Cannabis Science

Is Bong Water Good For Plants?

man inspecting plants

It’s natural to want to reuse things instead of throwing them out. After all, it’s better for the planet. You probably have a reusable tote bag for grocery shopping, opt for reusable containers, and have a water bottle you refill instead of constantly buying bottled water. You probably hate pouring your bong water down the sink. Especially since you may have heard that you can water plants with dirty dishwater. So what about dirty bong water?  Can you water plants with bong water? Is bong water good for plants? Here’s what we know.  

Photo: Unsplash

Can You Water Plants with Bong Water?

It depends on if you were smoking or vaping.

Winston Peki, a cannabis expert and owner of Herbonaut told Stoners Rotation that bong water used for vaping is a safer bet than bong water used for smoking. 

“Bong water that’s used in smoking contains significantly more toxins and tar than bong water used for vaping. Vaping reduces 80-90% of toxin release compared to smoking,” according to Peki. 

If you added tobacco to your cannabis, your plants could be in danger.

Peki told us, “When you combine tobacco and cannabis, you produce significantly more toxic by-products compared to cannabis alone.”

So can you water your plants with your bong water daily if you only used it to vape pure cannabis?

Not so fast. Peki told us, “Bong water from a bong that’s only been used for vaping pure cannabis, is alright every now and then (not every day).”

However, there is an exception. If you find your soil to be too acidic for your plants, then you can use bong water daily to restore the pH to normal. But why? Bong water brings up the pH. 

Peki says, “Bong water brings up the pH value of the soil because the decomposing plant matter inside the water has a high pH value.”

So, if unless your plants are growing in acidic soil, you’ll likely need an alternative source of water for your plants. 

How to Check the Acidity of Soil

Having acidic soil can be detrimental to plants. Acidic soil, according to Noble Research Institute can:

  • Increase soil solution toxic elements such as aluminum
  • Limit the availability of some of the important nutrients plants need
  • Poor crop performance

If you’re growing cannabis plants, it’s worth mentioning that the soil should be slightly acidic. Fluence says, Cannabis “tolerates a wide pH range (5.0-7.0) without symptoms…..but pH levels outside of the optimal range of 5.8 – 6.2 will limit growth.”

Cannabis plants aren’t the only ones that won’t thrive in acidic plants so keep these tips in mind for your other plants.

So, how do you know your plant is acidic? 

Almanac says you can:

  • Requests professional testing through your local county extension office
  • Buy a home test kit at a gardening center
  • Add distilled water and baking soda to a soil sample and look for fizzing

How to Correct Acidic Soil

One way you can correct acidic soil, as mentioned before is, by watering your acidic soil with bong water daily until the optimal pH is obtained. Noble Research Institute also suggests agricultural limestone. 

Noble Research Institute says, “As lime dissolves in the soil, calcium (Ca) moves to the surface of soil particles, replacing the acidity.” 

Then, “The acidity reacts with the carbonate (CO3) to form carbon dioxide (CO2) and water (H2O). The result is a soil that is less acidic (has a higher pH)”.

The optimal pH range will vary for various plants so make sure to find out which range you’re working towards. 

In addition to that, agricultural limestone isn’t an easy fix. Noble Research Institute says it can take up to a year to see measurable changes in the pH. 

Best Water for Plants 

If your plants aren’t growing in acidic soil, you need to water them with something other than bong water. 

So what’s the best water for plants? According to The Water Way, tap water isn’t a good option. 

The Water Way says, “tap water can be extremely dangerous to your plants’ health and how much or how quickly they grow.”

They suggest bottled spring water and rainwater. 

House Plant Hobbyist echoes the sentiment about tap water harming plants. However, they said it’s okay to give it some plants because not all of them are sensitive to tap water. House Plant Hobbyist reassures, “You can water plenty of plants with tap, but it may be worth checking out your local annual water quality report before giving it to your more sensitive plants.”

Distilled water and purified water are an option. However, House Plant Hobbyist says that even though contaminants are usually removed, important minerals and nutrients are also stripped. 

So according to House Plant Hobbyist the best water for plants is:

  1. Rain water (or melted snow)
  2. Spring water
  3. Water from reverse osmosis (with a balanced fertilizer)
  4. Water from a fish tank


Is bong water good for plants? It depends. Watering plants every now and then with bong water used for vaping is fine. In addition to that, adding bong water used for vaping to acidic soil can help to bring up the pH. However, bong water used for smoking can actually harm the plant. The best water, in general for plants is rain water. In most cases, you can just toss your bong water down the drain.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].