Gardening Myths Debunked

Just finished reading a great little paperback (about 200 pages) debunking a number of common gardening myths.  The Informed Gardener, by Linda Chalker-Scott. Heard of it? 



I found it to be a quick, rewarding read written in an easy style that average folks like me can understand.  I'm a bedtime reader, so loved the fact that each chapter was just enough pages to make for a quick read before turning out the light.  There are 6 sections to the book, each focusing on a different topic:

  1. Critical thinking
  2. Understanding how plants work
  3. How/what/when/where to plant
  4. Soil additives
  5. Mulches
  6. Miracles in a bag/bottle/box

Inside each section are a series of myths.  Each myth is discussed, then the scientific reality is handed out, followed by a bottom line summation and a list of references.  4-6 pages tops on each subject with easy to understand explanations for the scientific stuff. 

I'm a big container gardening fan and was particularly attracted to the chapter titled "The Myth of Drainage Material in Containers". 
The myth is that adding a layer of coarse material (gravel, pebbles, pot shards and the like) to the bottom of a container will improve drainage.  I've been doing that for decades..... never questioned the practice.
The scientific reality is that water doesn't transition well between layers of finely textured materials to coarse ones.  Studies have shown that MORE moisture is retained in soil when a coarse bottom layer is present and the more coarse the material the harder it is for water to move across the interface.  Gravitational water will not move across that interface until the finer textured layer is totally saturated - meaning the soil will stay waterlogged.  Not a good thing when we're needing well drained soil to keep our plants happy.
So the bottom line is to use the same planting material throughout the entire container to ensure proper water and air movement.  I probably learned all about this principle in school way back when, but just never put two and two together.  Now I just put a used dryer sheet in the bottom before filling the entire thing with potting soil.   The soil can't work it's way out of the holes and everything can drain readily.

Linda had a lot to say about those hydrogel sprinkles we add to potting soil to increase water retention.  Suffice to say.... they're not so nice to the environment (or us either).  In their solid, dry state (polymerized form) they're harmless, yes, but over time (just a few years), they break down (depolymerize) and become toxic (acrylamide's nasty stuff)...... interesting how the manufacturer fails to tell us that part.  Now I know better......

So, The Informed Gardener, by Linda Chalker-Scott.   If you decide to go check it out, let me know.  I'd be interested in hearing which topics grabbed your attention and why.