READ THIS NEXT: If Your Plants Are Dying, This Simple Trick Will Revive Them. The next time you’re hard-boiling eggs for breakfast, stop before you get rid of the water. Instead, use it to water your plants. “Eggshells are a rich source of calcium, a mineral that helps keep the soil pH between 6 and 6.5, the optimal conditions for plants to extract essential nutrients,” says DIY Garden blogger Emma Loker. “When you boil eggs, the calcium within the eggshells leaks into the water, creating a calcium-rich solution you can use to water your plants.” The water is also high in amino acids, another nutrient that contributes to plant growth. Plants require calcium “to support the growth and maintenance of their cell walls,” says plant care expert James Mayo. Without it, “most indoor plants will struggle to stay upright and will develop that limp ‘dead’ look,” he says. Likewise, “the calcium [from] eggshell water provides structural support to plants, which strengthens their leaves and stems,” All About Gardening CEO Jason White explains. “Eggshell water acts as a fast-release fertilize [because] nutrients are distributed faster into the plant’s system, leading to rapid results,” says White. “The fact [that] the plant can absorb and uptake the calcium so quickly is also the reason why most people will notice a visible improvement in the appearance of their plant after just a few hours,” adds Mayo. The calcium and amino acids in the water can also improve sick plants. Master gardener Andrew Porwol notes that these nutrients “boost your plants’ immune system and help them recover from disease while at the same time reducing their stress.” READ THIS NEXT: If Your Plants Are Drooping, This Bathroom Product Will Revive Them. While hard-boiled egg water is the ultimate house plant hack, there is a small caveat. “The one critical thing to remember is to ensure the water has cooled back down to room temperature,” advises Mayo. “Applying hot water to plants will, unfortunately, lead to scorching and it may even kill the plant depending on how hot the water is.” After boiling, make sure the water completely cools down or even refrigerate it briefly to guarantee healthy houseplants. For more plant care advice delivered straight to your inbox, sign up for our daily newsletter. Another hard-boiled egg trick is to use the shells themselves. Master gardener Yvonne Savio explained to the LA Times that clean, dry eggshells can be crushed up and added directly to the soil so their nutrients will be absorbed by the roots over time. This isn’t a quick fix, though, so it’s better for long-term maintenance.ae0fcc31ae342fd3a1346ebb1f342fcb Adding finely ground egg shells directly to the plant is another popular technique. Reddit user Enigmatic_Starfish notes that this can act as an insecticide when sprinkled on top of the soil. They say this works “in a similar way to diatomaceous earth,” a common powder-like pesticide made of ground diatoms, the remains of fossilized algae. According to DiatomaceousEarth.com, the product has “tiny sharp edges that can cut through [insects’] protective layer and dry them out.” The structure of ground egg shells works similarly. Other types of liquid that would usually get dumped down the sink can work wonders on plants, too. Plant care website Gardening Know How explains that using diluted black coffee can help certain “acid-loving plants” because it “contains measurable amounts of magnesium and potassium, which are building blocks for plant growth.” And much the way eggshells’ nutrients seep into the cooking water, so do those from vegetables, making this yet another sustainable watering option.