Container vegetable gardens are the versatile champions of any garden. I love container gardens because you can start them indoors and transition them outdoors without disrupting the vegetable roots. They’re ideal for small spaces, porches, balconies, and even that sliver of side yard you might have that gets great sun exposure but is too small for a garden bed. The key to a successful container garden is your potting medium. There are many different store-bought varieties of potting soil and potting mix, but in my opinion, the best potting soil for container vegetables is a hand mixed.
Not only will you save money, but you’ll be able to tailor mix your potting soil based on the type of vegetables you are planting in it. You’ll also never wonder what is in your mix since you hand-selected all of its ingredients.
I know it seems like overkill, but mixing potting soil and potting mix is just like any other science experiment and safety is important. To avoid the risk of exposure to bacteria that may be living in your potting mix ingredients, it’s a good idea to wear a protective face mask and safety goggles. This will help you avoid inhaling dust and other organic particles. Gardening gloves and protective clothing are important too, to prevent skin irritation. Of course, it probably goes without saying that good hand washing routines before and after gardening are an important step at protecting yourself and your loved ones from any bacteria and allergens.
Potting Soil or Potting Mix?
You may notice the terms “potting soil” and “potting mix” used interchangeably at your garden store, but there is a difference. Simply put, potting soil contains dirt and potting mix doesn’t. The challenge with using potting soil for container garden vegetables is that too much dirt can create too compact an environment for vegetable roots to grow. Compact soil can also deter air and water circulation.
The key to successful potting mix and potting soil for container vegetables is making sure there are other elements added to keep your mix light and airy while still retaining moisture and remaining nutritional.
Here are some elements (and their recommended proportions) to consider adding to your homemade potting soil for container vegetables:
Mature Compost (2 parts)
Homemade compost is ideal if you have it, but you can also purchase organic compost. The key to prepping your compost for potting mix for container vegetables is passing it through a sieve of some kind to remove larger chunks from your mix.
Coconut Coir or Coir Peat (1 part)
Coco-coir, Coconut Coir, or Coir Peat is all the same thing and is a great, eco-friendly peat product made from the husk fibers of coconuts. Regular peat moss has some not-so-eco-friendly harvesting practices which should be considered before use. The trick with coconut coir is to pre-soak for at least 15 minutes before pulling apart and adding to your mix. Coco coir is a great moisture retention element in your potting soil for container vegetables, and also allows for good air circulation.
Vermiculite and/or perlite (1 part)
Vermiculite and perlite are super lightweight puffy particles derived from volcanic rock and have great water-retaining qualities. Naturally non-toxic and sterile, vermiculite and/or perlite are a great addition to your potting soil for container vegetables. Look for Grade 3 which is particles of approximately 3-6mm in size. Vermiculite and perlite are great ingredients in potting mix for container vegetables since they promote quick root growth and help anchor new roots. You can swap out vermiculite and perlite for sand if you’d like, but be sure to use garden-grade sand and not construction or play sand, since those have impurities like salt that can affect your potting mix.
Worm Castings (1 cup-ish*)
If you do your own worm composting, then you’re ahead of the game, here! You can buy worm castings as well. Worm castings are rich in minerals like potassium, magnesium, phosphorus, and calcium. They also help vegetables and other plants retain moisture.
* You really can’t use too much worm castings. It won’t damage your plants. You can even sprinkle worm castings around the base of your vegetables when they sprout from your containers.
Other nutrients/additives for potting soil for container vegetables
You can add fertilizers and other minerals while you’re mixing your batch of potting soil. You could also wait and add as needed depending on the types of vegetables you are planting. Adding them all at once saves you time. Waiting to add what you need will allow you to tailor the potting mix to the specific seed or seedling. It really depends on what type of vegetables you are planting and whether you are making a larger batch for storage.
Test, plant, and store
Once your potting soil for container vegetables is mixed, check the pH with a meter or testing kit. Then check it again in a few days. After that, you’re ready to plant vegetable seedlings or seeds in your containers. Store your potting mix for container vegetables in something with a well-fitted lid that can help reduce moisture loss.
Do you have a tried-and-true potting soil or potting mix recipe that you use for your container vegetables? Share it in the comments!