Harvesting Tomatoes for Storage

Harvested tomatoes for storage and ripening on November 2, 2011 (the first frost was predicted that night). We picked over a hundred tomatoes, most of which were still green.

We decided to experiment with different methods of ripening. Some were left on the vine, while others were picked and stems removed, and some were left of the plants to see if they would survive the frost and continue to ripen outside.

The plan is to ripen some in the garage at a cooler temperature, while others we will bring inside to ripen more quickly. We will take pictures and detail how quickly they ripen under each condition.

I connected my ventilation control system in the garage to try to maintain the temperature as close to the 50-55 degrees F that the Bubels recommend in their book, "Root Cellaring" to keep the tomatoes "on hold" -- the ripening time is predicted at 28 days if the temperature remains at 55 F.

We'll keep you updated on the progress of the tomatoes.

Vegetable Storage Guidelines

Ideal storage conditions vary for each vegetable.

Crop	Temp.	Humidity
Potatoes	38-40 F	90%
Carrots	32 F	90-95%
Onions	32 F	65-70%
Beets	32 F	95%
Squash	50-55 F	70-75%

Preparing foods for storage

• Details coming soon on each vegetable

Storage height affects temperature

• Details coming soon on recommended storage heights for each vegetable

Principles of Operation

Root cellars utilize natural processes to create an ideal storage environment for vegetables, specifically root crops (by definition). Before the days of refrigeration, cellars were the only option for storing crops beyond their season. The key parameters that lengthen storage life are temperature, ventilation, and humidity.

Temperature

• Ideal temperature range for most vegetables if 32 -40 F
• Borrow cold by digging into the ground
• Keep cold by designing the cellar to trap cold air

Ventilation is key

• Helps regulate temperature
• Removes gases that hasten spoilage
• Low intake vent, high exhaust vent creates natural air cycle

Humidity

• High humidity keeps vegetables from shriveling
• A dirt floor utilizes moisture in the ground to keep humidity high
• Misting the walls or leaving out pans of water will keep the cellar moist

Introduction

The purpose of this blog is to serve as a one-stop reference for anything related to root cellars.

Posts to be added/updated in the near future include:

• History of root cellars
• Principles of operation
• Guidelines for storing foods
• Cellar designs
• Ventilation systems
• Preparing foods for storage
• Root cellar resources
• Success stories
• Discussion forum
• My interest in root cellars

My Interest in Root Cellars

Always having had a desire to be self-sufficient, my parents had space for an under-the-porch root cellar included in the home they had built in the mid 1990s. The cellar is 6' x 6' with a 10' ceiling, a dirt floor, and concrete walls on all sides (the wall against the basement has a doorway for entrance from the basement). For years this space sat vacant as no one in the family understood the purpose of a root cellar and the principles that allow storage of root vegetables through the cold months of winter. Fifteen years later, as my parents are working to finish the basement to make room for grandchildren, the question of "what to do with the root cellar" has arisen again. Having always been curious about how root cellars work, when home for Christmas in December I volunteered to research root cellaring and determine how to turn the "shed attached to the basement" into a storage room for the vegetables harvested from the family garden each fall.

I jumped on the internet and within an hour learned the basic principles of root cellar operation. I learned that the ideal temperature for the root cellar is 32 - 40 F. I learned the importance of having vents to allow cool air to fall into the cellar and warm air to escape. I learned how building custom shelving allows you to store different vegetables at heights that correspond to their ideal storage temperature within the cellar. I learned that keeping the humidity as high as possible (90-95%) prevents vegetables from shriveling. And I was fascinated to find out how an ideal root cellar utilizes natural processes to keep temperature and humidity at their optimum values.

For example, warm air rises and cool air falls. Thus, having a cool-air intake vent at the bottom of your cellar and an exhaust vent for warm air at the top of your cellar facilitates a ventilation cycle as cool outside air falls into the cellar and warm air escapes through the exhaust vent. Opening these vents when it's cool outside and closing them when it's warm is an additional measure that keeps the cellar as cold as possible. For humidity, the ideal cellar has a dirt floor which allows the moisture in the ground to regulate cellar humidity. Additional measures such as misting the walls of the cellar or leaving out a pan of water help keep humidity high.

I truly appreciate these natural processes and the way they've allowed people to store vegetables for hundreds of years. But as an engineer by training, however, my initial thought was that root cellar performance could be improved by the installation of a simple control system. For example, an automated system that opens and closes the intake and exhaust vents and turns on and off a ventilation fan depending and outside temperature would improve performance. Adding a humidification system to maximize relative humidity would be an additional benefit.

If a traditional root cellar allows the storage of vegetables from November through March, how long could root crops be stored in a cellar with a ventilation/humidification control system? September through April?

The purpose of this blog is to document (1) the construction of my parents' under-the-porch root celler, (2) the performance of the root cellar utilizing natural process climate control, and (3) any improvement in performance afforded by a ventilation control system.