I've been working with STG (Sure To Grow) media lately, and I have a few new thoughts to relay on the subject.  For those of you not yet familiar with Sure To Grow, here is a brief introduction:

Sure To Grow is a growing medium for hydroponics that somewhat resembles a cross between cotton and fiberglass insulation.  It comes in a variety of shapes and sizes, but all of them are fundamentally the same material.  It is somewhat unique in construction.  Although it is dense enough to retain water, it still has a large amount of air-space in the medium.  It's interesting stuff.

A few weeks ago, I started some seeds in the small (roughly one inch) cubes.  They work similarly to rockwool.  In fact, I'd suspect that rockwool is the biggest competitor for Sure To Grow.  Just recently, we've transferred the small cubes into larger cubes.  Sure To Grow offers a unique "stepping" size.  Take a look below for an example.  The small cube in the center is where each plant was started initially.  These days, the roots are speading into the larger blocks.

The larger blocks behave a bit differently than their smaller counterparts.  The larger cubes manage to retain water in their lower half, but the top remains dry.  For reference, my samples are sitting in an ebb & flow system with a one inch flood.  I like that the top stays dry.  This should cut down on any algae growth.

The larger cubes have a "hole" in the center.  This makes it very easy to move a small cube into a larger home.  Although it's not as obvious as I would like, you can see the small cubes in the center.  The new generation Sure To Grow has a denser construction, and is much improved from the first version.

In other news...

I've recently finished a minor modification to the DIY aeroponic system. This isn't a replacement as much as a new variant.  The sprayer system is simpler to construct than the previous version; and the overall cost should be roughly equal.  This one is intended to grow four relatively small plants in a compact unit.  

You may notice that the color of the unit is "whiter" that in many previous pictures.  There's a very good reason for this look... I've done some painting.  In an attempt to keep out more light (and in turn prevent algae growth), the exterior of the reservoir (and lid) has been sprayed with a plastic-bonding paint.  I'm pretty happy with the results.

We used some Krylon Fusion paint that we purchased at Home Depot.  It lives up to it's name.  We're very pleased with the way it bonded to the plastic of the Sortera container.

Upcoming Event:  The Maximum Yield expo will be in San Francisco on July 26th and 27th.  It's a very educational and useful show, if you happen to be in the area.  We'll be sending a correspondent, and details will follow after the expo.