This Ficus benjamina (a bonsai in training) in a recycled soda bottle sub-irrigation planter (SIP) surprised even me with all my years of growing plants.
I'm in the process of reinstalling plants in the CuGreen lab to increase the plant care interval beyond weekly care. I need to do this pending upcoming knee surgeries and months of rehabilitation.
The tree was moved up from a 2-liter to a 3-liter soda bottle SIP on December 26, 2011. There were, of course, no visible roots after the replanting. When watering it this week, I was amazed to see the root system "explosion" in just 3 weeks. This is awesome!
As an aside, all school kids should be able to see the amazing “hidden world” of plant roots that I see every day because the SIPs have clear walls and the roots grow so well.
The most important factor about what we see here is the vivid demonstration of how plants thrive in SIPs. Know that sub-irrigation is scalable from windowsill herb growing SIPs to 4' x 8' raised bed SIPs. SIP “plumbing” fits all sizes of watertight planters. The key element is the water and oxygen reservoir that is an inherent part of all SIPs regardless of size or shape.
The benefit to the plants is that they receive an online supply of water, oxygen and nutrients. All we need to do is add an adequate amount of light.
In addition, the systems are hygienic when growing edible plants. There is no exposure to often-contaminated city soil. Why risk the possibility of a serious health problem when such a productive way of growing plants is readily available. All it takes is a little bit of knowledge. The systems are so simple to make.

I am captivated by this concept. Would you consider doing a DIY how to video? I saw the step by step photos on flickr but in one photo I saw a bottlecap and in others I did not. Then would like to know if you water it from the top first to keep it moist? How long until the plant can get water from below exclusively? Thanks!
Posted by: Dorothy Buechel | January 28, 2012 at 02:54 PM
Sorry for the slow reply Dorothy. You must be looking at my to-do list. YouTube videos are definitely on it. I just need to get past my medical issues.
I no longer use bottle caps with holes. They clog up with roots before too long. A cloth (poly batting or felt) retainer wick works much better. Plant roots will grow right through the fabric.
I might water from the top at time of installation to settle the soil into the planter. Other than that I never top water. Given adequate light the root system will make a beeline and find the water in the reservoir. Healthy roots are incredibly aggressive in finding water.
Keep in mind that you should wait until the water in the reservoir is consumed before adding more water. Also, the soil surface should always be dry. If it's moist you're adding too much water.
Posted by: Greenscaper | February 04, 2012 at 07:23 AM