Today I had a few extra dollars.  So I went to Walmart to find the best deal on dirt.  Yes, dirt.  In Nevada, two of our most precious gardening commodities are water and dirt, two of the things I try to keep my kids and dogs from tracking into the house.  But if you attempt to garden here, without amending the soil in any way, you’re going to grow something that looks like this:

Nevada dirt

Our soil is very alkaline and extremely clay-heavy. To get a good humus, you actually need water plus green matter to decompose. In Reno we get a little bit of water in the winter, mostly in the form of snow, but the elements just aren’t right for any kind of soil that will grow a good, healthy garden. Good dirt is rare enough here that we plan to build a composter this summer. But my potatoes-in-a-bucket need dirt now.

Potting soil?  That would be great!  But we already have nine 5-gallon-buckets for potatoes.  We also plan to have at least 25 more global buckets containing tomatoes, squash, bell peppers, peas, cucumbers… Well, we just need more dirt. If we filled each of these buckets with potting soil, we would spend at least $80 on dirt.  At least.

So we made it.

In another 5-gallon bucket, I had my husband mix:
1 part storebought garden soil
1 part topsoil from my existing garden
1 part horse manure (from one of my clients’ corrals)
1 part storebought compost (which is more composted wood than anything. Few nutrients.)
2 cups storebought perlite, to help with drainage

Our resulting mix:

Good dirt

Isn’t it pretty? It looks like fudgy chocolate cake or Oreos, all crumbled up into a bowl. That’s a good thing.

The cheapest price we found on garden soil today was $2.75 for 2 cu. feet, which would fill one of our 5-gallon bucket planters if we didn’t stretch it out a little. We’ll probably find a cheaper price later in the season, but right now the selection was a little sparse. The perlite cost $6, but a small bag will be enough to help the drainage in all of our pots this year. The compost was about $4 more, for about 5 cu. feet.  So far, we have spent less than $20.

I have to take a second and mention that this storebought compost is not the “black gold” that you’re going to read about on organic gardening sites. To get the really good compost, you either need to make it ourself or get it from somebody local who has also made it. The garden store compost is mostly decomposed wood. This will really help with the drainage, but it won’t add the kind of nutrients that you would get from composting your kitchen waste.

If you live in my area and you’re going to make your own mix of dirt using existing topsoil, I recommend finding some that is already partially amended, or some that comes from an area close to the river.  Anything you find far from a riparian system is going to be mostly clay, which will bind together and won’t drain well. You can use a little, but don’t depend on it too much.  We learned this last year when a friend brought us a truckload of “good dirt,” finely sifted and free of rocks.  It was great for landscaping, but it was still mostly clay.  When we tried to water it, the water sat on top then ran off, leaving thirsty little plants.

Manure is basically plant matter that the animal has partially composted for you.  But be sure to only use cow (steer,) horse, chicken, sheep, or goat manure.  Don’t use anything that comes from omnivorous animals.  It’s easy to understand why when you realize that those animals eat the same foods that we’re supposed to cook before we eat.  I don’t want to have to worry about e. coli on my spinach or salmonella on my tomatoes. 

This same rule can apply for composting.  I only compost plant-based material, with the exception of eggshells.  Fats and meats don’t decompose as well, and can encourage the growth of the wrong kind of bacteria.  I realize that not everyone does this, and I don’t want to put down anyone else’s techniques, but I choose to feed my animal-based scraps to my dogs.

Next year, we won’t have to spend as much on dirt.  I can store this year’s dirt in a pile, throwing in some leaves, carrot peelings, or eggshells in the fall, and let it break down over the winter.  But by using the manure and the existing topsoil this year, we can stretch the dirt enough to fill all of our global buckets, grow some worthwile produce, and not have to buy a bag of potting soil per bucket.