Plain old water does the trick, but adding additives can boost plant growth and reduce mold and pests! Here are some things you can "water" your plants with!
And remember, you can flush your plants of accumulated salts and leftover fertilizer residue by watering them with distilled water, which can be found for free from your air conditioner or dehumidifier.
1. Rice Water 🍙
It is packed with complex starches, trace amounts of nitrogen, potassium, phosphorus, and beneficial vitamins. The starches feed the beneficial microbes and mycorrhizal fungi in the soil, which in turn help the plant absorb nutrients more efficiently. If you let the rice water sit out for a day or two to ferment slightly, it creates lactobacilli that act as a natural soil probiotic.
How to use: Pour it directly onto the soil at the base of the plant.
CAUTION: Ensure the water is completely unseasoned (no salt, no butter) and cooled to room temperature before applying.
2. Eggshell "Tea" 🥚
The Calcium Fix: Eggplants, tomatoes, and peppers are highly susceptible to "blossom end rot," a condition caused by a lack of calcium that turns the bottoms of the fruit black.
How to use: Rinse a few empty eggshells, crush them up, and pour boiling water over them. Let the mixture sit overnight to extract the calcium, strain out the shells, and use the calcium-water on your eggplants.
3. Banana Peel "Tea" 🍌
The Potassium Boost: Bananas are packed with potassium, which plants need to produce strong flowers and healthy fruit. Potted citrus orange trees and dwarf apple trees use up a massive amount of potassium during their fruiting cycles and respond incredibly well to this.
How to use: Drop a banana peel into a mason jar of water, put the lid on, and let it sit at room temperature for 24 to 48 hours. Remove the peel (you can toss it in the trash or compost) and pour the potassium-rich water directly onto the soil.
4. Epsom Salt Water 🧂
The Magnesium Boost: Epsom salt is magnesium sulfate. Magnesium is a critical building block for chlorophyll. Citrus trees and eggplants are notorious for magnesium deficiencies, which usually show up as leaves turning yellow while the veins stay green.
How to use: Dissolve 1 tablespoon of plain, unscented Epsom salt into a gallon of water and water the soil once a month during the growing season.
5. Vegetable or Pasta Water 🫗
The Vitamin Shot: How to use: When you boil or steam vegetables (like spinach, carrots, or broccoli), many of the micronutrients and vitamins leach into the water. Pasta water acts similarly to rice water, adding beneficial starches to the soil. Companion plants like mint, lavender, and basil thrive on these gentle nutrient boosts.
CAUTION: The absolute most important rule is that the water must be completely unsalted and cooled to room temperature. Salt will accumulate in containers and severely burn the roots.
6. Sparkling Mineral Water 🍾
The Oxygenator: Unflavored, unsweetened sparkling mineral water contains dissolved macronutrients like carbon, oxygen, sulfur, and phosphorus. The carbonation can also help aerate the soil slightly.
How to use: If you have half a can of plain club soda or mineral water that has gone flat, pour it right into the soil. (Just ensure it isn't a brand with high sodium content).
7. Unflavored Gelatin 🪼
The Nitrogen Kick: Plain, unflavored gelatin is an excellent source of slow-release nitrogen, which is exactly what leafy herbs need to produce lush, green foliage.
How to use: Dissolve one packet of unflavored gelatin in a cup of hot water, then stir it into a quart of cold water. Pour it directly onto the soil of nitrogen-hungry plants like mint or basil once a month.
8. Blackstrap Molasses ☕
The Microbe Feast: Unlike fruit juice, the complex carbohydrates and trace minerals (iron, calcium, magnesium) in unsulfured blackstrap molasses are fantastic for the soil. It doesn't feed the plant directly; instead, it feeds the beneficial microbes and mycorrhizal fungi in the soil, sending them into overdrive so they can process nutrients for the plant's roots.
How to use: Dissolve 1 tablespoon of blackstrap molasses into a gallon of lukewarm water and pour it onto the soil. Do this sparingly (once every month or two).
9. Black Coffee or Green Tea ☕
The Acidifier: Both coffee and tea are slightly acidic and contain small amounts of nitrogen. Citrus trees in particular love acidic soil and benefit from the occasional coffee splash.
A well-brewed compost tea introduces billions of beneficial microbes directly to your soil. By steeping rich compost in aerated water, you create a liquid solution that helps the plant's roots absorb ambient nutrients much more efficiently. It sends the soil ecology into overdrive, acting as a force multiplier for whatever other fertilizers you've applied.
How to use: Dilute leftover black coffee or tea with an equal amount of tap water and pour it into the soil once every few weeks.
CAUTION: It must be plain—no milk, no cream, no sugar, or you will invite mold and ants.
10. Vinegar Water 💦
RISKY: Use with Caution. Vinegar is a dilute form of acetic acid. Because it is an acid, it is sometimes used to acidify soil pH or kill weeds.
Citrus trees and figs, along with other kinds of plants, prefer slightly acidic soil (around a 5.5 to 6.5 pH). If your local tap water is very alkaline (hard water), it can raise the soil pH over time, locking up nutrients so the plant can't feed.
How to use: A highly diluted vinegar mixture (1-2 tablespoons of plain white vinegar per gallon of water) can occasionally be watered into the soil to gently lower the pH and neutralize hard water.
CAUTION: If mixed too strongly, vinegar will strip the protective waxy coating off plant leaves and chemically burn the roots. In fact, horticultural vinegar (which is stronger than household vinegar) is frequently used as a natural herbicide to completely kill unwanted plants. Never spray vinegar directly onto the foliage of your eggplants or fruit trees.
11. Baking Soda Water 💦
RISKY: Use with Caution. Baking soda (sodium bicarbonate) is commonly recommended online as a DIY fungicide to treat powdery mildew, a disease eggplants and squash (and more) are very prone to. However, it can be quite dangerous to the plant's roots.
It changes the pH on the surface of the leaf, creating an alkaline environment where mildew spores cannot survive.
How to use: Never pour it directly into the soil. If you must use it for mildew on plant leaves, use a very weak dilution (1 teaspoon per gallon of water, plus a drop of dish soap to help it stick), spray only the leaves, and try to avoid letting it drip heavily into the potting mix.
CAUTION: Baking soda contains sodium. When growing plants in containers, sodium doesn't flush out easily. It builds up in the soil and causes salt toxicity, which burns roots, scorches the edges of leaves, and eventually kills the plant. In coastal or canal environments where ambient salt levels might already be slightly elevated, adding sodium to the soil is a bad idea.
12. Milk 🥛
RISKY: Use with Caution. Milk is an old-school gardening trick, but it is very risky in warm, humid weather and container gardens.
Milk contains calcium and beneficial proteins. A highly diluted milk spray is sometimes sprayed on the leaves of plants to fight powdery mildew. The proteins in the milk interact with sunlight to create a mild antiseptic effect on the leaf surface.
How to use: If you have a few drops of milk left in a jug and want to give your plants a calcium boost, dilute it heavily (1 part milk to 10 parts water) before watering. However, eggshell tea is a much safer, smell-free way to get that same calcium to your plants.
CAUTION: If poured directly into potting soil, the fats and proteins in the milk will curdle and spoil in the heat. The soil will start to smell like rotting garbage, which will immediately attract flies and scavengers. It can also cause harmful fungal growth in the container.
13. Ice 🧊
RISKY: Use with Caution. Watering plants with ice cubes is a popular convenience trick, mostly promoted for orchids, but horticultural experts generally do not recommend it for most houseplants.
It limits the amount of water introduced at one time, which can stop soggy soil or root rot in pots without proper drainage.
CAUTION: It can cause root shock and uneven watering, as well as inadequate saturation.