out and enjoy the science of your garden this spring!

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