By Kathleen Harvey, Owner, Plant Artistry, LLC
When I first met my honey and saw his houseplants, they were sickly things sitting in the corner and on windowsills, desperately trying to survive. I asked him, “What are you feeding those poor plants?” His response: “Food? Am I supposed to share my dinner with them?” His answer, though a bit comical, was not uncommon.
Understanding plant nutrition requirements doesn’t have to be complicated, but there are differences for house plants and landscaping plants, primarily because of the potting medium and small cramped space we ask our houseplants to grow in. There are also differences between organic and synthetic.
Do plants really care where they get their nutrients? Yes, because organic and synthetic fertilizers provide nutrients in different ways. Organic fertilizers are made from naturally occurring mineral deposits and organic material, such as bone or blood meal or composted manure and kitchen scraps. Synthetic fertilizers are made by chemically processing raw materials.
Chemical fertilizers differ from organic fertilizers in the rate at which the nutrients become available to the plant. Synthetic fertilizers are water-soluble and can be taken up by the plant almost immediately. In fact, applying too much synthetic fertilizer can chemically burn foliage and damage your plants. Synthetic fertilizers give plants a quick boost, but do little to improve soil texture, stimulate soil life, or improve your soil’s long-term fertility. They can also leach out into streams and ponds, especially chemicals applied to lawns. Synthetic fertilizers do have some advantages in early spring. Because they are very water-soluble, they are available to plants even when the soil is still cold and soil microbes are inactive.
Organic and natural fertilizers usually have a lower N-P-K (nitrogen, phosphorus and potassium) number. They are considered soil amendments (as opposed to fertilizers) that work slowly over time to improve your soil and to help your plants grow strong. In general, the nutrients in organic fertilizers are not water-soluble and are released to the plants slowly over a period of months or even years. For this reason, organic fertilizers are best applied in the fall so the nutrients will be available in the spring. These organic fertilizers stimulate beneficial soil microorganisms and improve the structure of the soil. Soil microbes play an important role in converting organic fertilizers into soluble nutrients that can be absorbed by your plants. Earthworm castings and properly prepared compost and compost tea are teeming with these beneficial organisms. Compost moderates soil pH and is one of the best ways to maintain the 6.5 ideal to absorb phosphorous. In most cases, organic fertilizers and compost will provide all the secondary and micro nutrients your plants need.
Healthy soil is the basis for healthy plants. For the long-term health of your garden, feeding your plants by building the soil with organic fertilizers and compost is best. You might not need much fertilizer in your garden. You may just need to liberate the nutrients already present in your soil with beneficial soil organisms, proper soil aeration, soil drainage, and re-mineralization. This will give you soil that is rich in organic matter and teeming with microbial life. Feed the soil that feeds the plants that feed us!
