Garden Recycling: Using Household Wastes to Build Soil and Repel Pests
One of the satisfactions of gardening is the ability to work sustainably and close loops. Instead of just buying inputs and discarding wastes, gardeners can reuse discarded materials, reducing both cost and waste.
Compost is the primary example of this recycling. Some household discards also have more specialized uses in the garden. And, some don’t even have to be composted to utilize their thrown away nutrients. Here are five household wastes to recycle in the garden and how to use them:
Eggshells can be used as a slug barrier or a soil amendment. Coarsely crushed eggshells sprinkled in a ring around plants can keep slugs away. The soft-bodied slugs don’t like to drag themselves across the sharp-edged eggshells.
Finely ground or decomposed eggshells add calcium to your soil. While calcium gets less attention than the Big 3 of garden fertilizers (nitrogen, phosphorus and potassium), it’s vital to the health of your plants, helping them with water uptake and cell development.
Calcium is apt to be deficient or unavailable in dry, acidic or high-potassium soils. Calcium-deficient tomatoes and peppers are susceptible to blossom end rot. Calcium-deficient potatoes are small and susceptible to brown rotten spots. And, calcium-deficient broccoli may not produce heads.
To give a quick calcium boost, grind eggshells finely by pounding them with a mortar and pestle or drying them well, putting them in a plastic bag and pulverizing them with a hammer or rolling pin. Hand-crushed eggshells added to the soil, or large pieces of eggshell added to the compost, will boost calcium in the long term when they break down.
It takes a lot of eggshell to make a difference. Some people suggest putting 1/2 cup of pulverized eggshells in the bottom of each planting hole before setting out tomatoes. See the article on blossom end rot below for more information.
Eggshells also have a mild liming effect, raising soil pH and reducing acidity. Once again, eggshells must be finely crushed if you want to see quick results.
2. Coffee Grounds
Coffee grounds are a good source of nitrogen. Some people collect grounds from coffee shops to use in their compost piles in place of manure. The pH of coffee grounds is usually near neutral. If you’re adding them to compost, mix them well with high-carbon materials like leaves or straw so they’ll break down well.
Composted coffee grounds improve soil structure and attract earthworms. Fresh coffee grounds, like fresh manure, can ‘burn’ plants on contact. All your garden plants need some nitrogen. Nitrogen-loving plants that will especially benefit from the addition of composted coffee grounds include lettuce, spinach and cole crops (broccoli, cauliflower, kale, Brussels sprouts etc.)
3. Wood Ashes
Wood ashes are used both to fertilize soil and to raise pH and reduce acidity. Ashes are a good source of calcium, potassium and phosphorus. They can be added to compost piles or mixed directly into soil. Do not use large quantities of wood ash as a fertilizer if your soil is already too alkaline. See the article below for more information.
4. Pine Needles
Pine needles can be used to lower soil pH, making it more acidic. They can be used as mulch around acid-loving crops like blueberries and strawberries, or added to compost in areas with overly alkaline soil. If you are adding pine needles to the compost, increasing their surface area (mowing over them) will greatly speed up the time needed for them to breakdown.
5. Lawn Clippings
Lawn clippings are nitrogen-rich and they decompose quickly. Add them to your compost pile or use them as mulch around nitrogen-loving plants. Don’t apply them in layers more than one inch thick or they may start to break down anaerobically and stink. Avoid using clippings from lawns treated with pesticides or herbicides.
Want to learn more about using recycled household wastes as soil amendments and pest control?
Useful article on recycled soil amendments: Improve Your Garden Soil this Fall. This article written specifically for Colorado, with its thin, calcium-rich, alkaline soil. Generally speaking the Eastern US is more apt to have acid soils, the West to have alkaline soils. To learn about soils in your area contact your local Cooperative Extension.
Article on calcium deficiency and blossom end rot from University of Wisconsin-Extension.
Using Wood Ash on Your Farm from University of Maine Cooperative Extension.