Why you should add oyster shell to your plant's soil
Crushed oyster shell is an underrated soil supplement that holds multiple benefits for soil and plant health. As organic gardening gains in popularity, this natural conditioner is starting to be favored over synthetic options.
What’s inside oystershells?
Clint Patterson https://unsplash.com/photos/SFe3ldnqVr0
Oysters shell is made from protein polysaccharides, 95 percent calcium carbonarte (chalk), and smaller amounts of the minerals magnesium, sodium, copper iron, nickel, strontium.
Horticultural oyster shelll can be made from the shells of any species in the mollusk family Ostreoidea. Whelks, a type of sea snail, have shells with a similar mineral profile.
What can oystershells do for plants?
Oyster shell’s calcium content is what makes it so valuable for the gardener. Calcium-enriched soils encourage better root development which ultimately feeds into a bigger, healthier-looking plant.
Calcium is an alkali substance that you can use to increase soil pH. While some acid-loving houseplants (like azaleas, African violet, and Begonia) appreciate low Ph soil and shouldn’t be given oyster shell, many others need an alkaline environment. Alkaline soils tend to contain more beneficial soil bacteria, which turn soil nutrients like nitrogen, phosphates, and potassium into forms that are more readily taken up by the plants.
If your plant isn’t doing so well, there is a chance that the soil environment isn’t to its liking. You can buy simple pH meters to measure the alkalinity or acidity of your soil easily. Low numbers (anything below 5) indicates acidity while higher numbers indicates alkalinity.
If you find that your soil is too acidic for your potted plants, this is very easy to fix. It’s simply a matter of mixing up a new potting medium that includes alkaline elements to rebalance the pH. Many gardeners add powdered Dolomitic lime (a type of mined mineral) to alkalinize soil, but this substance can cause skin and respiratory problems. Dolomitic lime also contains a lot more magnesium than oyster shell does, which can add unnecessary minerals to soil that is already well-fertilized.
Oyster shell is an equally effective alkaline agent but is less concentrated and works more slowly, reducing the risk of overloading your soil. Just mix in 1-2 tablespoons of oyster shell per gallon of soil. Calcium carbonate is one of the most stable minerals around meaning that it will stick around in your soil for a long time and you won't need to constantly top up.
Can I use oyster shell as fertilizer?
Oyster shell does contain minerals that plants need in very small amounts, like magnesium and copper. These are known as plant micronutrients. However, oyster shell cannot replace plant fertilizer because it lacks nitrogen, potassium, and phosphorus – the three minerals that your plants needs in the greatest amounts. You can use oyster shell in conjunction with plant fertilizers as it helps your plants take up nutrients like nitrate better.
Sustainable gardeners will appreciate the fact that oyster shells are highly renewable materials. In fact, most farmed crustaceans bring net positive benefits to the environment. Oyster shell is also cheap since it is sourced as a by-product from the seafood industry. You can buy in bulk and store for as long as you like. If you need smaller amounts, check your local pet shop. They will normally sell small bags of the stuff as a food supplement for caged birds.
Making oyster shell soil conditioner at home
For those who eat oysters and other crustaceans regularly at home, save any shucked shells to make your own shell-based soil conditioner.
You should bake the shells in the oven first to sterilize them and make them more brittle. Place the baked shells in a bag and smash with a rolling pin or similar until you have quite fine pieces. Throw the shell onto compost heap for a couple of months to break down. Although you can add fresh shells directly into your potting mix, the composted versions seem to encourage better growth.
Buy oyster shell online
Don't feel like saving shells, baking them and grinding them? Give your houseplants all the benefits of oyster shell with Southside Plant's very own finely-ground 5lb bag of horticultural oystershell.