Garden Myths - Learn the truth about gardening

Archive for the Soil Category

Sand and Clay Don’t Make Concrete

What happens when you add sand to clay soil? Many people claim that this will make concrete and others say that it results in soil that is easier to dig. How can there be such large discrepancies about something that is so easy to test?

Why is this a problem? Gardeners with heavy clay find it difficult to dig, so they want to loosen it up. Sand is very easy to dig and it makes a lot of common sense to add it, to create a looser soil.

Soil texture triangle - sand and clay soil

Soil texture triangle – sand and clay soil

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Mulch – How Does It Affect Soil?

Mulching the garden is a very common recommendation. Mulch will reduce the number of weeds and it will hold moisture in the soil but how does mulch affect the quality of soil?

There are lots of claims that mulch improves soil but have you ever seen numbers to validate them? I haven’t either. How exactly does mulch improve soil? It should add organic matter, but how much? It should increase the number of microbes, but is this really true? Unfortunately, almost nobody studies landscapes and gardens because no one will fund the work.

Luckily I was able to find one very good research paper that looked at this exact problem.

Effect of fertilizer and mulch on soil, by Garden Myths (based on reference 1)

Effect of fertilizer and mulch on soil, by Garden Myths (based on reference 1)

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Sterile Soil – Does it Really Exist?

There is lots of talk about using sterile soil. Some people even sterilize their soil before they use it. Others buy bags of sterile soil. All of this is done in an effort to reduce pests, diseases and sprouting seeds. This all seems to make a lot of sense but there are a couple of basic questions that one should ask;

  • Does sterile soil really exist?
  • Does sterile soil make a difference to your plants?

 

I’ll deal with the second question in my next post. Today I want to discuss the existence of sterile soil.

Sterile soil

Sterile soil – does it exist?

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Does Fertilizer Kill Soil Bacteria?

Read most organic books or blogs and they will tell you that synthetic chemical fertilizers are killing the bacteria and fungi, the microbes, in soil. Dr. Ingham and her Soil Food Web preach this same message. Stop using fertilizers because they kill the bacteria and fungi. My review of Teaming With Microbes found the same message repeated several times.

Does fertilizers really kill bacteria or fungi in soil?

Some people claim that the ‘salts’ in fertilizer do the damage, but anyone making such a claim does not understand what happens to salts in soil. I’ll explain this in more detail below.

 

Does Fertilizer Kill Soil Bacteria?

Does fertilizer kill bacteria?

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Teaming with Microbes – A Close Look, Part 2

Teaming with Microbes, A Gardeners Guide to the Soil Food Web was reviewed in an earlier post Teaming with Microbes – In-depth Book Review and in Teaming with Microbes – A Close Look, part 1.  In this post I’ll look at more content of the book and discuss their validity and the validity of the soil food web. A gardener can learn a lot by looking at these topics in some detail.

Teaming with Microbes - A Close Look, Part 1

Teaming with Microbes – A Close Look, Part 1

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