It’s Time to Make Your Own Potting Mix

Your monstera is rapidly outgrowing its nursery pot. Or maybe you suspect that your pothos—the plant everyone said would be so easy to care for—is suffering from soggy roots. Or your aloe will not stop sprouting offshoots. If this sounds familiar, your plant is due for some routine maintenance. Wiggle that plant out of its pot, inspect its roots, and get it ready for some fresh potting mix: It’s time to repot.

While this task is met with a healthy mix of eagerness and dread, depending on your tolerance for dirt getting all over the floor, it’s something that every responsible plant owner has to do sooner or later. But before you buy potting soil, let’s take a step back: It’s high time you made your own potting mix.

Plant consultant Tyler Cross credits his thriving plant-filled home to his use of DIY mixes. "You can create a soil that has more air pockets. They help your roots receive oxygen, which is critical to their health," he says. "On top of that, it allows you to customize and add things that can give your plants an extra advantage."

In addition, Cross warns that store bought potting soil alone will likely retain too much moisture, noting that waterlogged roots can lead to root rot, a condition that will kill your plant if left untreated.

Susanne Zirkiev, a digital creator and plant stylist who shares her extensive collection on Instagram and TikTok, told Dwell that this is because traditional potting soils are generally designed for outdoor container plants. 

"They lose water a lot faster [than indoor plants] because it’s hot and sunny," says Zirkiev. "So they’re usually more water-retentive than what you want in your home."

Zirkiev’s preferred DIY potting mix starts with one bag of Fox Farms Ocean Forest Potting Soil, which she described as one of the few indoor potting mixes she’s used that is well-draining on its own. She then adds perlite, a granular material made of volcanic glass, for additional drainage. Finally, she adds horticultural charcoal to help roots absorb nutrients, and orchid bark for some extra chunk.

"None of us have the money to buy a plant, kill it, and have to buy another one over and over again," says Zirkiev. "I am a firm believer in, if you know what’s going to work to help the longevity of your plant, then just do it."

Variations of this combination is what you’ll typically find when you research DIY potting mixes, especially on TikTok, where some plant influencers make their potting mixes as elaborate as a mole recipe. But many of these popular mixes are a little decadent for Nick Alexander, a plant YouTuber who combines plant care science with humor. 

"Simple soil mixes are better because there are less variables to sift through if something has gone awry," says Alexander. "There are a few roles soil must carry out: aeration, moisture retention, and nutritive capacity. Generally, you only need one constituent to cover each requirement, which is why I don’t use an elaborate soil mix."

His DIY potting mix of choice: a 80:20 mix of Premier Peat Moss and perlite, adding half a cup of Espoma Garden Lime lime for every 10 quarts of soil to balance out peat moss’s natural acidity. Peat boasts some serious water retention and doesn’t compact and put pressure on the plant’s roots, but it lacks the natural nutrients of traditional soil, so plant fertilizer must be added. (Don’t look at this as a pesky step: even soil-based plants require fertilizer to truly thrive.) 

While some quibble over peat due to the fact that it’s non-renewable, Alexander prefers it because it isn’t prone to decay, unlike bark-heavy soils. Decaying material in your plants can encourage mold, fungal infections, and attract the bane of every plant owner: fungus gnats.

"Ancient men have fallen into peat bogs, only to be unearthed two millennia later, better preserved than Egyptian mummies," Alexander says. "Ultimately I don’t like decayed philodendrons and I’m going to continue repotting with my environmentally indifferent bog slop.

He also wants to remind the peat-hesitant that pumice, perlite, and lava rock aren’t renewable either. "That is," he says, "unless you know how to spawn volcanoes from the Earth."

But much of this advice is best suited for tropical houseplants. What should the succulent and cacti fans do?

"Go gritty," says Christian Summers, one of the owners of Tula House, a plant nursery in Brooklyn, New York with an impressive array of arids.  

"At Tula House, we start most mixes with a base of PRO‑MIX BX, which is a favorite in the grower world for its base quality of drainage, aeration, fibrous matter and Mycorrhizae, which are organic matter (nutrients) creating a symbioses between a mycorrhizal fungus and roots," says Summers. "It accelerates rooting, improves fertilizer uptake and increases resistance of plants to stresses… From there we will amend and build the soil structure based on the type of plant we are potting."

But you don’t need to cop the Mercedes of potting soil to successfully repot your jade plant.

"Buy a cactus or succulent specific soil, but if you can’t find that or want to amend an all purpose mix, then add rocks, sand or perlite to build aeration, drainage and stability in your soil," says Summers. "For arid mixes, we like to use the test of squeezing the soil in one closed hand. When you reopen your hand the soil should fall apart. We call this the ribbon test. If the soil is sticking together after opening your hand, that means there is too much moisture retaining matter in the soil and you should add more rocks, sand, and grit to break it up."

No matter what route you choose in your DIY potting mix adventure, don’t assume you’ve formulated the best combo for your plants until you’ve actually watered them. Water your plant thoroughly after repotting and—most importantly—make sure water drains out of the bottom. If the plant is struggling to drain water now, it’ll likely still struggle in a week or month down the line. It can be a hassle to add more drainage elements after the fact, but it’s better to adjust while your hands are already dirty. The last thing you want is to pat yourself on the back after repotting your favorite plant, only to find it turning black a couple of days later thanks to root rot, courtesy of your not-so-well-draining-after-all-whoops potting mix.

Like everything in plant care, this is all hit or miss with a learning lesson thrown in. Above all else, whether you’re using 10 different ingredients in your mix or just two, listen to your plants. They’ll let you know if they’re happy or not.

Photo by Pär Olofsson