Root Cellar Construction

Food Farm Storage Facility: An Example

Food Farm is a 200-acre community-supported agriculture farm located in Wrenshall, Minnesota. It has 100 summer vegetable shares, 36 winter vegetable shares, pastured poultry, and egg shares. The farm is run by John Fisher-Merritt and his family according to the biodynamic philosophy. The farm also wholesales certified organic vegetables to the Whole Foods Co-op in Duluth.

Food Farm installed automatic temperature control and a monitoring system in their rootcellar.

Food Farm received a sustainable agriculture grant from the Minnesota Department of Agriculture (MDA) to fund this project. Read about this on the MDA website starting on page 34 in the 2004 Greenbook.

Above, John (with black cap) and Jane Fisher-Merritt (on right with back to camera) held a tour of their rootcellar on August 5, 2001.

This box (above) is hooked up to to the computer that monitors, records, and adjusts temperatures in the storage areas.

When necessary, this vent (above) opens to increase air flow to a storage bin or room.

There are 3 storage rooms kept at different temperatures - one room for rutabagas, parsnips, and carrots, another room for squash, and a third room for onions and potatoes.

View more photos from inside the root cellar.

Performance

How well did the rootcellar perform in the 2001-2002 season? Here's the data taken at the beginning of March:

Commodity Food Farm University Cooler
Rutabagas
  • 14.6% weight loss
  • Sprouting
  • 65.6% loss (50% RH)
  • No Sprouting
Delicata Squash
  • 18.% weight loss
  • Rot (45 F)
  • 35.2% weight loss
  • No rot (50 F)

Carrots from Food Farm had an average brix of 8.52 (5 carrots sampled) in late October. In early March, the average brix was 7.96 (5 carrots sampled).

At harvest in 2003, Food Farm carrots had an average brix of 7.35 (10 carrots sampled). The brix did not change with storage. The average brix of Food Farm carrots in February 2004 was 7.5 (10 carrots sampled).

Graphs of the temperature data for September 2001-February 2004 are available for the Food Farm root cellar.

Cost

Cost breakdown for the construction of the Food Farm root cellar:

Activity Cost Breakdown Totals
Excavation
  • Road and Pad: $2,250
  • Basement: $2,785
$5,335
Concrete Drains
  • Miscellanous pipes, etc: $725
  • Walls and slab: $8,340
$9,155
Temperature Control System
  • Computer Hardware: $111 
  • Installation: $3,150
$3,261
Construction
  • Labor: $6,000
  • Electrical Labor: $1,240
  • Materials: $10,581
$17,847
Grand Total $35,598

Design

A detailed schematic of the insulation is shown below.