Over the past 5 years I’ve tested all sorts of potting soils, from generic brands to in-house nursery blends and even my own DIY mixes. After testing these potting mixes in my organic garden, the Pro-Mix line of potting soils has come out on top as the best organic potting soil. I now use Pro-Mix Organic Vegetable and Herb Mix in my organic garden. This Pro-Mix review explains why Pro-Mix worked better for me than the other organic potting mixes I tried.Disclosure: Since originally testing various potting mixes, I’ve received free products from PremierTech (the makers of Pro-Mix) to test in my garden. I’m not obligated to write this Pro-Mix review. I only recommend products I truly believe in.
What Makes the Best Organic Potting Soil?
When trying organic potting soil, I always look for the OMRI-Listed logo (see example below) which indicates the mix is approved for organic use. As an organic gardener, it’s important to me that I’m not accidentally contaminating my garden with chemicals. This is how I came across Pro-Mix Premium Organic Vegetable and Herb Mix. I was looking for an organic potting mix option for my container gardens and saw the OMRI organic logo.
You can look up any product on the OMRI website to see if it is listed as approved for organic use. Approved products are issued a certificate. Look up any products you’re considering using in your garden to make sure they’re safe for organic gardening.
Yes – IT’S WORTH IT TO LOOK FOR ORGANIC!
In addition to checking for organic certification, it’s important to check the ingredients. There can be a very wide range of ingredients in potting soils. Some consist almost entirely of filler ingredients (like composted lumber byproducts or manure), while others are more carefully formulated and tested to support healthy organic plant growth. The best organic potting soil has to have the best ingredients. Good ingredients lead to healthy plant growth and low potential for contamination and disease.
Most high-quality premium potting soils have similar ingredients. Good potting mix usually consists of peat moss or coconut coir for bulk volume, perlite or vermiculite for porosity (voids for air and water), and some sort of organic plant food. These mixes are often referred to as soil-less mixes as they don’t contain any soil mineral particles. Many DIY potting soils, like my own potting soil recipes or Mel’s Mix from Square-Foot Gardening, are also based on this general mix (often with compost as the plant food).
Pro-Mix Review: Why is Pro-Mix is the Best Organic Potting Soil?
So if most high-quality organic potting soils have similar ingredients, why is Pro-Mix better? The biggest difference I’ve found between Pro-Mix and other high-quality potting soil available in my area is that it includes an additional ingredient: mycorrhizal fungi.
Mycorrhizal fungi benefit your plants by forming a symbiotic association with plant roots. In a mycorrhizal system, the fungus colonizes the root tissue and stimulates increased water and nutrient uptake. This leads to increased plant growth. It’s a totally organic way to grow healthier, more productive plants.
Pro-Mix Premium Organic Vegetable and Herb Mix contains the following ingredients:
- Canadian Sphagnum Peat Moss
- Peat Humus
- Organic Fertilizer
The peat in the mix provides bulk volume, holding water and nutrients to make them available to your plants. The perlite lets excess water drain while allowing the plant roots to access oxygen. The gypsum provides calcium (very important for your tomatoes!) while the limestone neutralizes the pH of the peat moss. The organic fertilizer provides nutrients for your plants and the mycorrhizae colonize the roots to stimulate increased nutrient absorption.
More info on Pro-Mix Organic Vegetable and Herb Mix can be found on their website.
I’ve also had great results with Pro-Mix Organic Moisture Mix. It’s a variation of potting mix suited to container gardening that’s formulated with coconut coir. The coconut coir helps the soil maintain optimal moisture levels for growing vegetables and herbs in containers. Right now it’s only available for sale here in Canada, but hopefully it will go to the US soon!
My Experience Using Pro-Mix Vegetable and Herb Mix for this Pro-Mix Review
I’ve had excellent results with Pro-Mix Organic Vegetable and Herb Mix. I’ve used it to fill the larger containers in my patio herb container garden, as soil preparation in my berry walk garden, and as the top layer of soil in my new deck raised beds. I’ve used it to grow annual vegetables, herbs, and flowers, as well as perennials like blueberries and raspberries.
The mix is light and fluffy. If you pick up the bag in the store beside a bag of generic soil, it will feel lighter due to the lack of heavy filler ingredients. The lightness of the mix allows it to retain porosity in your garden, allowing roots to access air and water (without becoming waterlogged). Due to the peat content, the mix may become hydrophobic if it’s allowed to dry out completely. If this happens, soak the soil in clean water to re-hydrate it.
I also use Pro-Mix for my wheatgrass. I used to just sprout it in water, which does work, but I’ve found using a bit of Pro-Mix on the bottom leads to better production more consistent growth. It also is way more likely to survive if I forget to water it.
I did a little experiment for this Pro-Mix review with my wheatgrass trays. I found that the trays grown with Pro-Mix (pictured above, on the left) grew faster and produced more wheatgrass than those grown with out it (pictured on the right). I now grow my organic wheatgrass with Pro-Mix throughout the winter. Here’s instructions on how to grow your own wheatgrass if you’d like to give it a try.
Where to Find Pro-Mix Organic Vegetable and Herb Mix
Is it Worth It?
High-quality potting soil can be more expensive than generic options, but in my experience it’s been well worth it. I’d rather spend a bit more money up front and then have a successful garden than have to re-do work or pay to replace lower quality products. If you still don’t want to spend the money after reading this Pro-Mix review, try making your own DIY potting soil. You can recreate the mycorrhizal benefits by adding your own mycorrhizae.
Have you used Pro-Mix in your garden before? What was your experience? Have your written your own Pro-Mix Review? What’s your favourite potting soil for growing vegetables and herbs?
Love Pinterest? Here’s a pin-able image for this Pro-Mix review: