Square Foot Gardening - no dirt allowed!

Square Foot Gardening (SFG)doesn't use dirt for growing. That's right...no dirt. It's a soiless mix of 1/3 peat moss, 1/3 vermiculite and 1/3 compost. 

Here's the link again to the "official" square foot gardening website. It's a great site full of information on how to go about it.

Square Foot Gardening

Over the last few years while living in New Mexico, I had a very small SFG.  I had carefully blended a beautiful mix of home made compost and a variety of animal poop. I had chicken, horse, goat, cow and llama poop...it was a potpourri of pooh! If you're a gardener, you will understand when I say it was beautiful!

When we got the word that we were moving, I was not leaving that beautiful mix behind. I braved the jokes and eye-rolling from my husband G.W. and loaded it all up in some clean trash cans and tubs, then drove it 400 miles north to our new home. Yes, I moved "dirt" and I am proud of it!

Here is my "dirt"

 

Laugh if you want to!

 

 

OK...back to the topic at hand...creating the soiless mix:

Peat moss and compost are easy to find at any big box store.  If you can, start your own compost pile, since that's the hands-down best quality compost.  Store-bought compost, like store-bought anything, isn't nearly as good as homemade. It's not pure compost. It's mixed with peat moss to stretch it out. 

Because peat moss is another component of the soiless mix, you have to make some adjustments in the quantity of peat moss if you are using store-bought compost.  I'll detail that in the next garden post.

In order to get a good balance of nutrients from store-bought compost, buy five or six different kinds.

Here's my six kinds of compost and the big bales of peat moss. It's only a small portion of what I'll eventually need to fill all of the raised beds, though.

 

The vermiculite will be the hardest ingredient to find. Most garden centers sell it in small 8-quart bags. A 4' x 10' raised bed like mine requires 13 cubic feet of each ingredient, so those tiny little garden center bags just weren't going to cut it. I had to get creative to find vermiculite in huge quantities.

 

A quick Google search showed me that vermiculite is also used as insulation around fireplaces and in attics. The same search also taught me that since the early 1990's, vermiculite is certified asbestos free. If you've heard any scary stories about asbestos in vermiculte, rest assured that is no longer the case.

 

If you're wondering what the heck vermiculite is, you aren't alone. It's a volcanic mineral. It's extremely light and can hold/retain water. Those qualities make it ideal for gardening!

 

Here's a link to a site with some information about vermiculite:

Vermiculite.com

So..... meanwhile, back at the ranch, I got the idea to check with the Lowe's and Home Depot insulation departments about BIG bags of vermiculite. Home Depot could order it for me...but it was going to cost over $50 for a 3-cubic-foot bag. I ran the numbers (I'm an accountant by trade, so 'running the numbers' is as natural as breathing for me!) and was sickened to discover that it would cost about $250 to get enough vermiculite to fill just one of the 4' x 10' beds. I have two of those size beds, plus two 2' x 10' beds and nine 3' x 3' beds! I'd have to resort to selling my blood plasma to fund the purchase of that much!

Luckily, I found a one-time source for vermiculite on Craigs List. A contractor had a lot of extra bags of vermiculite left over from a fireplace installation. He sold me 3-cubic-foot bags for just $18/each. That's a huge savings over what Home Depot wanted!

 

Here's my vermiculite:



 

 

That stuff's light as air. A 3 cubic foot bag only weighs fifteen pounds.  I'll end up needing some more of it, but this is a darned good start!  I'll just keep an eye out on Craigs List and maybe I'll get lucky again!

 

All that's left is to dump everything into the beds, mix it up and get planting!