I’m a self-taught gardener. I don’t like unnecessarily complicated things. When any topic gets too scientific or complex, my eyes glaze over and I start to think about lunch. With our already hectic lives, some think we must know about the microcosms and ratios in our potting soil or garden soil in order to be a gardener, but – don’t tell anyone – I don’t. I haven’t. Because I don’t need to.
Now keep in mind, I’m a gardener. I’m not a grower. I don’t have a greenhouse. I don’t have any sort of grow-your-own set-up here at my backyard nursery. I have tried growing my own stock but it just isn’t where my passion is. I do grow my own veggies and annuals from seed for my full-sized gardening adventures, but that’s where it stops. However, if you are getting into growing seriously, you might want to focus on the content of your soil.
There’s an old saying that if you have $1 to spend on your garden, spend 90 cents on soil, and 10 cents on plants.
And I’ve written about soil before, it’s the first chapter in our popular Miniature Gardening 101 Series: The Dirt on the Soil. And, I talk about it in here, How to Plant a Miniature Garden in a Big Pot.
But what about all the different kinds of potting soil out there? What’s the diff? What do we use for miniature gardening? What will work best? Oh, and how much? Grab a cuppa, and let’s get down to the roots of the situation, shall we?
For Pots and Containers
For all containers, use organic potting soil. Note that a lot of companies have hooked their wagons to the “organic” trend and, well, soil IS already organic, so isn’t that redundant? Not in this day and age, unfortunately. By organic, I mean without any added fertilizers or water-retaining polymers.
A great example is Miracle-Gro soil. It’s everywhere now and everyone sells it only because they have the money for marketing it. (It’s made by Scott’s. Monsanto owns Scott’s. Icky.) You’ll find somewhere on that bag of soil it will say ‘organic.’ But those added fertilizers and water-retaining polymers is the WORST soil you can use for your miniature garden or fairy garden simply because of the extra “stuff” in the soil. The extra fertilizers burn the roots of our plants and trees and those polymers don’t let the soil dry out often enough, then the roots can’t breathe – with that lovely combo, our plants that we recommend for the miniature gardening die.
What I love to see on the potting soil bag is that it’s from a local company. If the garden center that you frequent are worth their salt, they’ll have a variety of soil products from companies in your area or thereabouts. If you don’t see it on the store shelf, ask for it. The request will get back to the manager/buyer and they’ll know customers are looking for a local choice.
How Much Soil Do I Need for My Miniature Garden Container?
Because some of our plants are really tiny, it is miniature gardening after all; you might be tempted to put the tiny plants in a big pot to let them grow in. This is called “swimming in soil” and the reason this will not work is that the water will not stay around the root ball where it is needed because there is too much soil in the pot. The water wicks to the bottom of the container, away from the plant’s roots and all is futile. A basic rule of thumb is any new plants need to transplant in pots that are 2” to 5” bigger or wider. If you’re planting a group of plants, take the total of all the pots combined.
This chart was taken from my Gardening in Miniature book that has all the garden basics you need to get started in the miniature garden hobby.
Doing the Math
Note that 1 cubic foot bag of soil or compost is about the size of regular pillow. There are about 25 quarts in 1 cubic foot. So, using the chart above, a pot that is 8 to 11 inches wide, will take almost half a bag, or half a cubic foot, to fill it up. Note that the depth of the container isn’t accounted for in this chart but, it should say “width and depth” of pot. But here’s an awesome soil calculator – updated: google “soil calculator” for the latest!
For In-ground Miniature Gardens
Use compost. That’s it. Soil is compost but will have many more nutrients in it than bagged topsoil. Just spread the compost on top of your soil each spring, and you are done!
If you are just starting an in-ground garden bed of any type, try our type of lasagna gardening. Lasagna gardening is really ‘composting in place’ but that means that you have to pay attention to the ratios, layers, timing and materials… (Oh gee, what’s for lunch?? :o)
BUT what Steve and I did with our new garden beds when we moved to our house in 2010 was incredibly easy and worked like a charm. We laid a long piece of rope down to outline the edges of the new garden bed. We covered the grass with heavy cardboard, piled as much compost on top as we could on top, cut in the edge of the garden bed and installed the border. Then planted the garden in the compost. Done.
We top it up each spring as much as we can. Now the garden bed has settled down to ground level but it works better for the miniature garden scene than a mound – the paths and patios stay level and the watering doesn’t mess everything up.
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