Learn how to make your own soilless potting mix at home! Commercial bagged soils are pricey, and if you use a lot, can add up to significant costs. They also vary greatly in quality and, in some cases, their fertilizer strength can be toxic to plants and cause burns to plant roots. It’s satisfying to make your own mix to give your plants a healthy start—and it leads to fewer headaches. Here’s our basic DIY potting mix recipe.
Containers are great for several reasons—they’re versatile and space-saving, and they allow you to be more efficient in your use of resources. If you have a small garden space or live in an apartment with a balcony or rooftop, containers are for you.
What Is Potting Mix?
For containers, you’ll often read that you need to buy or make a good potting mix. But what does this mean?
Potting mix is not garden soil—which is heavy and includes sand, clay, and other cheaper additives that won’t work for containers. Some people may refer to it as potting soil, yet potting mix is soilless. It’s lighter and fluffier than ground soil to allow enough air and water for healthy root growth and also provides enough anchorage for roots. These soilless mixes are sterile, so there is no chance of introducing pest or disease problems.
Potting mix can certainly be bought in bags at garden stores. Look for “Soilless Potting Mix,” which generally includes three ingredients: 1) peat moss or coconut coir for moisture and nutrient retention, 2) pine bark for anchorage, and 3) either perlite or vermiculite for air space, which makes the texture light and fluffy. Some potting mix also includes fertilizer or moisture-retaining treatments. If you use a potting mix with fertilizer, you’ll need to adjust the fertilizer you provide. (Think of salted butter versus unsalted butter in a recipe!)
But many gardeners who plant a LOT of containers or raised beds or start seeds indoors will mix up their own potting mixes! For the number of containers I use in my garden, I learned long ago that it’s much cheaper to make my own potting mix and store it in an extra trash can rather than pay for several big sacks of premade potting mix. Plus, I can customize the mix for a variety of different plants.
Before Making Your Own Potting Mix
Before we go any further, note that if you only need a few small containers’ worth of potting mix, you may actually be better off buying a premade mix! Making your own is usually only economical on a large scale. Here are a few things to keep in mind before creating your own mix:
When it comes to any potting mix, the lighter it is, the better. Loose and porous mixtures not only make a container lighter to move, but they also transport water, fertilizer, and air to plant roots more quickly and allow for good drainage, which is important for container gardening.
Start with the basic recipe below and then add soil sulfur to lower the pH or lime to raise the pH, according to the needs of your plants. Both additives can typically be found at garden centers. Plants such as lettuce, Russian sage, and marigolds prefer sweet soil with a pH of about 7.5, while others are acid lovers, like ferns, asters, and strawberries. They need a pH of about 5.5 to 6.0. Here’s a list of more plants’ pH preferences.
If rapid drainage is needed, as is the case for cacti, succulents, and lavender, add extra sand and perlite.
If greater moisture retention is needed, as is the case for ferns and woodland flowers (like primrose) add extra vermiculite or coconut coir.
Potting mix is sold by volume (typically measured in quarts), and most pots are measured by their diameter. To translate quarts of mix into various pot sizes, use this quick reference:
<a title="View user profile." href="/author/editors">The Editors</a>Fri, 10/27/2017 - 13:03
There are several plants known for cleaning the air. Learn more here: https://www.almanac.com/blog/gardening/gardening/houseplants-clear-air and here: https://www.almanac.com/blog/gardening-blog/clean-house-tropical-plants
Some plants may be named on both of those pages but that just makes them doubly good!
Best wishes!
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<span>Eric</span>Mon, 08/28/2017 - 13:43
I recently acquired 100 bags of cheap potting soil which i used this spring, i haven't had much luck with it. Is there anything i can mix with it to upgrade? thanks
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<span>Chris</span>Mon, 09/18/2017 - 22:41
I typically always mix in some peat moss and perelite to make it a bit loser, if the problem you are having is it being too compacted.
Peat moss always is a key ingredient even if you don't have the perelite. Hope this helps.
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<span>Anna</span>Thu, 07/13/2017 - 23:23
I would like to know which herbs and vegetables (salad reens, tomatoes, carrots, mushrooms, celery) I can successfully grow inside my home since I do not have a garden. I plan on making your homemade soil recipe.
I currently live in northern florida (yulee) and I keep the temperature at about 76°F. There is a decent amount of sunlight coming in through my glass porch doors which is where I keep my only successful indoor plant: basil.
Do you recommend any specific pots/pot size as I don't want to end up with plants that require huge pots as they grow.
Any help is appreciated.
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<a title="View user profile." href="/author/editors">The Editors</a>Mon, 07/17/2017 - 09:43
Hi Anna, thanks for writing! Your house temperature is perfect, so don't change that. You can grow a few plants with sunlight from a window, but most vegetables are going to need strong, direct light to grow well. A low-energy grow light suspended 2 to 4 inches above your plants is the best way to grow veggies indoors. For recommendations on growing salad greens indoors, try here: https://www.almanac.com/blog/natural-health-home-tips/grow-your-own-salads-indoors-all-winter. For pot size, it all depends on the vegetable: Tomatoes are going to need at least a 12-inch-wide by 12-inch-deep pot; kale or spinach, green onions, and celery will need a shallower pot, but just as wide; and carrots will need a pot at least 12 inches deep, but any width (depending on how many you would like to grow). When growing indoor veggies, remember to feed the soil an organic fertilizer, like fish fertilizer, every 3 to 4 weeks to keep the plants strong, happy, and healthy. Good luck, we hope this helps!
My first time with any tree. Wanted to know the mix/ratio to transplant my cherry tree in a 20 gal container. Basically, what is needed from bottom to top? Thank you in advance.
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<a title="View user profile." href="/author/editors">The Editors</a>Mon, 07/10/2017 - 21:37
Add a layer of gravel or rock to the bottom of a container that has drainage holes. Then, add some potting soil for the roots to rest on. Add the tree, and then the rest of your soil.
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<span>Ed Feyl</span>Mon, 06/05/2017 - 16:19
Hi,
Can I use coffee grounds to a potty soil mixture? If so what do mixture ratio do recommend?
Respectfully,
Ed
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<a title="View user profile." href="/author/editors">The Editors</a>Mon, 06/05/2017 - 22:04
To us, coffee is best used to amend soil over the long-term to improve soil structure. We would use sparingly, with no more than 20% of the total mix. Mix into the soil to make nutrients more accessible to the plants.
There are several plants known for cleaning the air. Learn more here: https://www.almanac.com/blog/gardening/gardening/houseplants-clear-air and here: https://www.almanac.com/blog/gardening-blog/clean-house-tropical-plants
Some plants may be named on both of those pages but that just makes them doubly good!
Best wishes!