Posted By: Michelle Kuehler /
As we mentioned last week, fall is the time to fertilize. When choosing a fertilizer from your local lawn and garden retailer, like our organic fish fertilizer Nature's Balance 231, keep the following in mind from our Chief Science Officer Dr. Wesley Chun.
Most fertilizers list three numbers on the label, which describe the nitrogen, phosphate, and potash (NPK) formula. For instance, the NPK rating for our Grower's Secret 521 is 521.
Nitrogen is important for a plant’s early growth and helps make them green and leafy (Top). Tomatoes love nitrogen and will deplete the soil of it, so it’s important to add more. Phosphorus strengthens roots, wards off disease and helps with fruit and flowering (Down). Potassium helps regulate how plants synthesize proteins and starches and help them deal with extreme weather conditions (All-Around).
The NPK numbers should be interpreted on your lawn and garden with a "Top-Down, All-Around" approach. This approach describes where the major effect of NPK occurs in the plant. Understanding this will help you choose the right fertilizer for your lawn and plants.
Starting in September, grasses start to actively grow with the cooler season. Supplying the grass with fertilizer that supports the “Top” is the initial goal. In October or November use fertilizers that support the “Down” and “All-Around” growth.
Plants on the other hand are starting to fade with the cooler weather, so fertilizers that support “Down” growth is recommended. In all cases, the main goal is to promote healthy root growth during this time of year.
In any case, be sure to not over-do it with the fertilizer. It's always better to use too little fertilizer rather than too much, since nitrogen and phosphorous not absorbed by your lawn can cause nutirent pollution in the waterways when washed into storm drains and watersheds.