How Do Weeds Grow in Indoor Pots? 5 Ways

We all know that weeds are annoying, unpleasant to look at, and can harm your plants. If you thought your plants indoors were safe, you would be mistaken. Indoor plants can still have weeds. 

Putting your plants and empty flower pots outside can cause weeds in indoor plants. Watch out for hitchhiking seeds, and make sure you buy soil instead of using dirt from your backyard. Using a weed and fungus preventative is the best way to keep weeds and mushrooms out of your indoor plants.

In this article, I will discuss the five ways weeds can grow in indoor plants. Read on to learn what you can do to prevent this from happening.

Understanding Weeds and Their Impact

Weeds are invasive, unwanted plants that come in a variety of species. By definition, weeds are plants growing in an area in which they are not wanted. If left unaddressed, they can easily take over your garden or yard. 

Weeds are very competitive and will take over wherever they may be growing. The reason weeds are so unwanted is because they take space, water, nutrients, and sunlight from other plants that you want to keep in your garden. Weeds are known to suck up nutrients from the soil, such as potassium and nitrogen. 

Weeds grow and multiply extremely fast, making them even more challenging to get rid of. They tend to have deep roots that are hard to get entirely out of the ground.

They can even be camouflaged in your garden; some look like regular—even pretty—plants. Once you realize they aren’t, it’s too late, and they’ve taken over your whole garden.

Weeds are also known hosts of several insects and crop diseases. Some weeds produce toxic chemicals that disease your plants and the surrounding soil. 

The Five Ways Weeds Can Invade Indoor Plants

In order to protect your indoor plants from weeds, it’s essential that you understand the key ways weeds can grow in indoor pots:

1. Putting Plants Outside Can Cause Weeds Inside

Weeds commonly come from the grass outside, and they can travel using the wind and bugs. If you buy your plant from a store that keeps many plants in a gated outside area, they may start to show signs of weeds, even after you have placed them inside your home. 

Since the plants were outside, it is very likely spores from weeds got into the plant. By the time the plant reaches your home, the weeds have already spread their roots, and soon you’ll be seeing weeds in your indoor plants. 

If you sometimes take your plant outside to help it dry out or get more sun, the same situation can occur. So, always be careful about your indoor plants going outside. Try to find a good spot in your home for sunlight so that you don’t need to put your plant out. 

When buying a plant from a store, keep a very close eye on it for the first week or two. If you notice any weeds growing, you can put a stop to them before it’s too late. 

2. Pots Stored Outside Can Harbor Weed Seeds and Spores 

The outside is the main culprit of weeds because weed seeds and spores can be anywhere in the air or transported by insects. If you purchased a plant but transferred it to a flower pot you already had, this could be the origin of weeds in your indoor plants. 

If you stored the flower pot outside, weed seeds could have easily been blown into the pot. So, if you did not thoroughly clean the flower pot before transferring the new plant over, then you just gave those weed seeds a brand-new home. 

Even if you see nothing and believe the flower pot is fine, always wash it out first, just in case. There can also be fungi or tiny insects living in the flower pot, just waiting for a host.

You can easily rinse the flower pot and wash it with regular soap and water. Just make sure you rinse all the soapy water out before putting the plant in the pot

3. Hitchhiking Seeds Turn Into Weeds

The heading of this section was no mistake. There are such things as hitchhiking seeds.

These seeds come from various weeds and can stick onto clothing and your pet’s fur. They have sticky spikes that help them attach to things, but they can fall off after a bit. 

A hitchhiking seed can make its way into your home in a few simple ways:

  • You took a walk outside, and the seeds stuck to your clothing.
  • Your dog rolled around in the grass and picked up stray seeds.
  • You were gardening and happened to touch weed seeds.

Approximately 600 weed species travel by hitchhiking, and 248 of those are considered invasive.

Here are some common examples of these invasive species:

  • Harpagonella
  • Bidens
  • Krameria 
  • Calico Aster
  • Hedge-parsley
  • Sandbur
  • Common burdock

These seeds can be very tiny and look just like random pieces of grass or plants; if you see them, you may think nothing of it. Sticking is how the hitchhiking seeds get you.

They either go unnoticed and fall off into indoor areas—including your indoor plants—or you think they’re harmless and brush them off, causing them to fly into other places. 

Hitchhiking seeds can also stick to your pets; if your dog comes from inside with seeds on his tail, they can easily fall off into potted plants. It may be good to keep potted plants at a higher level to avoid this issue. 

4. Using Dirt From Your Backyard Leads to Weeds

Any experienced gardener knows that soil is an important part of the potting process. Some people may think that getting dirt from outside is the best option—it’s just dirt, and it’s free, right?

Wrong. Using dirt from outside can result in various unwanted seeds getting into your potted plant. 

Another reason you don’t want to do this is that plants need nutrients. When you buy bags of dirt, they come with nutrients and plant food already mixed with it. These keep your plant extra healthy and ensure it has everything it needs to thrive. 

If you don’t feel like going to the store, you can also buy potting soil at your garden center or online.

5. Failure to Take Preventative Measures Can Allow Weed Growth

Even if you don’t think you’ll get weeds, it’s essential to use a weed killer that is also preventative. It is also an excellent idea to spray weed killer in the flower pot before putting a new plant in it, just in case there are some leftover seeds or spores in the pot.

A weed killer is also suitable for those pesky hitchhiking seeds I explained earlier. It should do the trick if you see those start to sprout up.

Monitor Plants Carefully for Weeds and Mushrooms

Some of the unwanted life that may sprout up in your indoor plants aren’t weeds but may be just as annoying. Believe it or not, mushroom growth in potted plants is a common problem. Mushrooms grow as the result of a fungus being in your plant. 

The leading cause of this happening is using a contaminated soil mix to plant with. Sometimes, the bags of soil can be contaminated with a fungus before it gets to the store you purchase them from. 

Another issue, just like with weeds, occurs when spores get on clothing and then fall off into potted plants. Then, mushrooms will start to grow before you know it. Finding mushrooms in your indoor house plants is likely to happen in the summer when it’s warm and moist.

If you end up with mushrooms invading your home, it is hard to get rid of them; unfortunately, the fungus is dispersed throughout the soil. Mushrooms usually don’t cause harm to you or the plant, but they sure are annoying.

Here are a few tricks you can try to get rid of the mushrooms:

  • Remove the mushrooms manually.
  • Scrape the top two inches (5.08 cm) of the soil off.
  • Completely change out all soil.
  • Drench the soil with fungicide.
  • Change the pot’s environment to a cool, dry area

Final Thoughts

When it comes to preparing to pot indoor plants, it is important to remember not to store your plants or empty pots outside. Watch out for hitchhiking seeds because they can stick to almost anything, and there are hundreds of species of them.

Don’t use dirt from your own backyard, as this is a sure way to get unwanted seeds in your potted plants. Use a weed and fungus preventative to keep the weeds and mushrooms from sprouting. If you follow these few suggestions, you will be able to keep your indoor plants free of weeds.

Dr. Moritz Picot

Dr. Moritz Picot is a horticulture enthusiast and the founder of, where he serves as the lead content writer. He established the website in 2022 as a valuable resource for both gardening aficionados and beginners, compiling all the gardening tips he has accumulated over the past 25 years. Alex has a passion for nurturing plants, transforming backyards into inviting spaces, and sharing his knowledge with the world.

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