What to Put in Water for Houseplants? An Overview

Do you want to give your houseplants the best care possible and have therefore been wondering what you can put in their water to make them healthier, shinier, and grow faster? Not all ingredients added to water for houseplants are as effective or work for all types of plants. It’s important to know what additions to water are actually beneficial for your plants.

It is beneficial to add standard fertilizer, coffee, cooking water, or banana peels to water for houseplants. On a regular basis, these ingredients have proven to promote the health, growth, and appearance of plants by depositing nutrients in the soil such as nitrogen, potassium, calcium, magnesium, and phosphor.

In this post, I have put together an overview including a list of all possible ingredients to put in water for your houseplants and also what downsides there are to some of these. After reading this article, you’ll know exactly what you can regularly put in water for the needs of your houseplants – and if you want to switch things up a bit you can come back to check out the list again anytime! Enjoy reading!

Why Add Anything at All to Water for Your Houseplants?

The bare essentials a plant needs are water, light, and soil. Though soils can be very different and the containing nutrient levels change with time.

Especially for potted plants, the nutrients in the soil are used up at some point as the earth cannot regenerate itself as it would in nature. That’s why with potted plants, it is important to help the soil on a regular basis to ensure your plants get all the nutrients they need in the long run.

Such additions to water are generally called fertilizers and help make the plant grow better and healthier or keep away pests.

An Overview: Additional Ingredients for Plant Water and What Benefits or Downsides They Have

You will find many different recommendations all over the internet of what ingredients you can use to fertilize your plants. Be aware that not all of them are as beneficial as is claimed.

That’s why I have collected a list of all the possible ingredients I found on the internet, why they are used, and also when they should not be used. I hope this will be helpful for you:

CoffeeContains nitrogen (against weeds and bacteria) as well as phosphor, magnesium, and potassium (promotes growth)Too much caffeine inhibits growth and makes the soil acidicUse cooled-down pasta water
Pasta WaterUse cooled-down potato waterContains starch which is full of vitamins and mineralsIf pasta water is salted, do not use
PotatoUse cooled-down green or black teaContains starch which is full of vitamins and mineralsIf potato water is salted, do not use
Tea– Only for acid plants such as roses or hydrangeas.
– Complicated to use as the pH level of soil need be determined before each use.
Contains potassium, phosphor, magnesium, and calcium for growth– Better used on acidic plants
– Do not use on a regular basis as it makes the soil more acidic
VinegarAdd one tbsp. of vinegar to a gallon of waterContains acidity good for acid plantsDilute one tbsp. of sugar to 1/3 of a gallon (or appr. 1 liter) of water
BananaSoak banana peels in water for several weeksContains high potassium levels for growth– Need to eat a lot of ripe bananas at once
EggshellsGrind eggshells and let soak in vinegar overnight. Dilute solution in waterContains calcium for growth– Only for acid plants such as roses or hydrangeas.
– Complicated to use as the pH level of soil needs to be determined before each use.
SugarBoost dying plants’ metabolism with extra sugarsDilute one tbsp. of sugar to 1/3 of a gallon (or appr. 1 liter) of water– Is only meant to boost dying plants, do not use it on healthy plants!
– Is harmful on a regular basis as it damages the roots of plants
Soda/CokeContains sugar to boost dying plants’ metabolism with extra sugarsDilute one tbsp. of coconut powder in 5 gallons of water– Is only meant to boost dying plants, do not use it on healthy plants!
– Is harmful on a regular basis as it damages the roots of plants
AshesDilute in water or distribute in soilContains potassium and calcium carbonate for growth– Works better in soil than in water
– Difficult to obtain if you don’t have a fireplace
Coconut– Very high dilution is needed, can make it difficult to mix it rightContains electrolytes and beneficial bacteria for overall health– Very high dilution is needed, which can make it difficult to mix it right
HairSoak in water overnight or stick them into the soilContains magnesium for growth– Needs to soak for 1-2 days
– If you own no pets and have to use your own hair, it will be difficult to obtain a good amount regularly
Matches– Difficult to obtain if not near the ocean
– A long process of cleaning and soaking until ready to use
Contains magnesium for growth– Is a chemical, not a natural ingredient
SeaweedSoak in water for 4 weeksActs as a fungicide in soilContains nitrogen (against weeds and bacteria) as well as phosphor, magnesium, and potassium (promotes growth)
Baking sodaDilute 4 tbsp. of baking soda in one gallon of water– Excessive use causes root rot and funghi
– Do not use on a regular basis
– Effects are ambivalent, and often don’t work
MilkDilute milk in water in equal partsContains calcium and proteins– Excessive use causes root rot and funghi
– Do not use on regular basis

The Most Common Additions to Regularly Put in Water for Houseplants Explained

If you read through the list above, you realized that the list of ingredients that can be added to plant water is long, and not all of them are as effective or meant for regular use on all plants such as vinegar or sugar.

For the best results in your plant care, I have summed up for you the most common ingredients that work for all types of plants and how to use them:

Add Industrial Fertilizer: For Overall Increase in Growth and Health

Probably the most common option is store-bought, industrial fertilizers for plants. Standard or organic fertilizers can be bought in any store that sells plants.

Make sure you buy fertilizer that suits your plant species and growth method: There are different fertilizers for plants kept in soil or water, for succulents, herbs, orchids, and so on. Read the specifications on the bottles.

Important Note: Industrial fertilizers are very effective. Always stick to the appropriate amount of fertilizer as mentioned in the product description. Too much of it will harm your plants.

How to use such fertilizers: In summer, add fertilizer to the water every other week. In wintertime, stop fertilizing for some months as your plants are resting during that time.

Recommendation: For the benefit of the environment, I strongly recommend buying an organic fertilizer to treat your plants as naturally as possible.

Add Banana Water: Lots of Potassium for Better Growth

Banana water has been shown to have good results with all types of plants. It takes some time though to properly make it. Here’s why:

For making banana water, also referred to as banana peel tea, you need to soak several banana peels in water for a couple of weeks until the peels turn black and the water turns dark.

You can speed the process up with some tricks though:

  • Use very ripe banana peels
  • Cut the banana peels into pieces and shred them further in a blender
  • Boil the soaked banana peel after some days to break down the fibers faster

It takes a while to make this fertilizer, but I find it a great natural option that comes at almost no cost if you eat a lot of bananas anyways. You also reduce your own waste by using banana peels instead of throwing them.

The Perfect Extra: With all the bananas you peeled, bake yourself delicious banana bread!

Add Pasta or Potato Water: Boost Your Plants With Starchy Cooking Water Full of Vitamins and Minerals

I find this to be a very helpful addition to normal watering. Cooking water is readily available in most households and therefore doesn’t cost anything extra. It is also one of the most beneficial for the overall health of plants. The starch released from pasta or potatoes into the cooking water will help plants to take up nutrients from the soil, like a general metabolism aid working from the soil.

What is important to know is that the cooking water should best be unsalted. I recommend using potato water, as the pasta water is usually saltier which harms your plants over time. Unsalted potato water is the go-to in my opinion.

If stored with a lid in the fridge, it can also last up to one week. For longer storage, just freeze it until you need it next time.

I find it also easy to use as there is no right or wrong amount if the water is unsalted: Just add some cooking water to your watering can once every other week. Be sure to stir the cooking water up before watering with it as this mixes the nutrients better.

Tip: Also, cooking water from boiled eggs works well to give your plants extra calcium.

Add Coffee: Good Means to Keep Away Pests and Bacteria

Coffee with its high amounts of nitrogen is a good repellant against pests and bacteria that could harm your houseplants. In addition, it contains phosphor, magnesium, and potassium which promote plant growth.

As coffee is also readily available in most households, it comes with no extra costs and has proven to be a very effective fertilizer for plants.

Though I also want to remind you here of its negative effects: It can make the soil much more acidic and too much caffeine will inhibit plant growth. I strongly recommend using coffee only once a month to make sure it doesn’t harm your plants.

Though some claim pure coffee can be used, I recommend diluting the coffee with water in equal parts to avoid its negative effects.

Tip: If you have a leftover brew from your coffee machine, you can distribute a thin layer of it on the surface of the pots and exchange it every month or so. This helps especially against fungus gnats – the tiny little black flies you get in the soil sometimes.

General Tips to Keep in Mind When Adding Ingredients to Plant Water

  • Choose organic over chemical: Whenever possible choose natural alternatives that are good for the environment such as organic industrial fertilizers.
  • Use in summer, leave out in winter: Do not use additional ingredients throughout the whole year. Use them every second week in summertime and do not use them in winter as your plants are resting. Getting too much growth stimulus in winter but not enough light will cause stress and make your plants more prone to pests.
  • Alternate between one industrial fertilizer and one other natural ingredient: For best results, opt for one organic industrial fertilizer and one additional natural ingredient and alternate between these every other week.
  • Too much of any good will do harm: This phrase certainly applies to water ingredients, too! Try not to overdo it with the amounts of ingredients added to the water. Stick to product descriptions and indications of use.

Conclusion: Spice Your Plants’ Diet Up by Adding Beneficial Ingredients to the Water Regularly

Here’s a short sum-up of the whole post to make sure you remember the most important tips. The best ingredients for plant water for a regular watering habit are:

  • Organic, store-bought fertilizer
  • Banana peel water
  • Unsalted cooking water such as pasta or potato water
  • Diluted coffee

For the use of each, keep in mind:

  • Use regularly in the summertime, do not use in wintertime
  • Too much of any good will do harm: Stick to the indications of use for each of the ingredients and do not overdo it

All of the above-mentioned natural ingredients can be combined with an industrial fertilizer. Just make sure to alternate instead of giving both at the same time.

If you haven’t tried out any fertilizing ingredients yet, test them out for yourself and see which works best for your houseplants.

What Is the Best Water for Houseplants?

Not only matters what you put in your water for houseplants. An even more important basic question is what kind of water you use. Is salty water, rainwater, chloride-rich water from the tap, or distilled water best for houseplants?

Find out in my post covering all the different types of water you can use, what their benefits and downsides are and get to know great tips on how you prepare the best water you can.

What Other Ways Are There to Make My Houseplants Grow Better?

Looking for an alternative way to make your houseplants grow better and be happier?

There are plenty of studies that show how plants react to music and sound in their environment. If you treat them with the right sounds at the right time, it can prove to be very beneficial for your houseplants’ well-being.

Want to know more about plants and music? My post about the effects of music on plants, how plants actually hear, and how and what kind of music to use will be an interesting read for you. Enjoy reading!

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