Last week I talked about the importance of oxygen and how it gets to the roots; it must penetrate the air spaces in the soil and move into the roots passively, or without help of any kind. When planting in a container, special consideration needs to be given to the soil or potting media used to provide sufficient pore space for the roots to have oxygen

So, why can't you just take some beautiful top soil and put it in a planter? That's because the instant soil is moved, its physical properties alter, in this case, the capillaries are significantly shortened. Capillary attraction is the ability of a liquid to move up and into a small space, in other words, "defying gravity". This is important for roots in soil to have water in better supply after a rain, but can be problematic if too much water is held. A high quality farmland soil can have capillaries over ten feet deep!

Because most containers are often very shallow, it's impossible to have long capillaries. To overcome this problem, potting mixes are very coarse, allowing for better drainage (decreased capillary action). This makes them unable to overcome the force of gravity, allowing water to flow out and allowing oxygen to move into the soil and roots. The larger diameter capillaries of a potting mix are such that water is easily pulled down by gravity, leaving moisture only in the individual organic matter pieces, and plenty of room for oxygen.

 Thanks Mark!

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Happy Summer!!!

 As always, we appreciate your business!

Chuck and Darryl Newman
Planters' Choice Nursery