If you compulsively search online for inexpensive microcontroller add-ons, you will see soil moisture measurement kits. [aka] built a greenhouse with a host of hacked hardware including lights and automatic watering. What caught our attention among all these was Step 5 in their instructions where [aka] explains why the cheap soil sensing probes aren’t worth their weight in potting soil. Even worse, they may leave vacationers with a mistaken sense of security over their unattended plants.

The sensing stakes, which come with a small amplifier, work splendidly out of the box, but if you recall, passing current through electrodes via moisture is the recipe for electrolysis and that has a pretty profound effect on metal. [Aka] shows us the effects of electrolysis on these probes and mentions that damaged probes will cease to give useful information which could lead to overworked pumps and flooded helpless plants.

There is an easy solution. Graphite probes are inexpensive to make yourself. Simply harvest them from pencils or buy woodless pencils from the art store. Add some wires and hold them with shrink tube, and you have probes which won’t fail you or your plants.

Here’s some garden automation if this only whet your whistle, and here’s a robotic friend who takes care of the weeds for you.

If you’ve ever walked around West Oakland, farming probably doesn’t come to mind. That’s because it’s the fifth busiest shipping port in the United States. But that hasn’t stopped maker Eric Maundu from feeding himself with locally-grown food from his aquaponic gardens, a combination of fish farming and hydroponic planting. Frequently proclaiming, “I am not a farmer,” Eric has applied his robotics and software background to making gardens smart.

“I feel knowledge of electronics and software programming makes me a better farmer than just having a hoe. Gardens that can communicate for themselves using the internet can lead to exchanging of ideas in ways that were not possible before. I can test, for instance, whether the same tomato grows better in Oakland or the Sahara Desert given the same conditions. Then I can share the same information with farmers in Iceland and China.”

His company, Kijani Grows, sells kits, components, installs gardens throughout the Bay Area, and teaches classes on aquaponics. This inspiring video from fair companies gives an epic walkthrough (note the length of the video – how leet!) of his various indoor & outdoor systems and designs: