Thursday, November 21, 2013

Keeping Your Harvest

By Master Gardener Marianne McNiel

As gardens produce the last of their late fall bounty, you may want to think of ways to store some of your root vegetables and squash from your own garden or from your local farmers’ market. That way you will have some fresh vegetables for much of the winter. So what types of root vegetables or squash can be stored for late fall and early winter consumption? There are many! Some call them “keeper” crops.

Winter Squash

Winter squash is harvested when there is a corking of the stem and loss of rind surface sheen. There is also dieback of tendrils and leaves closest to the fruit. Leave the stem on the squash for storage because this will reduce disease. All squash should be harvested for storage well before our first frost. Temperatures below about 50oF will cause squash to experience chilling injury.  If your winter squash has experienced many days below 50oF, you may want to wait until next year for storing it for later consumption.

Winter squash can be stored until January, February or March. Butternut squash may last even longer. Select squash that are disease free and have few blemishes. They should be stored in a cool, dry, well-ventilated place with a relative humidity of 50-70%. Highly humid and moist environments may cause the squash to develop fungal or bacterial organisms that will hasten their decay. A very dry environment will cause the squash to dehydrate. If you have a basement, it may serve as the best place to store winter squash. If you have a dehumidifier in your basement you can set it to around 50% humidity.  Winter squash is best stored off the ground. Some gardeners store them on wooden trays or racks that can be stacked.

Root Vegetables

When storing root vegetables, you should keep them away from apples, pears or tomatoes. These fruits produce ethylene gas and can make the taste of some root vegetables bitter. Also, do not store onions and winter squash with potatoes since the moisture and gases released from the potatoes will hasten their decay.

Carrots, Beets, Parsnips and Winter Radishes

When you are planning to store your root crops, you may want to leave them in the ground until the first frost. Root vegetables for late fall or winter storage should be harvested when fully mature and they should be free of blemishes and disease.
Harvest carrots when the roots are an acceptable size usually about ¾ to 1 inch in diameter. Beets are harvested when they are between 1 to 2 inches in size.  Parsnips can be harvested directly from the ground all winter since they are winter hardy. However, it will be difficult to dig them once the ground is fully frozen.  Radishes mature very quickly and should be pulled from the ground once mature for best flavor.

Ideally, these root vegetables are best stored at slightly above 32oF and a relative humidity of 95%. This is quite a damp, cold environment, but when stored properly, they will last for most of the winter.
Other root vegetables like turnips, rutabagas and spring radishes also do best stored at low temperatures, slightly above 32oF and high humidity.  Turnips and rutabagas will only last about a month and spring radishes will only last about one week.

Potatoes are harvested after the vines have fully died. When growing potatoes, you can check for maturity by digging up one hill to determine if the skin remains fully attached to the tuber when rubbed.  Potatoes store best when the skins are at this level of maturity. You should be careful not to damage tubers at harvest. Any damaged potatoes should be eaten or discarded and are not suitable for long term storage.

The ideal temperature for storing potatoes is between 45 and 50oF. Below 40oF, the starch in the potatoes will turn to sugar and they will develop a sweet taste. Above 50oF, the potatoes will sprout.   Potatoes also require a high relativity humidity of 90 to 95% for proper storage. Like root vegetables, potatoes prefer this cold, damp environment.

Garlic and Onion

There is only a 10 to 14 day window for optimum garlic harvest. Garlic is also best harvested in cool weather for optimal taste. When the leaves start to brown, pull a sample to determine its progress. If you dig the garlic too early, the garlic will not be segmented into cloves. If you dig the garlic too late, the cloves will have grown and expanded and the outer sheath will be split. The bulb should not be split and should have a tight skin for best storage. Onions should be dug when the tops are completely brown at full maturity.

Allow onions and garlic to dry in a well-ventilated area about 70 to 75oF that is protected from sunlight. Sunlight will hasten their decay and cause color changes. A warmer temperature may cause the onions and garlic to caramelize.  After drying, trim the roots and tops 1 inch from the bulb. Breakdown in storage may result if the tops are cut too close to the bulb and the neck is not thoroughly dried. Close cutting allows decay organisms to have easy access to the bulb.

Onions and garlic are best stored between 35 to 40oF and a much lower humidity than potatoes or root vegetables. These vegetables are best stored in a dry, dark, well ventilated place; not in the refrigerator.  A basement with adequate ventilation will work well for this purpose. Avoid storing onions and garlic where they will be exposed to moisture and high humidity.

A Final Word
Do low storage temperatures mean you need a root cellar? Maybe. But there are other options.  Some folks dig a trench and store root vegetables there. Below, there is a link to a Penn State Extension article about storing root vegetables in a trench. Some gardeners store in a separate refrigerator set to the temperature and humidity required. Of course, this requires running an extra refrigerator and this may not be possible for many homeowners. Onions and winter squash can be safely stored in a cool basement or garage that is insulated so the temperature does not fall below freezing. For optimal storage, potatoes and other root vegetables need colder storage and that is where a root cellar comes in handy. If you are in a Co-Op or a Community Agricultural Support (CSA) program, you may already have access to a root cellar. In an upcoming blog I will discuss more about farms that participate in CSA programs and some newly formed Co-Ops.

Just remember, if you are planning to store vegetables for late fall or winter, they should be harvested when fully mature and they should be free of blemishes and disease.

A link to a Penn State extension article about harvesting and storing winter squash and pumpkins:

A link to a PSU extension guide about growing root vegetables:

A link to information from PSU extension about storing potatoes:

A link to a PSU extension guide for growing bulb vegetables:

Storing root crops in a trench:

Support Your Farmer

Great Bend Farm, located in Port Clinton, offers a Winter CSA starting in late November and runs through April.  Their shares contain onions, squash, potatoes, herbs, greens, root vegetables and more!

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