We gardeners are an enthusiastic bunch that want to give our plants all they need to flourish. In addition to the right location, healthy soil, and water, which includes a balanced diet. It takes a lot of energy for a plant to produce flowers, fruit, seeds, all while developing healthy roots, and leaves for photosynthesis. Plants pull out nutrients as they grow, and fertilizing replenishes them.
Plants get their nutrients from the minerals and organic matter in the soil or from added fertilizers and compost. With the best of intentions, we routinely fertilize, whether the plant needs it or not. Rather than spend money on something that may not be necessary, here are some Earth-friendly ways you can get the most out of your fertilizer:
Know what your plant needs: Different types of plants have varying nutrient needs, and the soil’s ability to supply those nutrients can vary by location, season, and weather conditions.
Add only what’s needed: Most of the 18 chemical elements plants need for plant growth are already in the soil or the air and don’t need to be added regularly. Test your soil for the big three – nitrogen, phosphorus, and potassium (N-P-K), then add only the nutrients that the soil test results indicate are lacking.
Pay attention to soil pH (acidity / alkalinity): When pH is too low or too high, chemical reactions can alter the nutrient availability and biological activity in soils. Most garden and landscape plants grow best in a soil pH range of 6.0-7.0.
Use it at the right time of year: Fertilizing too early or late in the season can be a waste of material and money. If applied before seasonal rains end, nutrients may be leached out of the soil. Fertilizing in late summer and early fall can encourage tender late growth that is easily killed in winter.
Opt for natural fertilizers: Many organic materials (carbon-based and derived from living organisms) contain other essential plant nutrients in addition to N, P and K, provides carbon to feed soil microorganisms, increases soil organic matter, and improves overall soil health. Often sold as meals, these materials release nutrients slowly over a longer period, allowing plants to absorb them more efficiently.
Know what you’re using: It’s easy to be swayed by costly specialized products for different plant types – one for azaleas, roses, citrus, etc. Often these products are simply N, P and K in various concentrations. You can get the same nutrients in more affordable, generic products. Before buying, read the product label and be sure it contains what you need.
More is not better: Too much fertilizer, whether applied too often, too much in a single application, or added at the wrong time, can burn or desiccate roots. It can lead to weak, succulent growth, encourage insect pests and disease problems, and contribute to water pollution.
Take care with controlled released products: Pellet-like granules of multi-element fertilizer are coated with a substance that slowly breaks down allowing the release of a small, steady amount of nutrients over time. However, the types of coatings used vary and may include synthetic polymers which may persist in soils.
Avoid multipurpose products: These products contain a mixture of fertilizer, insecticide, and fungicide, or fertilizer and herbicide (weed and feed lawn products). Using combination types of fertilizer products when there is no specific insect pest, disease, or weeds present adds pesticides to the soil for no purpose. It can negatively impact soil organisms, bees, and other pollinators, and is much more expensive than single use products.
Not a cure all: Fertilizers won’t help plants injured by insect pests and diseases, location, or weather problems unless soil nutrients are deficient.
By Nanette Londeree, Master Rosarian