Miracle-Gro Potting Mix Review for Slow-Growing Microgreens

Is Miracle-Gro potting mix a good choice for slow-growing microgreens? In this Miracle-Gro potting mix review, we test how well basil microgreens (a slow-growing microgreen) grow in two different potting mixes.

The reason another soil is tested against the Miracle-Gro potting mix is that we need a control to see if there are any differences in growth rates, color, and overall health of the microgreens.

The Home Microgreens Potting Mix is a good control as I have documented how well it grows microgreens against other popular brands of potting mix and other grow media.

This Miracle-Gro Potting Mix review is the second article in a two-part series reviewing how well it grows microgreens.

This Miracle-Gro potting soil review will also include links to other articles listing the ingredients in the potting mix. The related articles describe and explain each ingredient, how it is formed or sourced, and if they harm you or the environment.

In part one of this potting mix review, Purple Vienna Kohlrabi (a quick-growing microgreen) was grown as a test subject. It also was grown in Miracle-Gro and Home Microgreens potting mixes.

The comparison result of that test was a wash with both potting mixes doing a great job of growing the microgreens. You can read more about that test and see how we planted and set up both sets of trays in the following article.

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How Well Does Miracle-Gro Potting Mix Grow Basil?

The video below shows the results of the basil growing test between the two potting mixes. More information is provided below the video.

Miracle-Gro Potting Mix Growing Basil Microgreens Video

It shouldn’t be surprising that a potting mix that contains quick-acting synthetic fertilizer will grow microgreens very well. 

Miracle-Gro Potting Mix does a great job of growing basil and most likely any slow-growing microgreen.

But let’s dive deeper into the review to see if other factors affect my buying choice. 

Miracle-Gro Potting Mix Review

Here are my thoughts and recommendations for using Miracle-Gro Potting Mix for microgreens and other indoor garden plants.

This article will be focused on what ingredients are in the potting mix, how easy it is to use, and how well it performs when growing slow-growing microgreens like basil, cilantro, celery, or other microgreens that take more than 20 days to harvest.

Most Troublesome Point For Me

Before you go out and buy Miracle-Gro Potting Mix you should come to terms that it contains synthetic fertilizers.

I know this is a no-go for many people.

But there may come a time when you need a potting mix, and Miracle-Gro is a popular brand available almost anywhere. Don’t forget that a chemical in itself is not harmful; only the dosage of that chemical can harm you.

I always keep that in mind. However, I will not use Miracle-Gro Potting Mix to grow my microgreens unless it is all I have available mostly because I’d rather support smaller businesses than a company as large and influential as Scott’s. 

But if you choose to use their products I am not one to judge.

Is Miracle Gro Potting Soil Safe to Grow Microgreens and Vegetables?

According to Scott’s product website, Miracle-Gro Potting Mix is safe to grow vegetables and greens. I have no proof other than what they state on the website, nor could I find any agency or watchdog group that says otherwise.

Here is a statement on the Scott’s website (taken in 2023)

Reasons 1 & 2 for Using Miracle-Gro

This potting Mix is by far the most common potting mix found on the shelves of mass market retailers.

It can be found everywhere. Most of the larger stores carry 8-quart and 2-cubic-foot bags. Amazon does have a 1-cubic-foot bag that is a nice middle size.

The second reason is that it is inexpensive. Saving money is always good.

What Ingredients Are in Miracle Grow Potting Soil?

The potting mix ingredient list differs depending on what state (most likely country, too) it is sold in.

The short of it is that the ingredient list contains peat, sphagnum peat, forest products, maybe coco coir, perlite, synthetic fertilizers, and synthetic wetting agents.

I have an article that explains all of the ingredients in Miracle-Gro Potting Mix and also explains what wetting agents are and what chemicals are in them.

How Easy is it to Use Miracle Gro Potting Soil?

As a side note, Home Microgreens Potting Mix contains only natural amendments. There are no synthetic products; instead of a peat base, it is mostly coconut coir-based. I also have an article on what ingredients Home Microgreens Potting Mix contains.

I found that Miracle-Gro potting mix is easy to use. It is fine enough for easy spreading and leveling in the trays.

There is a bit of inconsistency in the size of the forest products, but not to a point where it is difficult to use.

I did find that Miracle-Gro Potting Mix didn’t absorb water as well as the Home Microgreens Potting Mix. You can see that in the video posted in the first article.

However, it wasn’t so slow that it inferred with sowing seeds like some mixes have in other trials. It makes me wonder if it will absorb or wick up water and a coir-based product when bottomed watered.

Overall, I found it easy to use Miracle-Gro Potting Soil when filling trays or sowing microgreens.

How Well Does Miracle Gro Potting Soil Grow Fast & Slow Growing Microgreens?

Both videos show that the potting mix grows microgreens very well.

As shown in the first article of this series, Miracle-Gro Potting Mix grew the Purple Vienna Kohlrabi like a champ.

Let’s concentrate on the slower-growing basil microgreens.

From the first growth six days after planting it does look like Miracle-Gro Potting Mix germinates basil microgreen seeds either quicker or once germinated, the plants grew faster than those in the HM Potting Mix.

I mentioned In the Kohlrabi grow article that the Miracle-Gro Potting Mix required more water than the Home Microgreens Mix. I did not find that so in the basil trial. Both trays needed watering at the same time and given equal volumes of water.

Throughout the grow, the basil microgreens in the Miracle-Gro Potting Mix are slightly taller, the leaves larger, and the color looks darker as you can see in the following sequence of photos.

In all of the photos, Home Microgreens Potting Mix is on the left, and Miracle-Gro Potting Mix is on the right.

Basil Microgreens Day 7 – One Day Under Light

Not much of a change, but I like to see how quickly microgreens green up once light hits them.

Basil Microgreens Day 9

The basil growing in the Miracle-Gro tray looks fuller and taller, and the leaves are a bit larger than those in the naturally amended potting mix. Remember, both trays had the same weight of seed from the same seed lot.

Basil Microgreens Day 15

The true leaves are well on their way to forming. You can see that the leaves growing in the Miracle-Gro Potting Mix (right tray) are larger and the plants taller.

Both trays look good, nice and green, very high percentage of germination, and steady growth for a slow-growing microgreen like basil.

You can see that the basil microgreens are almost ready to harvest and in a pinch, you could harvest these.

Although the Miracle-Gro tray on the right is a little larger and taller, the basil microgreens in the Home Microgreens Tray are more comparable to them.

Basil Microgreens Day 22 – Time to Harvest

Here is a side or end view of the microgreens elevated so the camera can see the height of the greens. The basil microgreens in the Home Microgreens Potting Mix are as tall as those grown in the Miracle-Gro.

Same day (22) but from an elevated position. The leaves in the Home Microgreens Potting Soil (left) are now as large as those grown in the Miracle-Gro potting mix even with the synthetic fertilizer.

The tray of basil microgreens grown in the Miracle-Gro Potting Mix does look like it has a larger diameter and although the photo doesn’t show it well, the green color is darker.

The Miracle-Gro Potting Mix has grown the basil microgreens a bit larger than those grown in the Home Microgreens Potting Mix. I would say that the natural amendments in the HM potting mix are starting to affect the growth in a positive way in the later stages of the trial.

Overall, in both quick-growing and slower-growing microgreens Miracle-Gro Potting Mix will grow microgreens very well.

This Isn’t a Surprise

Synthetic fertilizers grow plants quicker than those grown in soils with natural amendments.

Miracle-Gro Potting Mix contains soluble synthetic fertilizers, while the Home Microgreens potting soil has only natural amendments and should start slower but finish stronger as it takes longer for the natural amendments to become available for the plants to use.

While less apparent in the kohlrabi trial, the statement seems to hold in the basil grow as on day 22 the gap between the two trays is much smaller on day 6 or even day 16. 

My brain is racking with all kinds of different tests to try to figure out how each of these different methods of plant growth simulation occur so I can exploit them for the good of the home microgreen grower.

But in reality, the point of this and any other potting mix trial I run is to find the soils that produce good microgreens. And to explain what each potting mix contains and uses to produce excellent growth so you the reader can make a good buying decision.

This way the decision is based on your mindset toward, natural and synthetic ingredients, the environmental impacts production and transportation have on the world, and the social impacts and working conditions that harvesting and production of the ingredients have on the workers.

I guess my job if you will, is to report the facts and only the facts here in this section of the article. I’ll post my opinions in the recommendation section.  

via GIPHY

If you don’t know what this gif is from, well it is old. Even I only saw reruns of the show. True Fact, Joe Friday never said “Only the facts, Ma’am.” It was actually rephrased by Dan Aykroyd in the late 1980’s parody movie from Sgt. Joe Friday’s actual quote “All we want are the facts, ma’am.”

Do I Recommend Miracle-Gro Potting Mix for Growing Microgreens?

This is the second Miracle-Gro Potting Mix review article. In the first article, I grew Kohlrabi a quick-growing microgreen to see if the fertilizer in the potting mix grew microgreens quicker than a potting mix without a synthethic fertilizer. There wasn’t much of a difference, but it did grow the microgreens as well as other mixes.

In this article, we choose to grow a slow-growing microgreen in basil. The Miracle-Gro mix had a quick start and outperformed the known natural potting mix. However, late in the test, say after day 19, the growth rate seemed to slow down. But it still grew microgreens to a larger size than the naturally amended potting mix upto day 22 of the grow.

If you can warp your head around the synthetic fertilizer and wetting agents in your potting mix, then Miracle-Gro Potting Mix may be for you.

The potting mix grows microgreens very well.

Miracle-Gro potting mix is easy to find as almost every garden center, home improvement box store, and even independent merchants carry the product. It is inexpensive compared to other potting mixes, easy to work with, and grows colorful and full trays of microgreens.

It grew both fast-growing and slow-growing microgreens very well. Even slightly better than Home Microgreens Potting Mix, which has shown that even with all-natural amendments, a well-engineered natural potting mix can grow as well as well-known large brands.

As mentioned, I’m not a fan of buying short-term products that contain petrol-based ingredients. I’m still unsure about the health concerns of the ingredients in wetting agents. But I will say that this product does not contain a significant volume of wetting agents.

Besides the synthetic chemicals (I try not to use any in my food products), my principal reason for not supporting Miracle-Gro is Scott’s brand itself and the other products and clout they have in the marketplace.

I’m not fond of the conglomerate companies that buy up or take over brands. I’m not getting into all the reasons here; I’ll only state that I like to support small companies that are not part of larger entities.

Here is a quote from a press release about the Scott’s brand:

With more than $2 billion in worldwide sales and more than 6,000 associates, The Scotts Miracle-Gro Company, through its wholly-owned subsidiary, The Scotts Company, LLC, is the world’s largest marketer of branded consumer products for lawn and garden care, with products for professional horticulture as well.

The Company’s brands are the most recognized in the industry. In the U.S., the Company’s Scotts®, Miracle- Gro® and Ortho® brands are market-leading in their categories, as is the consumer Roundup® brand, which is marketed in North America and most of Europe exclusively by Scotts and owned by Monsanto.

The Company also owns Smith & Hawken, a leading brand of garden-inspired products that includes pottery, watering equipment, gardening tools, outdoor furniture, and live goods. In Europe, Scotts’ brands include Weedol®, Pathclear®, Evergreen®, Levington®, Miracle-Gro®, KB®, Fertiligene® and Substral®.

But I’m not here to judge anyone’s decision (nor should you), and if someone is comfortable with a product, what it contains, who it supports, and the other products it makes, then by all means, Miracle-Gro Potting Mix will grow outstanding microgreens for you.

A Little Love for Home Microgreens Potting Mix

For me, the biggest takeaway in this two-article trial is how well Home Microgreens Potting Mix held up to a well-proven brand that contains a fast-acting synthetic fertilizer.

I realize it is much more expensive, mainly because of the extra cost of me having to ship the potting mix out to you. Plus the number of times I need to handle the product before you get it (six times by my count). 

But it does grow nice microgreens and can be used to amend gardens, landscapes, or lawns after using it for growing microgreens. 

If You’d Like to Support a Small Family Business

Check out the Home Microgreens store.