Ab EarthBox "Collar?"

[greatgardens]

For several years, I've wanted to try a slight modification on one or two of my EarthBoxes. It would be the addition of a collar around the top of the EB to make it slightly deeper -- say about 3".  The first question that I always get is "why?"  The answer is an increase in the area for roots, and in particular for a drier area since there should be less wicking as we get higher from the reservoir.  Also, some plants in the EB do not seem to like the constant wet feet, and within reason, the amount of perlite added to the planting mix seems to make little difference. Another possible reason is that with two plant per box, some varieties do not grow as large as they do in garden soil. Eggplant is one that seems to produce more under-sized fruits vs the garden. So good or bad, those are my reasons. It may fail as an experiment, but I want to try it.

Now the real question -- what to use as a material to make the collar?  It should be easily available, non-toxic, and will still co-exist with the cover and fill tube. (I have an extension for the tube, so that is not an issue.)  Things I've toyed with -- cedar planking (but it is pretty thick which creates some issues with the fill tube).  Landscape edging -- but I have concerns about what that stuff is made from.  I could sacrifice an old EB, but I do hate to destroy a perfectly good box. So... do you have a suggestion for the collar material? Thanks.

[feetz]

You are absolutely correct.  Adding an extension will provide an area that "gets water at a slower rate".  With approved potting mixes or straight peat moss, you can easily get strong wicking to 18" and beyond. You could flip an older or cracked Earthbox and ziptie it at the rim then cut holes for planting sites. You could also use plastic from barrels or plexiglass or line wood with plastic sheeting. Another option is to experiment with using barrels or large plastic pots instead of modifying perfectly good Earthboxes. More options are to not fill one of the wicking areas in the bottom of the earthbox when adding potting mix OR shrink the amount of wickable area in each of the wicking pockets which will restrict the flow of water on the hottest days but may not affect the mix saturation on cloudy, cool days.

I mention "gets water at a slower rate" because on cloudy or cooler days or if the box is inside under lights, the plants will not transpire as much and the upper layers of potting mix will be much wetter than on warm, sunny days. Taller potting mix will also reduce germination of seeds at a certain point.  I found a 12" potting mix height to be a good compromise between cost and flexibility. Heavy feeding plants like tomatoes or corn may not perform as well if roots cannot access enough water due to drier root zones (wilting).  Hope this helps.

[greatgardens]

Thanks!  It gives me some added thoughts that are "outside the box." I'll think some more about stuff I have laying around that might be useful -- like adding a partial grow bag on top of the EB. I had only thought of rigid materials, but no reason that it couldn't be heavy fabric or such.  I do want to retain the reservoir since that makes watering a lot easier.  (And my summer toads like the filler tubes and reservoir, also!)

-GG