What Makes Great Garden Soil?

Organic Raised Bed Gardening on Facebook

Creating a garden soil mix is like making bread, everyone has a slightly different recipe. Below is a list of ingredients, and then I’ll talk about a mix.

My philosophy, and the philosophy of the site is to construct a raised bed and fill it with a garden soil mix.

Ingredients

Soil- if you have decent topsoil already, use it. Where I live, the soil is so full of rocks, that I never use it in my soil mix. Cheap potting soil or topsoil from the garden center is completely acceptable, although you don’t know if it contains chemical fertilizers or how it was processed. Organic potting soil is available.

Peat moss- adds a great soft texture and provides excellent moisture-holding capacity. The debate over peat moss is how long it takes to renew, and the distances it must travel to get to you. Add more compost if you want to skip the peat moss.

Or there are alternatives. Coir is coconut fiber and expands in water. You can use a nice, fine mulch, whatever kind is available in your area. Sawdust is also great for holding moisture. Even shredded newspaper will work.

Vermiculite or perlite- same as the peat, adds moisture-holding capacity. The downside is the price.

Mulch- is shredded up plant matter such as pine bark or leaves. Mulch helps hold moisture and slowly rots, releasing nutrients. Add in addition to or instead of peat.

Manure- any livestock manure is great stuff. It adds nutrients as well as active bacteria to your organic soil mix.

Compost – is broken down organic matter. It adds nutrients, holds moisture, and gives great texture and workability to your soil mix. Compost is alive and full of microorganisms.

Garden Soil recipe

My personal garden soil mix roughly follows the square foot garden method. I mix roughly 1/3 coir, 1/3 compost and/or manure, 1/3 mulch, and a small bag of vermiculite.

If you are going to use some sort of soil, mix 1/3 soil, 1/3 peat or coir, and 1/3 compost or manure.

Peat moss (or substitute) and manure or compost are absolutely required. Mulch is an extra, don’t use in large quantities if it’s very coarse. Mulch is also great on top of the soil. Vermiculite is expensive, so skip it if you have to.

Soil making tip

Save soil from potted plants you buy, the soil mix is usually very good and contains vermiculite or perlite. Is it organic? Who knows, but chances are it’s not going to hurt anything.

Here’s a movie that will show the soil mix in 30 seconds:

Charcoal, Carbon Sequestration, and The Mystery of Terra Preta

The ancient Amazonian people created an entire civilization on a super organic soil called Terra Preta. Charcoal has been found to comprise up to 40% of the super soil.

Preliminary tests have shown that charcoal, or biochar, along with ample compost, increase crop yields. I have dedicated a page to charcoal in garden soil.

Ways to Conserve Soil

In case you’re not fully convinced that organic gardening can benefit yourself and the planet as a whole, let’s look at soil conservation.

According to buzzle.com , 10 ways to conserve soil are:

• plant trees
• terracing
• no till farming
• contour plowing
• crop rotation
• soil pH
• water soil
• salinity management
• soil organisms
• indigenous crops

Let’s have a look at each point:

• plant trees and terracing

- okay, these don’t have much to do with organic gardening with a raised bed.

• no till farming

- We get a plus here. We make our own soil mix which requires no tilling, ever. All you need is a small, garden spade.

• contour plowing

- Another plus. Organic gardening with a raised bed requires no tilling and no plowing.

• crop rotation

- crop rotation is part of best practices, and I am supposing that most organic gardeners practice it.

• soil pH

- Another plus. Compost is pH neutral, and adding it in to soil will help neutralize the pH. Compost is the number 1 friend of the organic gardener.

• water soil

- You could argue for or against on this one. But I doubt many organic gardeners loose large amounts of soil due to wind erosion.

• salinity management

- Another plus. Saline soils result from crops that are heavily irrigated, such as cotton grown in the desert. It’s highly unlikely that organic gardeners are employing crops that need excessive irrigation.

• soil organisms

- Plus again. The treatment of soil in organic gardening encourages growth of soil organisms. We know that these unseen organisms are our best friends.

• indigenous crops

- Another one that could be argued either way, however, most organic gardeners lean toward heirloom seed and native varieties which have proven performance.

Related topics:

Organic fertilizer

Let worms fertilize your garden