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Brown Runoff From Plant Pot: (Causes, Prevention & Cleaning tips)

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Potted plants add colors and freshen the air in our houses. At times these potted plants when watered, can cause a mess, especially when there is brown runoff coming out of the pot.?

The brown runoff from potted plants is mainly due to the constituents of the soil. In most cases, the soil will consist of decaying organic matter such as oak leaves, clay, or composted manure which all can turn the water brown as it runs through and out of the soil. This brown runoff can stain floors if it is allowed to sit for too long.

The brown runoff from the plants can leave stubborn and ugly stains on your patio. 

If you too are struggling with brown runoff this article will explain what causes the brown runoff and how you can prevent it from causing a mess.?

If you are going to repot your plant, there are many good soil options out there, but I have found this potting soil made by Miracle-Gro from amazon to be the most affordable and effective in keeping my plants healthy long after repotting.
You can find it by clicking here.

Miracle Grow Potting Mix

What Causes The Brown Runoff From Plants When Watered?

what causes Brown runoff from plant pot

Brown or rusty runoff after watering can be caused by a number of reasons. A few of them are described below:

Homemade Compost Containing Oak Leaves

Tannin in oak trees can cause brown runoff. Tennin is a water-soluble polyphenol that according to the U.S Department of Agriculture (USDA) may help improve soil quality.

Because of its various benefits, gardeners mostly use oak leaves in their compost. 

If you, too, are using oak leaves in your compost mulch then it can be the main culprit for brown runoff. 

To Fix It:

To stop the brown runoff, re-pot your plant. However, don’t use oak leaves in your compost mulch this time. 

If you don’t want to re-pot, water copiously until you see the water coming out a lot cleaner.

After you see clear water coming, place the pot in a saucer or pot to drain excess water to prevent root rot. 

NOTE: To prevent the stubborn brown stains, use a solution of bleach and one-gallon water.  

Composted Manure

Composted manure can also cause brown runoff. If you have added even a small amount of composted manure, it can cause rusty or brown runoff.

Fertilizer Residue or Salt Buildup

Fertilizer residue and salt buildup can also cause brown or rusty runoff. 

Over time, minerals in water can get accumulated around your roots at the bottom of the pot.  Therefore it is recommended to use water from a clean source when watering plants. 

The water with which you water your plants can affect your plant in many ways including this brown runoff. 

The same is the case with the chemicals in fertilizers. If the fertilizer you are using contains Manganese, iron, or copper, it might be the cause behind brown runoff.  

To Fix It:

To fix the salt/mineral/fertilizer build-up, flush your pot thoroughly with distilled water. Hopefully, after three or four flushes, your pot will have a clearer runoff.

Adding fertilizer while misting is also an effective way to ensure that the soil does not have excess salts which can build up over time.

Other Organic Components in The Potting Soil

Organic components in the potting soil can also cause brown runoff. Give a thorough wash and the problem will get fixed. 


Another common cause behind brown runoff can be overwatering. 

Generally, the most common problems plants face are overwatering and underwatering. Some gardeners love watering their plants, especially beginners. 

With dry soil, it?s easy to rush and pour more water than is required in the pot.

When you overwater your plant, a big part of the water gets settled at the bottom of the pot near the roots, resulting in root rot and plant death. 

To Fix It:

To prevent wet feet and brown runoff, place some rocks at the bottom of the pot.

The rocks help with drainage at the bottom of the pot as there are large pore spaces that prevent water accumulation. 

Garden Soils

If your plants are potted in garden soil, the water drains as brown (dirt + water = brown runoff).

This brown color is attributed to different forms of rocks, minerals, plants, and animal remains.

To Fix It:

You can water your plants with the bottom watering technique to prevent brown runoff. 

I use this Miracle-Gro Potting Mix from Amazon, which ensures my plants stay healthy long after repotting. Take a look and compare it to other potting mixes.

Miracle Grow Potting Mix

How To Keep Plants With Drainage Holes From Making a Mess?

You can minimize the effect of the potential mess caused by potted plants by using plant saucers. 

A plant saucer is a kind of deep plate that gardeners place beneath their plant pots to ?capture or catch? drained water from the pots. 

Plants don?t utilize all the water that you give them, a large part of it gets drained out of the drainage holes at the bottom of the plant pot. 

A saucer is what keeps that water from spilling and creating a mess around your floor. 

The brown runoff draining from the drainage hole will be collected into the saucer and then can be removed by different methods. 

The Benefits of Having a Plant Saucer:

Plant in saucer

Plant saucers are usually used with plant pots or containers to ?catch? and hold excess water which has drained out from the plant after it has been watered. 

The saucer will hold the brown runoff and prevent it from staining your patio or floor. 

Most plant pots usually come with saucers but if you have to get one I would suggest finding one that matches the pot and could hold a sufficient amount of water.

Holds The Excess Water

Using saucers on plants for both indoor and outdoor applications can prevent a brown runoff mess whenever the plant is watered. 

This is because every time you water your plants, the brown runoff will drain into the saucer through the drainage hole and hold within the saucers.

After that, you can simply remove the dirty water from the saucer. By removing the extra water from the saucer, you can prevent staining your floor. This water can be re-added to the plant to recycle leached minerals from the soil.

See our detailed post on removing excess water from plants saucer.

Prevent Insects From Nesting

You can prevent the ants from harming your plants by creating a water barrier between them and your plants. 

Insects can dramatically damage your plant leaves and soil mixture. Plant leaves are a good source of food for bugs, spider mites, and other insects. 

Some of the insects (e.g. snails and ants) even lay their eggs in the potting soil. A little negligence from your side and your plant will be invaded by an army of insects. 

Increase Humidity

In addition to creating less mess in the house, saucers are also a great way to increase humidity for plants. 

The plants that need more humidity to thrive will grow best in the pot along with a plant saucer e.g., Birds nest fern. 

Add some stones and pebbles to the saucer and then pour water into it, in this way a good humidity will be provided to the plants.

How To Clean Plant Stains From The Floor?

There are a number of ways to remove the stains from the floor caused by the brown runoff from your plants. 

Stains From Fertilizer Residue

The stains caused by fertilizer residue (containing copper manganese, or iron) usually leave bluish-green or brown stains on the concrete floor. You can remove these stains in the following ways:

  • Vinegar, Flour, and Salt:

    Make a paste by mixing four cups of white vinegar, one teaspoon of salt,  and flour.  Apply the mix on the stains and let it sit for 30 minutes to one hour. 

    Thoroughly rinse with warm water and gentle scrubbing. 
  • Baking Soda, Lemon, and Salt:

    Dissolve one teaspoon of salt in two spoons of lemon to make a paste. Rub the paste with a soft cloth or brush. 

    Wait for a few seconds and rinse with lukewarm water and dry. 
  • Soap and Warm Water:

    If the stains aren’t stubborn, simply scrub them clean with warm soap and warm water. 

If you want a slow-release fertilizer that will ensure your plant grows healthy for a long time with minimal intervention, I recommend Osmocote Smart-Release Plant Food.

Osmocoat fertilizer

In Case of Dirt, Salt, or Mineral Build-up

If the stains are caused by salt or mineral runoff, use the following ways:

  • Bleach and Water Solution:

    Mix a little amount of bleach with one-gallon water. Gently scrub the floor and rinse it with lukewarm water. 
  • Vinegar and Paper Towel:

    Mineral deposits on the concrete floor can be softened and removed by covering the deposit stains with vinegar-soaked paper towels for at least one to two hours. 

    Rinse with warm water and dry.

The Takeaway:

To conclude, the brown runoff from the plant pot can be caused by a number of reasons including, salt/mineral build-up, fertilizer residue, composted manure, homemade compost mulch containing oak leaves, garden soil, or overwatering. 

You can prevent the mess created by brown runoff by using a plant saucer. 

A plant saucer will capture all the dirty excess water drained from the pot and keep your floor stainless. 

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