With Spring in the Northern Hemisphere, many of us are itching to get our hands dirty and plant some flowers or vegetables. If you do container gardening or keep houseplants, chances are you’ve used potting soil — sometimes called potting soil or growing medium. It’s better to dig up soil in your garden to fill your pots. Potting soil isn’t quite as innocent as it sounds, however. Most potting soils are actually soilless and contain at least one rather unsustainable component. Luckily, making your own potting soil at home is pretty easy.
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What’s in potting soil?
You will find that most potting soils are very light compared to in-ground soil. This helps retain water and makes it easier for tender roots to easily break through the growing medium. Many varieties also contain fertilizers to help the plants grow quickly. In addition, it is usually sterilized so that it does not contain insects or diseases or spread seeds unintentionally.
What’s in this stuff you ask? Not all potting soils are the same, but most share some common ingredients.
This neutral medium absorbs water and provides aeration and drainage. Unfortunately, sand mining is not well regulated and is often environmentally destructive, impacting low-income communities and destroying habitats.
Vermiculite is a degraded mineral that expands into light particles when heated, increasing the porosity, drainage and aeration of potting soil. It also adds beneficial calcium and magnesium to the soil and increases the soil’s ability to hold water. While the material is considered organic, any degradation has a negative impact on surrounding land, water, plants and animals.
Perlite is volcanic rock that is also mined, with associated environmental impacts. When heated, it expands and looks like small, white styrofoam balls. Perlite is lightweight and adds porosity, aeration and drainage to potting soil.
Sphagnum peat moss
Not to be confused with peat moss, peat moss is a natural fungicide and is very lightweight and retains water very well. At the same time, it allows excess water to drain away. It is made naturally in wetlands over centuries of plant decomposition. But, unexpectedly, peat doesn’t contain many nutrients for plants to absorb. Like coal, peat is “natural” and “renewable” – but not to the extent that we use it. And, like coal, peat extraction has adverse environmental effects.
Wetlands are important ecological landforms that serve as habitats, stop migration, and filter out water pollution. In peat harvesting, the wetlands must be drained before the peat is scraped off the ground. It is then dried, sieved and compacted. The wetland and its inhabitants are very negatively affected. Wetlands are federally protected in the United States; Much of the peat used in potting soil comes from Canada and sometimes Russia. In addition, harvesting peat releases carbon dioxide, which is a major contributor to climate change.
Make DYI potting soil
When it’s time to fill up your garden pots or houseplant containers, why not mix up some homemade potting soil and skip the peat (and wetland destruction)? There are many readily available ingredients to make a quality potting mix.
Compost is a great addition to your DIY potting soil, especially if it’s compost you’ve rotted in your garden from kitchen and yard waste. Compost is high in nutrients and not as heavy as soil-grown soil. You can use it to replace the fertilizers in commercial potting mixes.
Coconut fiber is a by-product of the coconut processing industry. This lightweight fiber is an ideal sustainable substitute for peat as it holds water and adds drainage to DIY potting soil. Coir is usually sold in compressed blocks that expand when wet.
Wood shavings or pine needles are natural substitutes for perlite or vermiculite. Both wood alternatives will eventually degrade, but at the same time add nutrients to your soil.
You can also purchase perlite, vermiculite, and sand from your garden center if you want to add them to your homemade potting soil.
mixing the earth
Mix equal parts compost and coco for your soil – 6 gallons of each is a good starting point. Then add 3 gallons of wood shavings (or perlite or vermiculite). Experiment with the mix to get the texture and amount you need for your gardening needs. You may want to mix in some sand to get the texture you want.
You may also consider adding ground limestone, bone meal, or other fertilizers if you find your soil needs a pH change or additional nutrients.
Better store-bought soil in bags
If you’re only planting two small houseplants, there’s no point in buying all of those ingredients just to make a few cups of potting soil. Or maybe you don’t have the capacity or time to make potting soil. No guilt here; It’s okay to buy potting soil, but avoid bags that contain sphagnum peat moss. Look for brands that contain compost, worm droppings, or even bat guano instead of peat.