Tracy DiSabato-Aust (Garden Designer and Author) gives expert video advice on: What is 'fertilizer'?; What is the difference between fertilizer and soil amendment?; What are the primary nutrients that plants need to grow? and more...
What is 'fertilizer'?
Fertilizers are compounds that are added to, either the soil or the foliage of plants, to improve growth. We can have organic or inorganic fertilizers. Other types of fertilizers include granular, foliar spray, or soil drench. Soil drench is where we water the plant in with a water soluble fertilizer.
What is the difference between fertilizer and soil amendment?
Fertilizers are nutrient providing, so some soil amendments will actually provide nutrients, and they are fertilizers in a sense. Other soil amendments, for example sphagnum peat moss, sand, or gravel do not add any nutrients, so those are not fertilizers.
What are the primary nutrients that plants need to grow?
The primary nutrients that plants need to grow are nitrogen, phosphorous and potassium, usually listed as N, P and K. And there are three numbers that you will see listed on the fertilizer bags.
What is 'synthetic fertilizer'?
Usually chemically-manufactured materials. Some of the synthetic fertilizers would be Rapid Grow, Miracle Grow, and the Scholtz fertilizer.
What is an 'organic fertilizer'?
It's derived usually from plant or animal products. Organic is really the type of fertilizers that I select to use in my gardens. The nice thing with the organic fertilizers is that we have nitrogen, phosphorus and potassium provided, but also a lot of micro-nutrients that might not be available in synthetic fertilizers. They're safe to use. They're usually a slow release, so they're safe to use on the plants and they're safe for us as gardeners and for our animals and children in the gardens.
What is 'quick release' vs 'slow release' fertilizer?
Quick release is readily available to a plant and is often water soluble. With slow release, the nutrients are released over a period of time, which is sometimes dependent on temperature and the amount of moisture that's provided to the plant.
What are 'weed and feed' fertilizers?
Weed and feed fertilizers will control usually broadleaf weeds as well as fertilize. I do not advocate weed and feed fertilizers, neither in the garden nor on lawns, unless they are of an organic product.
How much fertilizer does my garden need?
I don't like to give blanket recommendations on that. It's usually best to test the soil, but a good general rule of thumb is 2 pounds of superphosphate and 2 pounds of a 5-10-5 per hundred square feet.
How often should I fertilize my garden?
How often you fertilize often depends on the type of plant grown and the nutrients that are available. I like to advocate the use of a nutrient-providing soil amendment, and when that is in the soil, you have a living soil and nutrients are being provided throughout. Very seldom do you need to add additional fertilizer, except perhaps with some of the heavier-feeding plants. An example would be delphiniums.