I've finished expanding the five expandable RootBuilder 2 enclosures I have holding the five avocado trees along the side of my house. One warning for anyone (including future me) trying this is to take care not to allow mulch, dirt, debris, detritus or otherwise to build up around the bottom rows of the perforated "container." What can happen, as was the case with my trees is the roots will find themselves an escape route out the bottom rungs of the enclosure where ever they don't meet atmosphere at the exit holes. This presents a serious issue when trying to expand the container, especially for root sensitive plants like an Avocado.
My solution was to cut out the container losing the bottom two rows of holes (or ~2-3"). This shortened the height of my expanded container but allowed me to expand without further damaging the roots. The roots were spreading out the lower row(s) of holes and developing under my wood-chip mulching, where I assume the excess water was leaking and spreading out over the weed barrier I had laid down beneath the mulch.
I'm sure my avocado roots took something of a beating from all the stepping on the mulch and extraction process, so I've certainly dropped a good 75% of my fruit. But I'm sure the long term outlook is improved with these plants with the 3 additional panels of RootMaker.
I'd love to hear from anyone else using the containers on how they've managed with them, results and outcomes.
Thanks!
Here are some pics of one of the containers during the expansion process: