How does your garden grow? If your answer is, "Not so good," it might be time for fertilizer. Simply put, to be healthy, plants require nitrogen, phosphorus and potassium -- sometimes known as the "Big 3." Nitrogen makes sure plants are healthy and nutritious; phosphorus supports photosynthesis and helps plants to grow and develop normally; and potassium protects the plants by strengthening the root system and preventing wilt. Brad Leahy, owner and vice president of Blades of Green, a Maryland lawn care and pest control company, says that fertilizers help improve plant health by replenishing these primary nutrients plants need to flourish. However, before you start adding fertilizer, consider what will work best for your soils and plants, and whether you should choose commercial or organic fertilizers.
"Generally speaking, organic fertilizers are processed minimally," says gardening expert and writer Jane Clarke. "They are made from plants, animal waste and minerals and are sold as a soil conditioner. Inorganic fertilizers are more processed -- usually made from petroleum products and rocks. Also, in the long term, inorganic fertilizers will damage the soil and the organic ones will improve its condition."
Homesteader Anna Miller prefers using organic compost made from food scraps to feed her soil. "The best thing to use is what is already available for free," she says. "Don't buy special fertilizer from the stores unless you have to. Use grass clippings, leaves and food scraps. If you do get pre-made fertilizer just read the instructions. I am not worried that fertilizer is bad for my health, but just believe the less chemicals the better."
Simple ingredients like coffee grounds and eggshells are especially effective in the garden. Coffee grounds are mildly acidic and provide a small amount of nitrogen. They also create a looser, well-hydrated soil, but they should be balanced with greens, such as grass clippings or leaves. Meanwhile, eggshells are packed with a variety of minerals, especially calcium. Crush them, or break them up, and spread them in your garden as a slow-release fertilizer.
"Adding compost to gardens is a good idea, in addition to fertilizer," says another expert gardener, Douglas Derick, who runs a landscaping service in New York. "Adding compost is similar to fertilizer but not the same. Compost mostly adds humic substances, which can house valuable bacteria and fungi as well."
"Fertilizer packs more of a macronutrient 'punch,'" Clarke says. "Although fertilizer adds nutrients to the soil, it is not a balanced addition of nutrients. When the soil is suddenly inundated with nutrients, the plants do get some of the nutrients, but meanwhile the microorganisms use up all the other available micro and macronutrients. This depletes a huge range of nutrients in the soil each time fertilizer is used." While powerful, it is essential to buy fertilizer with the correct nutrient proportions for your soil and apply it carefully to prevent fertilizer burn.
Sometimes a hybrid solution is best for your garden. Derick says most compost mixes don't quite offer enough bioavailable nutrients. That's why he likes to use fish- and kelp-based fertilizers along with compost. "Always use organic when you can," he says.
Clarke agrees: "Basically, I think it's better to use organic fertilizers as they are biodegradable, renewable and eco-friendly. Also, you can make them yourself. However, you have to keep in mind you won't see the result immediately and you'll have to be patient."
No matter what fertilizer you choose, don't go overboard. "Overfertilizing also harms the plants," Clarke says. "Constantly spiking your plants with fertilizer is about as healthy as feeding people sugar."
When it comes to plant health, you'll likely find the most success by tending to your soil as Mother Nature does: in moderation with all-natural ingredients. There's no one-size-fits-all solution, however, so see what's missing, and then formulate a fertilizer plan for optimal garden health.