We just finished the last harvest for our potato plant study. We are comparing the growth, labor, and yield of five different potato-growing ideas: trench and hill, straw mulch, newspaper-and-straw mulch, containers, and towers. In order to help others reproduce our study or grow potatoes using these techniques, we are providing detailed instructions on our plant-out methods. See the archive of our research notes here.
Basic Summary Potato Data
To make the data in our study comparable for others who wish to repeat the test, we have to standardize everything. To that end, all the inputs reported here are given per square foot and per plant. First come the costs of running these different methods. Any growers looking to try out some of these methods need to budget, and data presented here will give a cost that can be multiplied out for his/her operation. Our planting density was 18 plants in 64 ft² (six plants spaced at about 16 in apart in three rows 32 in apart).
| Uniform Inputs | Trench and Hill | Straw Mulch | Newspaper-and-Straw Mulch | Container | Towers | |
| Seed | per ft² | $0.06 | $0.06 | $0.06 | $0.06 | $0.06 |
| per seed/plant | $0.23 | $0.23 | $0.23 | $0.23 | $0.23 | |
| Compost | per ft² | $0.43 | $0.43 | $0.43 | $0.43 | $0.43 |
| per seed/plant | $1.51 | $1.51 | $1.51 | $1.51 | $1.51 | |
| Mulch | per ft² | $0.13 | $0.13 | $0.13 | $0.13 | $0.19 |
| per seed/plant | $0.44 | $0.44 | $0.44 | $0.44 | $0.66 | |
| Container, if any | per ft² | $0.00 | $0.00 | $0.00 | $0.65* | $2.59 |
| per seed/plant | $0.00 | $0.00 | $0.00 | $1.00 | $9.21† | |
| Total | per ft² | $0.62 | $0.62 | $0.62 | $0.62 | $3.27 |
| per seed/plant | $2.18 | $2.18 | $2.18 | $2.18 | $2.40 | |
| *spent grain bags provided for free from Wisconsin Brewing Company | † 3.6 seeds per tower, each tower cost $33.17 |
To estimate the amount of each input needed for these growing methods, the following chart has measurements of inputs in square feet and per plant.
| Uniform Inputs | Trench and Hill | Straw Mulch | Newspaper-and-Straw Mulch | Container | Towers | |
| Seed | lb/ft² | 0.05 lb | 0.05 lb | 0.05 lb | 0.05 lb | 0.05 lb |
| ft² for each 3-oz seed potato | 3.6 ft² | 3.6 ft² | 3.6 ft² | 3.6 ft² | 3.6 ft² | |
| Compost | lb/ft² | 1.125 lb | 1.125 lb | 1.125 lb | 1.125 lb | 1.125 lb |
| lb per seed potato | 4.0 lb | 4.0 lb | 4.0 lb | 4.0 lb | 4.0 lb | |
| Mulch | % of small straw bale/ft² | 3% | 3% | 3% | 3% | 5% |
| % of bale per seed potato | 11% | 11% | 11% | 11% | 17% | |
| Containers | per ft² | 0 | 0 | 0 | 0.33 | 0.08 |
| ft² for each container | 0 | 0 | 0 | 3.6 ft² | 12.8 ft² | |
| seed potatoes per container | 0 | 0 | 0 | 1 | 3.6 |
Tomorrow we’ll look at yields and labor.
“Lab Notes” are a series of posts chronicling the progress our research projects. Research Project No. 2 is the testing of potato-growing methods. These notes may be useful for anyone interested in reproducing and testing our results. Others might be interested in just growing potatoes, and videos and other formal publications that will result from this research project will be posted to the website as they are available.