2017 Potting Soil Challenge

Potting Soil Challenge; Seedlings; Seeds; Indoor Garden

2017 Potting Soil Challenge

The 2017 Garden Season is in full swing at the Small Scale Life Headquarters!  I broke out seed trays and containers, seeds, potting soil and trusty GoPro and got down to business.  As I had mentioned in the How to Garden Indoors post, I wanted to test different soils this year.  I purchased three potting soil mixes for this test: Master Gardener, Pro-Mix and Burpee Coir.

Master Gardener and Pro-Mix Potting Soils

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There are many options when it comes to soil. Time to test some soil this year!

I wanted to test two commercially available peat moss-based potting soils this year.  The two soils I selected were the Master Gardener Premium Potting Mix and the Pro-Mix Organic Mix.  Both soils were available at Menards, which is close to my house.  I grabbed to seed flats and loaded them up with the soils.

One of my biggest pet peeves with commercially available peat moss-based soil mixes and compost is the garbage mixed in the soil.  I have found rocks, sticks, pieces of plastic, toys and mats of peat moss in the soil.  Not wanting a bunch of debris in my seed trays, I always remove this material, particularly when finding this junk in my potting mix.  For this test, the Pro-Mix had less debris in the potting mix.  Advantage: Pro-Mix.

I would also caution gardeners about the cheap bags of “compost” offered at some big box stores.  I have seen these bags loaded with clay, which becomes clumps when wet and rock hard clumps when it dries.  Nothing is worse!  Spend a couple extra dollars for better soil!

As a sneak peak of the Week 2 Indoor Garden Update, both mixes are doing about the same in terms of seedling growth.  I have had good germinations from the red peppers and tomatoes and marginal germination from lettuce in both flats (they are about tied).  Neither flat is generating many green peppers and jalapeno peppers.  Go figure!  Peppers!  GRRR!

The jury is out on which of these two mixes is better, but on debris alone, Pro-Mix is the leader.


Potting Soil Challenge; Seedlings; Seeds; Indoor Garden; COIR

I am trying Burpee’s Coir Seed Starting Mix. Add water to one brick, and you will get 2 gallons of potting mix

As I discussed in the How to Garden Indoors post, this is the first year I have ever used Coir Potting Mix.  Coir is Natural Coconut Fiber that is made from ripe coconuts.  It is actually the fibrous material between the hard, internal shell and the outer shell of the coconut.  I purchased a block of Burpee Coir this year, and I wanted to test it out compared to the more traditional peat moss-based potting mix.

To use Coir, you place the unwrapped brick into a bucket and simply add two quarts of water.  The Coir material soaks in the water and expands to two gallons of useable potting mix.  Compared to the other two soils, Coir was uniform material without any sticks, rocks, plastic or matted peat moss.  I really liked using this material, and I will be using this material when I teach basic gardening at two elementary schools this month.  I won’t have to lug in a tote full of potting mix!

As seen in the video below, I had some excellent results with the Coir potting mix.  I had greens germinating and popping through the soil in three days!  That was a record for me.  Of course, it isn’t quite a fair test since this Coir flat has greens and herbs, not tomatoes and stubborn peppers.  Still, I am impressed!



What’s Your Potting Soil?

So far so good in the indoor garden, and I am really impressed with Coir!  I am curious: what are you using for potting soil?  How is it working out for you?  Did you experience any damping off disease with your seedlings?  I would love to hear your stories and experiences!

5 Comments on "2017 Potting Soil Challenge"

  1. Hi Tom, I’ve been on the same journey a few years ago and wasted a LOT of time and money growing ‘dried arrangements’ with bagged mixes (from the cheap to expensive). I decided to experiment making my own nutrient-rich, moisture-holding potting mixes and seed raising mixes. I learned an immense amount along the way and have made tonnes (literally) of my own organic soil mixes over the years and started sharing it with friends and on my website. I just thought you might find my experiences useful from someone who’s walked in the same shoes! I wrote an article about the pros and cons of using bagged mixes (which may save you some money) and it has a free recipe I hope you find helpful. http://themicrogardener.com/easy-diy-potting-mix. All the best on your journey. Warm regards Anne

    • Thanks for the comments, Anne! I really like your article and “recipe” for potting mix and soil mix. I just noticed today that you are offering a guide for making the mixes as well! I will have to check that out. Yes, having great soil is an essential building block to growing great plants, and I like your use of vermiculite, coir and worm casings/compost. That is a SOLID soil, and I can see using that in my future gardens. Seriously, this IS that good. Question for you: do you find that the pH meter shown in your article is pretty accurate?


      • Hi Tom, I use a different pH Meter but it is really useful though not as accurate as a kit. I also use a kit [http://amzn.to/2orJ86l] to test my soil every few months, which is a bit more expensive but more accurate. I would also suggest you take into consideration the TIMING of your seeds germinating. It’s not just the mix and soil moisture that affect seed germination. There are many other factors including the moon phase. If you sowed your herb and greens seeds in the new moon phase, this makes a HUGE difference to fast germination. The gravitational pull of the moon at that time of the month, helps seeds swell faster. If you sowed right now, in the dormant phase, it would be unlikely you’d get the same results in the same mix! So when running an experiment, just be aware that it’s not just the soil mix that is affecting germination. It can be the seed viability, soil moisture, temperature, light, humidity, moon cycle etc. In the seed raising mixes that I make, I add extra ingredients as ‘insurance policies’ to swing germination in my favour. Anyway, hope you find this helpful. Cheers Anne

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