- Author: Jim Muck
Fall has just begun, so now is the time to harvest all those winter squash you planted way back in May or June. To ensure the squash are marketable over the winter they must be handled correctly so that the quality of the produce remains high. Missteps along the way from field to final sale can make the difference between a long profitable winter sales season and a very short unhappy season. Improper harvest or storage can result in spoilage therefore wasting all the farmer's time, effort, and money. Luckily storage of squash is pretty easy as long as the farmer pays attention to three things.
Temperature, humidity, and ventilation are the three things that a farmer can control during storage. Winter squash will store very well at temperatures between 50°F to 55°F. Do not allow the storage temperature to dip below 50°F! At temperatures below 50°F chilling injury can result. Winter squash stored in the chilling injury range can look fine in storage, only to decay rapidly once removed from storage. Humidity is very important to maintaining high quality squash. Maintaining a relative humidity range of 50% to 70% is key to long term storage success. Good ventilation is also required. Stagnant air, even at the right temperature and humidity, will lead to shortened storage time. What is a farmer to do? This all sounds so complicated and technical! It is complicated and it is technical, but it is also doable with just a few simple steps.
Here is a list of what you can do:
- Find a space that is free of rodents and other pests. The space needs to have electricity so you can control the temperature, humidity, and ventilation. If you have a walk-in cooler that you do not use in the winter, it will work great. Just make sure you can ventilate the space.
- Know your squash. Did you grow butternut, acorn, Delicata, and/or Hubbard squash? Some varieties store better and longer than others, but all varieties do store at least for a number of months. According to Oregon State University Extension Service, acorn squash has the shortest storage life (1 to 2 months), Hubbard has the longest (3 to 6 months), and butternut is in between (2 to 3 months). Please note that these storage times refer to how long the squash stay at optimal eating quality. You can store acorn and butternut for longer periods of time, but as time passes, there will be a decline in the eating quality.
- Harvest your squash once the skin has hardened and you can't puncture the skin when you press on the squash with your thumbnail.
- Harvest gently! One of the keys to long storage is gentle handling at the time of harvest. Cuts to the skin or punctures dramatically reduce the storage potential of the squash.
- Harvest the squash before you have your first freeze. Freezing will cause chilling injury and a squash that looks fine in the field can decay rapidly in your storage area. The decay can quickly spread to other stored squash.
- Treat the squash gently in your storage area, too. Ideally you would be able lay all of your squash on ventilated shelving in a single layer at least 12 inches off the floor. In the real world you are going to need to stack the squash because you won't have enough shelf space. Try not to stack squash more than two layers high on shelving or in boxes. Avoid storing in sealed boxes and avoid putting your storage containers directly onto a cold concrete floor.
- Do not store apples or pears with your squash. These fruits emit ethylene gas that will cause your squash to yellow and shorten the shelf life.
- If you find a squash that is showing signs of decay remove it immediately and check your storage conditions – temperature, ventilation, and humidity and adjust accordingly to maintain optimum conditions.
With all the above in mind you are on your way to having a great storage season. To achieve the optimal storage conditions listed above, you will need a few items and some ingenuity. To maintain temperature you can use a space heater that has a settable thermostat that goes as low as 50 degrees. To ensure adequate ventilation, you can use a simple box fan or oscillating fan. Just be sure you have a way of allowing outside air to enter and exit your storage area. If you are using a walk-in cooler you will need to install a small vent. Otherwise you will need to open the door to your cooler multiple times a day to provide fresh air. To control humidity use a room humidifier that has an adjustable humidity control (humistat).
So there you go, that wasn't too bad was it? All you need to do now is spend some time setting up your storage space. Once you have the space ready, get out there and harvest that crop you have nurtured through the long, hot summer.