NGA study

The MSM recently reported on the results of a National Gardening Association study that indicates many more people are planning a vegetable garden this year. I was suspicious about claims in the report that on average a $70 gardening investment can yield $600 in vegetables. After reviewing the full results of the study, I remain skeptical (the study can be found here: NGA study).

There are many factors that can affect investments and yields which are not discussed in the report. For instance, there is a significant difference in the cost of maintaining an existing garden versus starting a new one. Also, it is not at all clear that the people with 600 square foot gardens (from which the $600 ROI figure comes) are the same people who invest $70 in gardening. Note that the median size garden in this study is 96 square feet. This means that there are some really large "gardens" out there skewing the average. I would have to plant (38) 4' x 4' frames to match the average size garden in the study and it would definitely cost me more than $70 to get that going.

The "square foot gardening" (SFG) method that I am using is relatively expensive to get started, however good results are almost guaranteed and expenses in subsequent years are minimal. "Square Foot Gardening" is a term coined by Mel Bartholomew who wrote the original book by the same name in 1981. Some advantages of intensive gardening methods like SFG are that soil amendments can be concentrated in a smaller area and that watering systems, protective barriers and season extenders can be more compact and therefore less expensive.

In spite of problems with the NGA study, I find the expected return on investment per square foot of garden an interesting starting point. It boils down to about a $1 return for every square foot of land that is cultivated. This is assuming on average 1/2 pound of produce per square foot and an average cost for vegetables of $2 per pound at the grocery store. I am planning to see how close that matches my results is this year.

It would be interesting to compare different styles of gardening (intensive versus traditional rows), how much investment is required in each and how much return can be expected. Investments might include soil improvement, watering systems, protective barriers, season extenders (cold-frame/row covers), and tools. Also, the cost of startup can be compared with long-term maintenance costs. The amount of time required to maintain various configurations might also be considered.

I scanned an intriguing new book this Winter (Gardening When It Counts: Growing Food in Hard Times by Steve Solomon) that argues that the square foot and other intensive gardening methods are less productive and more resource intensive than traditional gardening methods. However, I have not had a chance to study the book in depth. For now I remain convinced that the square foot method offers the best return for my time.