You are correct that the GS box has a larger water capacity (4 vs 3 gallons) and the wicking design is...different. I wouldn't call it superior even though it looks like it would be. In practice both designs keep the entirety of the potting mix moist.

I use both and have a definite preference.

I prefer the earthbox.

I like the GS boxes though and I prefer those for water hungry plants like tomatos, cukes and pumpkins as that is where the extra 1 gallon reservoir capacity is really nice.

However there are 2 things I really do not like about the GS boxes.

The first thing I do not like is the fill tube. It has a water level indicator which I thought would be nice, but it's actually kind of a pain. Of my 4 GS boxes, the indicator broke on one. The way it is designed there is an end cap on it and they don't always fit snugly. In my case that end cap came off after planting and that makes the water level indicator not function. If you get the GS box I strongly recommend pulling the end cap off and putting a bead of waterproof glue on it.

Even with the water level indicator functioning you have to look right into the top of it to see the water level and this is easier said than done with boxes planted with large, bushy plants. The placing of the fill tube is also not convenient as it is on one side, in the middle. The EB tube is in the corner making it easier to get to.

The second thing I dislike about the GS design is how the overflow works. Out of the box, it doesn't work - at all.

If you do not read the instructions before setting it up and filling you are out of luck. The instructions indicate that there are 4 conical supports on the bottom of the box that the aeration screen rests on. To make overflow holes requires taking a pliers to the tops of those supports and ripping the tips of them off.

This results in the overflow going directly under the box whereas the overflow on the EB is right in front and a few inches off the ground.

May not seem like a big deal, but with my GS box with broken water level indicator I have no way of knowing if it's overfilled (or underfilled) because it is sitting on my lawn so I don't see any overflow. With the EB I never have to question water levels. I just stick the hose into the fill tube and run it until some water comes out the overflow and then move to the next one.

For balcony dwellers who are concerned about water overflow dripping down to their downstairs neighbor's balcony the EB design allows a rubber tube to be inserted into the overflow to redirect overflow, the GS design makes this almost impossible.

While I said I had 2 things I disliked about the GS design I just remembered a 3rd. The shape of the EB is more practical for most plantings than the GS box. The EB is long and narrow, the GS box is not as long, but wider.

The overall surface area is comparable. Your mileage may vary on this point, but I find the GS box shape to make it difficult to grow a lot of smaller plants like peppers. With an EB you can make two rows of whatever number, but with the GS box it's not quite wide enough to fit 3 rows. Kind of hard for me to describe, it's just easier to space plants in the EB.

On the positive side, the GS box is made of quality material, will last for years and is my choice when it comes to water hungry plants. For plants that don't use as much water I prefer the EB.

If I add to my collection it will almost certainly be EBs now that they offer an automatic watering kit that keeps the box always topped off with water with no oveflowing. Nicely resolves the water capacity issue (at a price ;-).

Interesting info on the GS SW planters. I have a few that are several years old. They must have changed their design recently. Mine didn't have an aeration screen in the bottom, so I just drilled holes in it myself. And I've built a few homemade ones, based on the designs posted here (search "homemade EB").

My only 2 cents would be that having an automatic self watering system would tip the decision to EB. After reading they were available just now, I ordered one. Just want to open it up and see what is unique about their valve.

My only 2 cents would be that having an automatic self watering system would tip the decision to EB. After reading they were available just now, I ordered one. Just want to open it up and see what is unique about their valve.

they have a valve now? interesting.

personally, i still like the homemade containers. you have more options when you do it yourself.

Thanks for you input justaguy. I am inclined to agree with you on all points.

But you say:
"In practice both designs keep the entirety of the potting mix moist."

This is the area that I am still curious about. The GS has a number of wicking channels distributed along the bottom, while the Earthbox has just two wicking chambers in the corners. Do they both work equally well? Is there no perceived difference in performance?

Nlight

The wicking works equally well in both boxes, at least as far as I can tell. I am using my earthboxes without covers this year and was concerned it wouldn't keep the mix as moist without the cover, but it keeps up with the GS box just fine.

I am using 2 parts pine bark fines, 1 part turface and 1 part peat in all of them. If you used a majority peat mix (ie store bought bag) it would be even more moist.

The GS boxes are on sale right now for $30 apiece. I just ordered two.

Sojourner

I agree on just about all of Justaguy's points, including preferring the GS boxes for tomatoes.

I was wondering if the GS container-overflow could be modified, because I too don't really like that the water drips out the bottom unseen until I hear it hitting my poor neighbor's deck. Instead of pulling the plugs on the peaks under the aeration screen, you could drill a substantial hole or two on the side at the same level, and even put in some tubing a la the earthbox.

Any reason this wouldn't work?