Can I Reuse Soil from a Dead Plant?

If you’re anything like me, then you probably love buying plants for your home. However, if you’ve landed on this page, chances are, that plant didn’t last too long. Before you toss it out and consider it a total loss, you may be wondering if you can reuse the soil from a dead plant.

So, can you reuse potting soil? Yes, you can reuse soil from a dead plant. However, it’s not just as simple as transferring the soil from one pot to another. This is because the dead plant depleted much of the soil’s nutrients. So while you can use it as a base, you’ll have to add vital nutrients back into the new soil either by adding compost, grass clippings, or other plant material.

Re-using potting soil

Why Did the Plant Die?

Unless you were born with a green thumb, you may not always know why your plant died. No two plants are alike, so the strategy you use to take care of one may actually hurt and hinder growth for another. A monstera deliciosa, for example, which is rising in popularity, has to be watered every one to two weeks, whereas banana trees planted outdoors need to be watered every two or three days. Watering your monstera deliciosa at the same time as your banana plant will result in overwatering and unfortunately, the end of your otherwise expensive houseplant.

Let’s take a look at the most common reasons for plant death:

Overwatering

We all learn from an early age that plants need water to survive. Though it sounds counterproductive, overwatering your plant can kill it quicker than if you didn’t water it all. When too much water is added to a plant’s soil too quickly, the water actually becomes trapped and the soil subsequently gets waterlogged, unable to drain fast enough. This constant water existence causes damage to the plant’s roots, which in turn, fails to provide the plant with the nutrients it needs to survive.

Overwatered plant

According to Doris Taylor, a plant specialist from the Morton Arboretum in Illinois, you shouldn’t water your plants on a schedule. Per Taylor, you should instead “check the actual moisture conditions in the soil, and only water when you know the soil is dry.”

Underwatering

Underwatering can cause just as many problems as its counterpart. For a plant to survive, it relies on its roots for nutrients. When a plant is not watered enough, it negatively affects the root system, so it may not develop or work properly, resulting in the leaves wilting or turning brown. Fortunately, fixing a plant that’s been underwatered is an easy fix. Just add water to the soil and your plant should perk back up in the next couple of days.

Freezing

Just like humans, plants can’t survive in ongoing freezing weather. In fact, most plants cannot survive temperatures 25 degrees Fahrenheit or under. However, generally speaking, anything below 50 degrees Fahrenheit poses a significant threat to your plant’s sustainability.

Just like how outdoor plants become accustomed to changing weather patterns, your household plants become accustomed to interior temperatures, which usually range between 65-80 degrees. When temperatures dip below this, household plants basically don’t know how to adapt, causing them to die as a result.

Whether you accidentally left your plant outside during a cold snap or it’s been perched by a drafty window, the cold winter weather can quickly kill off your plants.

Bacteria

While it may seem like a dirty word (no pun intended), not every type of bacteria is bad. In fact, some types of bacteria such as rhizobacteria are being used to promote healthy plant growth. Unfortunately, there are currently about 200 types of bacteria that cause rapid plant disease.

Think of your plant’s roots as pores. When something gets inside them, it causes inflammation or blockage. Well, the same kind of concept is at work here. Once a plant develops bacteria it will then block off the roots so the plant doesn’t get food or water.

So what should you look out for? Bacteria can kill a plant quickly, so if you notice dramatic drooping or wilting overnight, chances are it’s the result of plant disease.

Fungus in soil

Fungus

Regardless of the type of fungi you’re dealing with, they all have one thing in common: water. Fungi usually develops when there is leftover water sitting on your plant’s leaves.

This is one of those nasty side effects of overwatering, especially if you pour water over your plant’s leaves as opposed to directly in the soil. If you want to wet your plant’s leaves, it’s better to use a spray bottle to gently mist them. This will help perk them up if they’re wilted or dehydrated without dousing them in too much water which will eventually lead to a fungal disease. Remember, about 85% of all plants that develop disease end up developing some sort of fungal disease.

Insect Infestation

When you buy a plant, don’t expect that it’s going to be free from bugs. Oftentimes, these creepy crawlers make a home for themselves inside the pot or soil of your plant after crawling inside from the pot’s drainage holes. The most common insects you’ll find on houseplants include thrips, aphids, spider mites, and mealybugs. These are all very small and usually difficult to see without a magnifying glass.

If you fail to check for bugs such as these before bringing your plants inside, these insects could spread to other plants in the vicinity. This is why you should always isolate new plants for six weeks before having them join the others.

Insects eat away at the plant, ultimately weakening it, which causes it to die. In some cases, insects may lay eggs that cause damage to the leaves or stem. In other cases, some insects may carry around diseases and spread them from one plant to another.

Can You Reuse Soil from a Plant That Has Root Rot?

Root rot occurs when a plant is overwatered typically because the water doesn’t have anywhere to drain. This buildup of water essentially starves your plant by cutting off the oxygen it needs to survive. Like a virus, when one root rots, it will spread the disease to the healthy roots nearby, making root rot a very difficult thing to overcome once it’s happened.

If your plant succumbs to root rot, you can reuse the soil in a new plant, however, you’ll have to take a few important steps first, such as sanitizing it (which we describe below).

How Do You Sanitize Soil?

Though your plant may have died as a result of the common reasons mentioned above, you can still salvage the leftover soil. But first you’ll have to sanitize it. There are two common methods of doing so: baking it and adding it to a compost bin.

I’ve described these two popular methods below and what you should expect:

Baking the Soil

It sounds silly, but baking the soil is a pretty common method of sanitizing and revitalizing your leftover soil. But why? Baking helps get rid of bacteria that, if left in the soil, will negatively harm your new plant when you make the soil transfer.

To use this method, place your leftover soil in a covered, oven-safe dish and bake it between 180-200 degrees Fahrenheit for 30 minutes. Some homeowners prefer to microwave their soil instead of baking it, however, this can be a bit more time-consuming since you’ll have to cook it in intervals.

Once your soil has been baked, mix it with new potting soil that’s been sealed, as well as fertilizer to help inject new nutrients into it.

Soil in compost bin

Adding Soil to a Compost Bin

Another option is to add your leftover soil to a compost bin. Composting is the process of recycling organic matter to create new fertilizer. It often includes roots, human hair, egg shells, coffee grinds, and grass clippings, all of which, when combined, create new nutrients. Composting ultimately helps get rid of harmful pathogenic organisms and bacteria.

If you plan on using a compost bin to create new soil for your plants, expect the process to take about two weeks to complete from start to finish.

How Long Does it Take Plant Roots to Decompose?

The answer is that it depends. While tree roots can take up to seven years to fully decompose, the decomposition rate for plant roots is typically no more than six months if they’re properly composted.

As mentioned above, compost is the simple process of recycling food and organic matter into fertilizer. Even if your plant died, there are still some valuable nutrients left over that will be beneficial to the compost and resulting fertilizer.

How Long is Potting Soil Good For?

Generally speaking, a bag of potting soil is good for about six to 12 months if it’s stored in the right temperature and environment.

Unlike plants that may not enjoy cooler temperatures, potting soil remains freshest when it’s put inside a cool, dry place. However, this only applies to bags of soil that have been unopened. If you’ve previously opened your bag of soil and are looking to store leftovers, make sure to put it in an airtight container.

Think of storing soil the same way you would your canned goods. Unopened canned goods in your cabinet can usually last for up to a year. However, as soon as they’re opened, they’ll spoil if you put them back in the same environment. Your plant’s food is the same way.

Final Thoughts

It’s always upsetting when a plant dies, but you don’t have to panic or feel like you’re wasting money when that death occurs. You can still breathe new life into a new plant by reusing the leftover soil. With these tips, you have plenty of ways to keep your garden going.

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