Video:How to Choose Fertilizer for a Flower Garden

Transcript:How to Choose Fertilizer for a Flower Garden

Hi, my name Jim Willmott, plant health coordinator with the US Botanic Garden.  Today, we are going to talk about how to choose fertilizer for your flower garden.  

Testing Your Soil to Choose a Fertilizer

There are different fertilizers to choose from and your choice will depend on several factors including the plant's preferences and your soil content of nutrients. 

Testing your soil is important to determine the types of fertilizers that your plants need. Soil tests will tell you the soil acidity or basicity. We call that pH. It also will tell you the amount of phosphorus, potassium and micronutrients that are necessary. 

This can help us to determine not only the fertilizer but the type of lime and possibly the addition of other types of amendments such as gypsum which supplies calcium or epson salts which supply magnesium. 

What are the Different Types of Fertilizers?

There are different types of fertilizers: dry granular products and water soluble products and also controlled release. 

Granular fertilizers contain the essential elements. These are often applied before planting or what we call pre-plant. Now, they are sometimes applied later in the season as a top dressing. 

There are also water soluble fertilizers that are complete. These typically are applied during the season when the plants are growing. 

Granular fertilizers can be categorized in two ways, either synthetic or natural. Natural products are derived from natural sources such as cottonseed meal, alfalfa meal, or even composted manures. Natural products have the benefit of being derived from living organisms. And these also contain many other elements beside the essential elements that we discussed. This is very important for plant growth. 

There are also controlled or time release fertilizers available. And, the benefit of these is that they release over an extended period of time depending on temperatures and moisture. The disadvantage is that if you apply too much, tender plants can be burned. Also, they have the tendency to make soils more acidic and some plants may not prefer this. 

With this information, you will be able to choose the best fertilizer for your flower garden. 

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