Should I Add Garden Soil To My Garden

I want to add garden soil to improve my garden. Is this a good idea?

Many folks think they have to add garden soil to get a decent garden and I hear this all the time, “Let’s add some soil to make the garden better!”

The reality is quite different. Unless you are trying to grow in beach sand (I was in one garden) or raise the level of your garden, then your efforts are a waste of time and money.

What you want is better soil so you can grow better or bigger plants.

I brought two truckloads of “soil” in to make a raised bed as we have 2-inches of clay soil over shale rock so not enough to grow on. This is the only real reason imho to bring in soil. Having done this, I started the ongoing task of making this into decent topsoil.

Two truckloads of field soil (no manure added) to make my garden.
Two truckloads of field soil (no manure added) to make my garden. (Image the author)

You have two options to improve your soil

Option one:

You can dig up all your plants (you can’t bury plants under new topsoil)

You bring in a load of topsoil and spend the time spreading it around the garden. Hauling it here and there, raking it and getting it level. Then you reinstall the plants.

Your soil level is higher but not necessarily better.

I note that some topsoil companies add manure to their load to make the soil appear richer but this is simply buying expensive manure. It’s gone in a few years as the manure decomposes and you’re almost back where you started.

Option two

Or you can spend the same amount of money on bagged manure or compost. Or even bales of straw.

Spread that over your garden soil (without having to dig up plants or dig it in or rake it or ??) as evenly as you can and then walk away. The job is done. (If you can get a load of manure from a nearby farmer you’re even better off but nearby farmers are hard to come by in the suburbs or downtown cores.)

raised bed vegetable garden
The raised bed vegetable garden I made from the soil above

Bottom Line:

  • Bring in soil to raise the level of your soil.
  • Bring in compost, manure or organic matter to create better soil.

Biochar research on soil moisture and fertility

This biochar research is interesting.

Soil scientist Jeff Novak at the ARS Coastal Plains Soil, Water and Plant Research Center in Florence, S.C. is the lead researcher to evaluate the effects of biochar on soil moisture and fertility. There are multiple locations across the US involved in this.

Several different kinds of organic matter – ranging from switchgrass, hardwood, poultry manure were used to produce 9 different “kinds” of biochar (and here you thought it was just “one” product. 🙂

The difference were in the temperature differences the material was burned to produce the char.

And the biochar was tested on sandy soil and two kinds of silt loam soils at 20 tons per acre. (approximately 2/3 pound per square foot.

After 4 months, the soil was retested and the results showed biochar made from switchgrass and hardwoods increased the soil moisture storage in all three soils. The switchgrass biochar produced with the highest temperature gave a 3-6 percent increase over the others (it was the best) and increased the soil moisture holding ability of the soil by 3.6 days for soybeans (other crops were not reported – but all have different moisture needs so there’s a variation here)

Having said that, the higher temperature biochars increased soil pH. And poultry litter biochar increased the availability of phosphorus and sodium.

Bottom Line

The researchers clearly pointed out that one size does not fit all when it comes to biochar (naturally, there’s not going to be a silver bullet here.) :

And that we may be able to custom design and deliver benefits to individual crops in the future based on soil deficiencies.

For now – it probably isn’t going to hurt to mess about with this in your own garden (other than the rise in pH which troubles me a bit).

But all the bumpf on the Net about using biochar is likely hype or wishful thinking at this point.

Results from this study were published in Annals of Environmental Science and in the Journal of Environmental Quality.

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