If you're looking to grow the perfect garden but your soil could use a bit of work, you can buy any number of fertilizers that promise to provide your soil with the nutrients it needs. But not all fertilizers are alike when it comes to environmental impact.
Many commercial fertilizers are made from ammonia, which is extracted from natural gas using a complex chemical process. This process also releases carbon dioxide—the heat-trapping gas primarily responsible for global warming—into the atmosphere. Nitrates in the resulting fertilizers can harm both humans and marine mammals by seeping into groundwater or drinking water supplies. And, in the ultimate irony, because these fertilizers are generally very acidic, they eventually have the opposite effect of the one intended, depleting the soil of nutrients and killing healthy bacteria and other essential organisms.
Fortunately, there are environmentally friendly alternatives to chemical fertilizers you can buy in a store or make yourself. Here are some tips that can give you both healthy plants and healthy soil:
At the Garden Shop
- Choose a plant-specific organic fertilizer designed for what you are growing. Different plants require different nutrients, even in the same garden.
- Use slow-release organic fertilizers that nourish as they decompose in the soil. Most contain fish meal, bone meal, or blood meal derived from food-processing waste. Others include fruit and vegetable waste, kelp and earthworm castings.
- Apply a liquid organic fertilizer when plants are in need of a quick boost. These consist mainly of seaweed and fish-processing wastes.
- Avoid fertilizers made from municipal sludge (also called biosolids). These are often labeled organic, but have been found to contain heavy metals and other toxic chemicals that can build up in your soil.
- Make your own nutrient-rich soil supplement by turning food wastes you would otherwise throw in the trash into compost. An inch or so of compost added to your garden each year is often all you need to maintain healthy soil.
- Dry some coffee grounds and scatter them around plants that need a nitrogen boost. Your local coffee shop may be willing to give you its old grounds—it never hurts to ask!
- Provide additional calcium for your soil by spreading dried, crushed eggshells.
- Make your own liquid fertilizer by mixing seaweed—an excellent source of potassium—and water in a container and letting it decompose for about two months. Since the resulting liquid will be concentrated, you'll need to dilute it before adding it to the soil.
Reprinted with permission from the Union of Concerned Scientists
Dog Owners Beware: Cocoa Bean Mulch Poses Threat To Pets
As people begin to tend to their gardens this spring, some will consider using cocoa bean mulch as a fertilizer. Made from spent cocoa beans used in chocolate production, the mulch is organic, deters slugs and snails, and gives off an appealing chocolate scent. However, it also attracts dogs, who can be poisoned by eating the mulch.
Cocoa beans contain the stimulants caffeine and theobromine, and dogs are highly sensitive to these chemicals. Low doses can cause mild gastrointestinal upset; higher doses can cause rapid heart rate, muscle tremors, seizures and even death.
The ASPCA Animal Poison Control Center recommends pet owners avoid using this mulch around unsupervised dogs, and dogs with indiscriminate eating habits.