Store Garden Produce #9-How To Build A Cellar-Part 1
The year round availability of fresh produce at supermarkets in this modern society has pretty much eliminated the use of the historic age-old root cellars. It appears that all that remains of its existence are the fond childhood memories of that deep dark scary place known only to a kid as a fort! However, as more people are reverting back to the basics of home gardening, there is a revitalization of the good old-fashioned root cellar. It has been reborn into an indispensable addition. You can easily build a root cellar in your very own basement, outbuilding or even as an outside pit. This article covers root cellars and is not inclusive. It should be shared with Kali’s Store Garden Produce Series #1-10. Store Garden Produce #10 covers root barrels, outbuildings and storage pits.
In the root cellars heyday, our ancestors used cold storage to keep food fresh when temperatures made it advisable for produce to be stored underground. Root cellars were the basic equivalent of today’s refrigerators. Nowadays, those dedicated to eating locally often preserve foods at the height of the season when produce is less expensive and more nutritional compared to buying food in the dead of winter when produce is an expensive commodity.
Root Cellaring: A root cellar is any storage area that uses the earth’s natural resources to cool, insulate and humidify the produce stored within. They are earth-friendly, non-polluting and require no electricity. To work properly, a root cellar must be able to hold temperatures of 32º to 40º F and maintain a relatively humidity level of 85 to 95 percent. A good quality hygrometer will check for humidity and temperature levels within various locations within the home, whether it be an unused storage room, basement or back porch. While the ideal root-cellar combination for fresh foods is low temperature and high humidity, the worst situation would be high temperatures and high humidity. This situation nurtures bacteria, mold and yeast. Therefore, a root cellar requires high humidity only for its ability to maintain freshness. Low temperatures (above freezing) are then needed to counter balance the bacteria and mold problems created by high humidity. Cool outdoor air circulation is also a requirement to regulate the conditions of the stored produce.
Maintaining Proper Humidity Levels: The main culprit for shriveling of produce in storage is low humidity. A dirt, sand or gravel floor is the best option for maintaining proper humidity control as well as for proper drainage. To raise the humidity of the storage air, the floor can be sprinkled down. Gravel floors provide the best “humidifiers” in this instance, especially if the gravel is several inches deep so that it is able to hold some water at the bottom. While most produce like moist conditions, standing water must be avoided. It will quickly decay your contents. Assess your own specific situation. Homeowners in the south might even consider installing a cellar sump pump or other drainage alternative if you happen to have a high water table.
For dirt or sand floors, place water in shallow pans under fresh-air intake vents to increase humidity levels. You can also pack root vegetables in damp sawdust, sand or moss to reduce surface evaporation. Covering food with dry burlap or towels can absorb some of the moisture in the air. If the air becomes too dry, dampen burlap cloths or pack root vegetables in wet sawdust to help increase humidity levels. Use your hygrometer daily!
Some root cellars wisely include two rooms, one with and one without a concrete floor. Concrete floors provide slightly lower humidity levels and are typically utilized in basement root cellars. Concrete floors are best when storing dry goods, grains, beans as well as some fresh foods such as pumpkins, onions and squash. In addition to proper temperature and humidity, all fruits and vegetables must be kept in a dark, ventilated environment. Produce must not be allowed to freeze and should be protected from rodents such as mice.
Maintaining Proper Temperature: The first consideration to provide longevity to root vegetables is to lower the storage temperature to 32° to 40° F (0 to 4 C). The goal of storage is to keep produce in a dormant state. Temperature can be regulated using 2 types of a ventilation system to the outside, either through one or two windows or by using 2 separate venting pipes. Both options allow cold air in and warm air out. Without proper ventilation for air circulation to control temperature, your stored produce will spoil. You don’t want a strong draft; however for this will remove moisture from the produce.
Cellar Ventilation: You need to install two pipes vented to the outside; one at the lowest point of the room and one at the highest. Both pipes should be a minimum of 3 inches in diameter. Cool air is denser than warm air and will collect in the low areas. Anytime the air outside your root cellar is cooler than the air inside, the air transfer from one pipe to the other will allow a heat exchange: cool air is drawn in while warm air is vented out. As outside temperatures fluctuate, you will be able to maintain continuous airflow to regulate the temperature as low as possible. Sites that include at least two windows on opposite sides of the root cellar are the least expensive to maintain and are more desirable in creating proper ventilation, particularly if the room is divided for separate dry storage goods.
The warm air pipe can be vented out the window, equipped with a elbow, at the highest point while the cool air pipe can go through the wall at any location just as long as there is an elbow attached to a length of pipe running down the inside so that it ends up about a foot from the floor. The elbows should be loose fitting since you want to be able to rotate the elbow toward the incoming wind…or direct it away from it. An alternative is to just add blast gates to each pipe. The two vents or pipes will create a siphoning effect. When the temperature outside goes below freezing, one of the gates or valves should be closed or turned from the wind. You will receive reduced venting but it will keep the produce from freezing. If the outside temperature goes below 32° F or 0 C, the freezing level, you’ll need to partially close both valves. Make sure to seal the wall or window around the pipes with aerosol insulating foam. This will fill in any gaps or cracks. Once it sets, it does a great job of holding the pipes in place. A finishing touch is to fasten a rod as a handle for each blast gate and run it through the outside wall of your cellar. This way you can open and close the valves as well as see the valves in their position without having to open the door to release the cold air. Additionally, shade the windows in a way that will prevent light from entering the cellar. Only a small amount of heat is necessary to prevent subfreezing temperatures. A light bulb left on during the coldest days provides just enough heat to keep the air above freezing. However, if you do keep it on, be sure your produce is covered with heavy cloth as protection against light and condensation, especially for potatoes!
How to Make a Cellar: You will need to consider the location of your root cellar. Some root cellars are built into hills and buried on three sides with a normal, walk-in door on the unburied side. Others are completely buried and must be entered by stairs often accessed through a door in the ceiling. If maximum coolness is a priority, as it will be in the south, then bury the cellar completely. As an alternative to a ceiling entrance, a stairwell can be dug just outside a cellar wall with a landing at the bottom, where an insulated door can be installed leading into the cellar. Keep that door out of the sun and away from any hot summer breezes. Too large of a room can become unstable over time. It may be better to build more than one if you need more room. Site your underground room in a place away from drains or other areas that may trap water. You need a good roof that doesn’t allow moisture to penetrate the cellar. It also needs to be structurally sound in order to cover the roof with at least 2 feet of soil. Dirt is the cheapest insulating material available; so do not skimp on adding more dirt. When the cellar is completely covered, scatter grass or flower seeds. Mint makes an excellent groundcover. Mint grows vigorously and produces a thick and binding root system to hold the soil in place.
When choosing a basement location, consider partitioning off the farthest northwest corner, preferably closest to the sump pump for additional humidity and one located by windows for ventilation as discussed above. Avoid heat ducts and hot water pipes that would generate heat. It will provide the coolest, dampest, darkest storage area. If located near a furnace, you can easily patrician off a section for dry storage such as grains, onions, garlic, squash and pumpkins as well as being able to insulate the actual root cellar within.
Insulating a Cold Cellar: A space eight-by-eight feet should be plenty room for the average family The best method is to use the foundation walls on the northeast corner for two sides then build the other two walls in the basement with stud and board. Due to the moist conditions, you should make the walls out of 2X4s made of cedar or other rot-resistant wood for framing as well as some moisture-resistant wall board such as “green board” used in shower stalls. While the exterior walls do not need to be insulated, the inside partitions should have 3½” thick fiberglass insulation. Faced insulation should have the vapor barrier closest to the warm side of the storage. If unfaced insulation is used, a vapor barrier such as 6-mil thick polyethylene can be used. The ceiling also requires insulation and a vapor barrier. Then it is time to apply the foam aerosol insulation to any nooks and crannies. You want the room to be as air tight as possible.
Root Cellar Door: One customized feature worth noting is to construct a door in two pieces, called a Dutch door that splits across the middle. You are able to access the bottom door when temperatures are warm and the upper section when temperatures are cold. This way you can open the upper half to grab a few items without letting out the coldest, dampest air at the bottom of the root cellar. Double-doors or a small anteroom (fore-room) provide an additional degree of protection from temperature swings.
Cellar Rack: Keep in mind that lower shelves will be cooler and wetter, higher shelves will be warmer and dryer. Arrange and space your shelves to suit the items that will likely be stored on them. Wooden wall shelves, bins, and pallet shelving is recommended, as wood does not conduct heat or cold as rapidly as metal shelving units. Do not use aluminum shelving which tends to cause condensation. Although moisture is good, icicles or water droplets are not. When you place the cellar rack, do not let the rears of shelves contact the cellar walls, as this restricts air circulation. Air circulation is critical for minimizing airborne mold, so shelves should stand 1 to 3 inches away from the walls.
Store vegetables and fruits in wood crates or boxes rather than in bins. Slatted crates for better air circulation utilize space more efficiently than baskets. Use containers that have smooth inner surfaces. Protruding wire staples in baskets and hampers are particularly damaging to a crops outer skin. Lightweight tub buckets are good containers for harvesting as well as standard apple and lug boxes used for shipping tomatoes, grapes, and nectarines.
Vegetables that are piled together will generate heat. Only stack 2-3 layers within any one container. You will want to place some of the crops on the cellar racks while others can be placed on pallets on the floor–always rotate or “air” your crops accordingly. Some crops such as potatoes, apples or pears can be covered in straw or individually wrapped in newspapers to retard ethylene gas discussed in Store Garden Produce #8.
Find Additional Information on How to Build a Cellar Here!
Root Cellaring Temperature & Humidity Chart Here!
Follow all 10 Parts of Kali’s Store Garden Produce Series 1-10 Here!
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Kali S Winters
Root Cellar Temperature-Humidity Chart
How long can certain vegetables be keep in the garden soil before the cold weather demands their removal indoors? Generally, the less susceptible they are to frost, the longer you can keep the vegetables in the ground by using a 12-18-inch covering of mulch. You might consider building a two-to-three foot wall all around the garden to keep the cold winds off the plants during this period that you are stretching their garden life. This will also keep all your mulch from blowing away. The wall can even act as a solid foundation for a temporary greenhouse frame that you could quickly erect and drape with inexpensive plastic film, to keep the plants in their garden soils even longer.
Check out Kali’s 10 Part Series on Store Garden Produce Here!
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Kali S Winters
| Table 1
Fruits & Vegetables that require cold, moist conditions |
Temperature (oF) | Relative Humidity (%) | Length of Storage |
| Asparagus | 32-36 | 95 | 2-3 weeks |
| Apples | 32 | 90 | 2-6 months |
| Beets | 32 | 95 | 3-5 months |
| Broccoli | 32 | 95 | 10-14 days |
| Brussels Sprouts | 32 | 95 | 3-5 weeks |
| Cabbage, Early | 32 | 95 | 3-6 weeks |
| Cabbage, Late | 32 | 95 | 3-4 months |
| Cabbage, Chinese | 32 | 95 | 1-2 months |
| Carrots, mature | 32 | 95 | 4-5 months |
| Carrots, immature | 32 | 95 | 4-6 weeks |
| Cauliflower | 32 | 95 | 2-4 weeks |
| Celeriac | 32 | 95 | 3-4 months |
| Celery | 32 | 95 | 2-3 months |
| Collards | 32 | 95 | 10-14 days |
| Corn, sweet | 32 | 95 | 4-8 days |
| Endive, Escarole | 32 | 95 | 2-3 weeks |
| Grapes | 32 | 90 | 4-6 weeks |
| Kale | 32 | 95 | 10-14 days |
| Leeks, green | 32 | 95 | 1-3 months |
| Lettuce | 32 | 95 | 2-3 weeks |
| Parsley | 32 | 95 | 1-2 months |
| Parsnips | 32 | 95 | 2-6 months |
| Pears | 32 | 95 | 2-7 months |
| Peas, green | 32 | 95 | 1-3 weeks |
| Potatoes, early | 50 | 90 | 1-3 weeks |
| Potatoes, late | 39 | 90 | 4-9 months |
| Radishes, spring | 32 | 95 | 3-4 weeks |
| Radishes, winter | 32 | 95 | 2-4 months |
| Rhubarb | 32 | 95 | 2-4 weeks |
| Rutabagas | 32 | 95 | 2-4 months |
| Spinach | 32 | 95 | 10-14 days |
|
Table 2 Vegetables that require cool, moist conditions |
Temperature (oF) | Relative Humidity (%) | Length of Storage |
| Beans, snap | 40-50 | 95 | 7-10 days |
| Cucumbers | 45-50 | 95 | 10-14 days |
| Eggplant | 45-50 | 90 | 1 week |
| Cantaloupe | 40 | 90 | 15 days |
| Watermelon | 40-50 | 80-85 | 2-3 weeks |
| Peppers, sweet | 45-50 | 95 | 2-3 weeks |
| Potatoes, early | 50 | 90 | 1-3 weeks |
| Potatoes, late | 40 | 90 | 4-9 months |
| Tomatoes, green | 50-70 | 90 | 1-3 weeks |
| Tomatoes, ripe | 45-50 | 90 | 4-7 days |
|
Table 3 Vegetables that require cool dry conditions. |
Temperature (oF) | Relative Humidity (%) | Length of Storage |
| Garlic | 32 | 65-70 | 6-7 months |
| Onions | 32 | 65-70 | 6-7 months |
| Table 4
Vegetables that require warm dry conditions. |
Temperature (oF) | Relative Humidity (%) | Length of Storage |
| Peppers, hot | 50 | 60-65 | 6 months |
| Pumpkins | 50-55 | 70-75 | 2-3 months |
| Squash, winter | 50-55 | 50-60 | 2-6 months |
| Sweet Potato | 55-60 | 80-85 | 4-6 months |
Additional Tips:
- ·Apples: I don’t foresee growing these, but they’re considered the ‘queen’ of storage fruits.
- ·Beets: good keepers. The ‘Long Keeper’ variety is just that — a great keeper. The leaves are vitamin-rich. Can last 4 to 5 months in storage.
- ·Brussels sprouts: might keep 4 to 5 weeks if kept in perforated plastic bags. This reminds us we might want to stock up on plastic grocery bags for this purpose.
- ·Cabbage: if it splits, it won’t keep.
- ·Chinese cabbage: can last up to three months. You can even replant them in a box of soil in the root cellar.
- ·Carrots: a summer planting is best for winter keeping. They are the backbone of any food-storage plan. The roots are rich in vitamin A and they can last several months in storage. With adequate mulching, you can even keep them right in the garden row for the winter.
- ·Cauliflower: keeps only a short time at best, two to four weeks.
- ·Celeriac: a good keeper.
- ·Celery: see how late you can keep this in the garden, and then maybe you can get a month or two of storage out of it.
- ·Garlic: needs lower humidity than root vegetables. If you can find a cool, dry place, it can last seven or eight months.
- ·Horseradish: very hard and a good keeper.
- ·Jerusalem artichoke (sunchoke): can last several weeks in plastic bags or in damp sand.
- ·Kale: high in vitamin content, easy to grow, extremely cold-hardy.
- ·Kohlrabi: the leaves are good to eat. Packed in damp sand or sawdust, it can keep well into the winter.
- ·Leeks: especially cold-hardy. Can make it through a winter outdoors if well mulched, or you can plant some in your root cellar in tubs of sand or soil.
- ·Lettuce: has a short storage life.
- ·Onions: seed-grown onions are especially good for storage.
- ·Parsnips: these are perhaps the hardiest of all root vegetables. Be sure to dig them out. If you pull them, you can lose half the root. If you nick the roots with the shovel, don’t store them. Nicks and blemishes invite spoilage, and this applies to all root vegetables. For longer storage, pack them in damp sawdust. Leaves, moss, or sand will work well too. The leaves are edible.
- ·Sweet Potatoes: the roots are vitamin-rich, and they can keep several months if stored well. Must be cured.
- ·White Potatoes: beware of planting the kind you buy in the store — they may contain disease. Cool nights promote storage of starch, making for a longer-keeping potato, so the later-maturing ones are best for storage. Must be cured and kept in a dark spot. They can last four to six months.
- ·Pumpkins: those that have lost their stems won’t keep well.
- ·Winter radishes: they’ll last until February if well stored.
- ·Rutabagas (Swedish turnip): will last two to four months in storage.
- ·Squash: if it’s well stored, it will keep for up to six months. Cure them for 10 to 14 days. Like pumpkins, keep them dry and moderately warm.
- ·Tomatoes: late-planted tomatoes are best for storage.
- ·Turnips: these are among the hardiest of vegetables. In storage they might put out pale, leafy tops, good for stews.
Root Cellaring- Fresher Longer Food Storage
Root vegetables are named as such due to their underground plant parts that are eaten. They are easy to store and with just a few simple steps you can enjoy a bountiful harvest throughout the winter months.
- Root crops, including potatoes, carrots, beets, turnips, rutabagas, winter radishes, kohlrabi and parsnips, adapt best at near freezing with a high relative humidity.
- Root vegetables, such as potatoes, carrots and onions, have a long storage life. They require minimal preparation before storing.
- Root crops store best where they are grown until there is a danger of soil freezing. Postpone harvesting by tilling the soil over the shoulders of carrots and beets to protect them from freezing. If straw and soil are piled over the row as insulation, harvest may be delayed even longer.
- Bring most vegetables and fruits into the root cellar immediately after harvesting. Some vegetables, however, such as onions and garlic, need to be dried in the sun for a week before dry-cellar storage. Squash and pumpkins need two weeks in the sun to develop a hard rind, and they need a warm cellar. Sweet potatoes also need to be cured.
- Freezing is fine for some fresh vegetables and destructive to others, like potatoes. However, you will want to completely avoid repeated freezing and thawing that can take place in root cellars from a warm spell to a cold spell and back to warm. You can solve this problem if you build a section of your root cellar that never freezes during these wavering spells on either side of the winter deep-freeze.
- Store onions near freezing but with a low relative humidity to discourage neck rot.
- Parsnips will withstand freezing. Leave part of the crop in the ground and dig in the spring when the flavor has greatly improved.
- It is important to time your final harvest for the latest possible date. As well as planting vegetables as early as possible in the spring to be able to eat them in late spring or early summer, plant a sizable crop later than usual so that their peak arrives only in the nick of time before the killing frost. This late crop will represent your fresh supply of food throughout the winter.
- Take into account that vegetables planted later than normal will grow slower in the cooler months of fall.
- Kale and collards can be left in the garden long after the first fall frost. Harvest as needed until the foliage finally succumbs to cold weather. Wind protection will prolong its usefulness.
- Celery and late cabbage may be harvested after the frost has stopped their growth. Pull celery with its roots attached. Cut cabbage and remove the loose outer leaves.
- Plant lots of potatoes and carrots as they might last 4-6 months, but you would not want to plant too much broccoli since it only keeps for a couple weeks.
- Leafy crops such as celery and cabbage may also be stored. Store them by themselves — they give off ethylene gas while in storage, which has proven detrimental to other vegetables.
- Celery may be harvested and stored directly in trenches that are dug for that purpose. Pull the celery plants and pack them upright in the trench. Cover with paper, boards and soil. They will root, bleach, tenderize and develop a nutty flavor when removed in late December.
- Many cool-weather crops taste better after frost has nipped them. Among these are parsnips, salsify (also called “oyster plant”), kale, Brussels sprouts, collards, and Chinese cabbage.
- Potatoes grown in sandy soils last longer in storage than those grown in heavy soils.
- Fruits and vegetables grown in soil with high potash levels store better and longer than others. Wood ashes are a good source of potash.
- Store the ashes all winter long where the wind won’t blow them away, and any manure your animals provide can be collected at the first thaw, but don’t over-dose your garden soil.
- Beets 4-5 months
- Broccoli 1-2 weeks
- Brussels Sprouts 3-5 weeks
- Cabbage (long keeper)
- Chinese Cabbage 1-2 months
- Carrots 4-6 months
- Cauliflower 2-4 weeks
- Celery (long keeper)
- Chives (not a root-cellar crop)
- Collards 1-2 weeks
- Cucumbers 2-3 weeks
- Eggplant 1-2 weeks
- Horse Radish (long keeper)
- Jerusalem Artichokes 1-2 months
- Kohlrabi (long keeper)
- Leeks N/A
- Onions (good keeper)
- Parsnips 1-2 months
- Pepper (good keeper)
- Sweet Potatoes (long keeper)
- Potatoes 4-6 months
- Pumpkin (good keeper)
- Radishes 2-3 months
- Rutabagas 2-4 months
- Salsify (good keeper)
- Soybeans (long keepers)
- Squash 4-6 months
- Tomatoes 1-2 months
- Turnips (long keepers)
The following are root-cellar products that are best stored in cold and very moist conditions (32-40 º F and 90-95% relative humidity): Beets, collards, broccoli, Chinese cabbage, carrots, turnips, radishes, rutabagas, parsnips, Jerusalem artichokes, celery, salsify, celeriac, parsley, Brussels sprouts, leeks, and kohlrabi.
The following products do best in the same temperatures but at a slightly reduced humidity (80-90%): Potatoes, endive, escarole, cabbage, cauliflower, quince, apples, pears, oranges, grapefruit, and grapes.
The following do best in 40-45º F cellars with a relative humidity of 85-90%: Cucumbers, cantaloupe, eggplant, tomatoes, watermelon, and sweet peppers.
Reduce the temperature and humidity of the following vegetables (35-40 º F and 60-70%): Garlic, onions and green soybeans in the pod.
The following need high temperatures and lower humidity (50-60 º F and 60-70%): Hot peppers, sweet potatoes, pumpkins, winter squash, and green tomatoes.
Very Susceptible to Frost:
Cucumbers, Eggplant, Lettuce, Squash, Sweet Peppers, Sweet Potatoes, Tomatoes, Pumpkins.
Moderately Susceptible to Frost:
Beets, Broccoli, Cabbage (young), Carrots, Cauliflower, Escarole, Garlic, Onions, Celery, Spinach, Parsley, Peas, Radishes.
Least Susceptible to Frost:
Brussels Sprouts, Cabbage (mature), Collards, Kale, Kohlrabi, Parsnips, Salsify, Turnips
For squashes, sweet potatoes and pumpkins shelves near furnace afford good storage.
Check out Kali’s 10 Part Series on Store Garden Produce Here!
Learn How to Start a Vegetable or Herb Garden-Free Bonus e-Books Here!
Successful Gardening!
Kali S Winters
