Fertilizer is defined as a substance that the makes soil more fertile.
In other words fertilizer provides plants with nutrients that are needed to thrive. What the definition doesn’t mention is that too much fertilizer will kill or damage plants.
There are many different forms of fertilizer on the market making it hard to choose which one to use. All packages should contain application instructions informing the consumer how and how much fertilizer should be applied and how to do it.
Soil-conditioning fertilizers such as compost and well-rotted manure are placed on top of the soil or worked into the soil where they improve the soil structure and slowly release a low amount of nutrients over a long period of time.
This is one of the best fertilizers but it has the potential to carry weed seeds.
It is also heavy and takes time to spread. Soil can be top-dressed with compost or manure at any time of the year but it is usually done in the spring or fall when the plants are dormant or small.
Foliar fertilizer is sprayed on plant’s foliage when the plants are actively growing.
Plants absorb the nutrients through their leaves and quickly send it to other parts of the plants. Foliar fertilizer is quick acting and the change in plants can be very noticeable.
As the plants can not store great quantities of nutrients it is necessary to make a number of fertilizer applications in a season.
Other liquid fertilizers are applied to the soil as opposed to the foliage. The plant’s roots will absorb the nutrients and distribute it within the plant. Liquid fertilizers are very soluble and can be leached out of the soil by a heavy rain or excess watering. Fertilizer that is sold in a liquid form is often bulky to purchase and store.
Fertilizer is also available in powder that is then mixed with water to form a liquid fertilizer.
While it is easier to move and store, it might be harder to keep in solution. Make sure to accurately measure the powder and liquid when mixing the fertilizer.
If the fertilizer is too strong it will burn or kill the plants.
Granular fertilizer is as the name suggests, tiny pieces of fertilizer that are held together by a filler material. The filler material allows for easy distribution of the material. Without the filler it would be impossible to spread the fertilizer thin enough not to kill plants. Lawn fertilizer is the most common example of granular fertilizer.
Granular fertilizer can be fast or slow release. Quick release fertilizer will release most if not all it’s nutrients with the first rain or heavy watering. Slow release granules will break down over time releasing a smaller amount of nutrients with each wetting.
Fertilizer is also available in spikes or solid tablets which are placed in the soil near the plant’s roots. Nutrients are released each time the spike or soil becomes moist. It is important to place the fertilizer in the appropriate spot to ensure that the correct plants receive the nutrients.
Nutrients are important to plant growth but be careful to ensure that the plant is receiving what it needs as it can be killed with kindness.
Linda Tomlinson is a horticulturist and educator that lives near Rocky Mountain House. She can be reached at firstname.lastname@example.org