Written by Angela Quayle, horticulturist
We’ve all been watering our landscapes during the long hot summer, and while our plants need this supplemental water, it has leached some important nutrients from the root zones of our trees, shrubs, and gardens. The way we can replenish this “food” is by fertilizing, and now is the time to do it.
Fertilizer comes in three physical forms: liquid, water-soluble crystals, and granules.
Liquid fertilizer comes ready to use or in concentrated form. When applied to plants, it is taken up quickly, and results are seen within a day or so.
Water-soluble fertilizer is usually in a concentrated form and is added to water before application. It is also taken up by the plants quickly, and results are seen in a day or so. In addition to working quickly, liquid and water-soluble fertilizers are depleted from the soil quickly and must be used relatively often. A weekly application is usually appropriate.
Granular fertilizer is applied directly to the soil around a plant and dissolves over time with each application of water. This form certainly takes longer to see results, but it lasts longer and only needs to be applied every few weeks.
I usually, though not always, choose liquid or water-soluble fertilizers for flowers and vegetables and use granules for my trees, shrubs, and lawn. The reason is simply convenience. You can always use the same fertilizer, called all-purpose fertilizer, for everything in your landscape. Unless you have tons of free time on your hands, use a granular fertilizer, because who has time to fertilize an entire landscape with a liquid fertilizer every week?
When you decide to actually apply the fertilizer of your choice, water your plants first! This is a very important step. If the soil is dry when you apply any form of fertilizer, especially while temperatures are warm, you risk burning your plants. Simply watering first will avoid this problem. Once your plants are watered, apply the fertilizer you have chosen, always following label directions. When using fertilizer, more is not better. Too much fertilizer leads to burning your plants as well. If you have applied a granular fertilizer, use the hose to water it in immediately and again each day for a few days afterward. After that, your irrigation should do the job sufficiently. You don’t need to fertilize in the winter, and your last application of fertilizer should be in September. Any later and your plants’ new growth could be damaged by frost. You can begin fertilizing again in March.
Don’t starve your landscape! Plants need food too! Just water first, follow the label for application rates, and water especially well for a few days afterward. Your plants will thank you … well, not verbally, of course, but by looking lovely and flowering like crazy!
In addition to choosing the physical form of fertilizer, you also have the choice of using organic or conventional fertilizer. I prefer to use organic or organic-based fertilizers. You must make this choice for yourself and your landscape. There are pros and cons to using each, but that is another topic for another day. Until then, keep calm, and go fertilize something.