Is the landscape hungry?
A sustainable landscape with a healthy soil food-web should be able to feed itself. Nevertheless, if at some point plants are showing nutrient deficiencies, it may be tempting to go to the hardware store and buy fertilizer for a quick fix.
However, if applied when unnecessary or in the wrong amounts, fertilizers will be unsustainable and detrimental, as they can lead to excessive new growth, increasing the need for maintenance and water. They can also lead to run-off and pollution.
The preferred sustainable treatment for nutrient deficient plants would be compost, and there are two ways that compost can be added to the landscape without disturbing the soil: top-dressing and compost tea.
Top dressing is simply applying compost in a 1/8 to 1/2 inch thick layer to the top of the soil in the deficient areas. Irrigating the area can then help to work the compost back into the soil.
Compost tea is made by soaking high-quality organic compost in water in a permeable bag such as cheesecloth until the resulting liquid is dark, like black tea. This can then be applied to leaves or to the root zones of plants.
A preventative, regular, yearly application of 1/2 to 3 inches of compost into the landscape will help to keep the soil alive, nutrient-rich and stave off health and disease issues before they happen.
Fertilizers will always have three numbers on their label, these are called the N-P-K numbers and they indicate the percent by weight of nitrogen, phosphorus and potassium. Simplified, nitrogen is used by the plant to build, phosphorus helps promote flower and fruit production while potassium strengthens the plant.
If fertilizer is determined to be needed, then sparingly use only organic, slow-release fertilizers. Here is a list of such fertilizers and their typical N-P-K:
- Bone meal, 4-12-0: Used to increase phosphorus
- Blood meal, 13-1-0: Used to increase nitrogen
- Compost, 2-1-1: Good all-around fertilizer
- Fish emulsion, 2-4-5: Strong all-around fertilizer
- Manure, 0.7-0.3-0.4: Used for slow release nitrogen
- Worm castings, 3-1-1.5: Well balanced, support soil food-web