Obviously, with decreased space limitations, yields will increase. Just how much they increase depends upon who is consulted. My father has gardened in raised beds for over 20 years and has records for each year. He will tell you that you can expect at least double the yield of the same amount of space in a traditional type of garden (personal interview). Pete Lane asserts in an Ohio State University Extension Fact Sheet that In a traditional home garden, good management may yield about 0.6 pounds of vegetables per square foot. Records of production over three years in a raised bed at Dawes Arboretum near Newark, Ohio, indicate an average of 1.24 pounds per square foot, more than double the conventional yield.
Dan Wallace, editor of Getting the Most from Your Garden, presents a table on page 7 that compares national average yields using the traditional method with the yields from John Jeavons experiments with raised beds at Ecology Action of the Mid-Peninsula in Palo Alto, California. That table is partially reproduced below.
national average yield
Growing Bed Average (lbs./100 ft.)
Beginner Intermediate Advanced Bean, snap 8.2 30 72 108 Broccoli 17.4 39 72 108 Carrot 58.9 100 150 1,080 Corn 15.3 17 34 68 Lettuce, head 48.6 75 150 300 Lettuce, leaf 48.6 135 202 540 Onion 68.6 100 200 540 Pepper 18.8 36 83 131 Tomatoe 30.7 100 194 418
Offered by Roger.