I’m asked a lot about what makes a particular fertilizer “organic.” Essentially, its raw ingredients do.
Instead of using chemicals synthesized in a factory, organic fertilizers rely on natural plant, animal and mineral sources for their nutrients. Some of these fertilizers use by-products of the food industry — fish emulsion (although some types use whole fish and not by-products), bonemeal, feathermeal, bloodmeal, corn-gluten meal, and the like, while others use mined mineral nutrients like New Jersey greensand, rock phosphate, sulfate of potash and lime.
Still more sources include plant materials like alfalfa meal, cottonseed meal, kelp and pelletized compost. Some of my favorite brands of organic fertilizers are based on cricket manure (from bait farms) and worm castings (from worm composting operations) — nutrient dense and sustainable products. A quality organic fertilizer will state the source of nutrients right on the label, along with the macro-nutrient percentages (N-P-K).
An added benefit to using organic fertilizers is that many of them contain essential amino acids and trace nutrients that aren’t usually noted on the label and are rarely found in chemical fertilizers. Still another advantage in using organic fertilizers is the fact that because of the form of the nutrients, they are released through the action of soil microbes for plant use slowly over a long period of time; serving as a slow-release fertilizer over the course of the entire season.
A recent study out of the University of Massachusetts noted that chemical fertilizers release their nitrogen (of which only 40 percent to 60 percent is useable) within three to six weeks, while fish-based liquid fertilizer releases its nitrogen (of which 90 percent is useable) over the course of 15 weeks. Although the organic products might seem more expensive at first, you actually get more nutrients over a longer period of time, making them more than worth the extra dimes.
Here are some of my favorite organic fertilizers:
â¢ MegaGreen — A product made in Mississippi from the fresh remains of farmed catfish. It’s awesome for lawns. Its sister product, MegaBloom, is terrific for veggies and flowers, too. www.multibloom.com
• PlanTea — This fertilizer comes in a palm-sized tea bag. It’s brewed like tea, then applied to plants. PlanTea contains a hearty amount of phosphorus to stimulate root growth and blooms, along with other nutrients and amino acids. www.plantea.com
• SeaCrop Liquid Kelp — A kelp-based liquid fertilizer from North American Kelp Products. It comes in a liquid concentrate that is added to a hose-end sprayer for easy application to the entire veggie garden. www.noamkelp.com
• GardenTone — one of many organic fertilizers from the Espoma Company. The ingredients are listed on the label and include things like dehydrated manure, crab meal and cocoa meal. www.espoma.com
• ReVita Compost Plus — This comes from Ohio Earth Food and is made from poultry manure, kelp and humate. It’s good stuff. The N-P-K analysis is 3-3-3, all of it available in slow-release form. This is the most locally produced organic fertilizer I know of. www.ohioearthfood.com
• McGeary Organics — The main ingredient is dehydrated compost, but it also contains natural minerals, bone and blood meal. Higher in phosphorus for root and blossom growth. www.mcgearyorganics.com
It’s important to note that there are hundreds of other organic fertilizers on the market today, many of which are available at local nurseries. They all have different formulations and compositions, so be sure to choose according to what your garden needs. It’s also important to pay attention to the label and examine the ingredients: That’s the only way to be assured the product is truly organic. If the label has the OMRI (Organic Materials Review Institute) seal of approval, it’s guaranteed to be appropriate for your organic garden.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.
Send your gardening or landscaping questions to [email protected] or The Good Earth, 503 Martindale St., 3rd Floor, D.L. Clark Building, Pittsburgh, PA 15212.