12" wide grow boxes versus 18" wide grow boxes which are better and why?

What improvements were discovered when Dr.Mittleider switched from 12"
wide grow boxes to 18" wide grow boxes?

Syd_can & Group:

Dr. Mittleider never did tell me much about his reasons for changing his recommendations in this measurement. He continued to use 12"-wide Grow-Boxes in his own home garden until he moved from Salt Lake City, Utah back to Loma Linda, California at the end of 2002.

But in the garden Jacob and I built in the Assisted Living Center in Loma Linda, in which he and his wife lived for several years, the boxes were 18"-wide, and of course they worked great.

I believe that for crops exclusively grown in only one row per box that 12" is sufficient, but when you have 2 rows in a box the plants need the extra space, and so Jacob decided it was best to standardize on one size that would work for all plants.

The plant rows are about 14-15" apart in the boxes, but when growing in the soil, because of the space taken up by the ridges, the rows of plants are about 12" apart, so go figure.

And in the soil Jacob liked aisles of 3 1/2', but in a Grow-Box situation he often said 3' was adequate. I believe that difference is because of the space the ridges take up in a soil-bed garden.

In either situation proper pruning is the key to success. With good enough and often enough pruning even aisles as narrow as 2 1/2' can work, but I never recommend that, because most people will not prune enough and they'll end up LOSING productivity because their plants and fruit don't get sufficient light.

Jim Kennard