In my last newsletter article I talked about some general post-harvest handling of summer crops after they had been harvested from the field. Now that fall is here and storage crops are coming out of the field, I thought it may be helpful to discuss how to get the most  out of these. With winter markets becoming more and more common, there has been a renewed interest in growing storage crops for direct sale throughout the winter. Curing and storage of these crops can make a big difference in quality throughout the winter months.

Potatoes

We grow a lot of potatoes, both because I love to eat them and I think they are a lot of fun to grow. One of the things that I think is really neat about them is that you are the first person to ever see them when they are getting dug. It is a lot like a treasure hunt, and who does not like finding a surprise every once in a while?

While the potatoes are growing, the skins are very thin and fragile, and are not suitable for long term storage. The skins need to be set before they are ready to dig. The death of the plant sends a signal to the potatoes to go dormant. You can either let the plant die naturally, or do what’s more commonly done, kill the tops. Conventional growers typically do this with a chemical that kills and desiccates the tops. Organic growers have different options. We lop ours off with a weed whacker. It takes a little time, but does a better job than a mower. I have never gotten my mower to work well for this purpose. Another option is to flame the tops off, but depending on the health of the plants it may take more than one pass. One consideration is that when you are trimming tops or mowing, you are also creating millions of injuries that can allow the spread of disease. We always time our topping so there is a long stretch of hot and dry weather, this ensures plants wounds will dry quickly and lessen the chance of infection. After the tops are removed, a minimum of two weeks is required for the skins to thicken. I wait a third just to be sure. Then they are set for harvest and long term storage.

After we dig them, we leave them on the soil surface just long enough to have the skins dry. We then put them in bushel baskets in our “cold room,” an insulated room next to our cooler. I allow cool air in at night time to keep the temperature at 55- 60°F for 3-4 weeks. This gives the potatoes a chance to heal any bruises or cuts that happened during harvesting. For long term storage we lower the temp to 38°F. We have used a root cellar that also worked well, but found the physical moving of potatoes was not very fun. Now we move them in and out of our walk-in in the barn, which gives us much more time and energy to eat them!

Onions

The harvesting of onions is also subject to the condition of their tops. It is important for the tops and necks to be as dry as possible before they are topped and brought in. Some varieties that have thin necks down really quickly and can easily be pulled from the bulb. Unfortunately the ones I choose to grow do not do this easily. I have had problems with Alternaria and Botrytis in my onions for some time, so I choose varieties that have really good resistance to these diseases but may not dry down quickly or have thin necks. My experience is that they also hold onto their greens longer than most varieties too.

Most growers simply let their onions dry down in the field and come through and top as they harvest. You can also undercut the bulbs several days before harvesting when there is only a few green leaves left. Undercutting speeds dry down and will improve storage quality but relies on special equipment. Due to my particular situation I do things a little differently. I invariably walk the patch and push over the necks with my foot to encourage them to finish up. I seem to never get the weather I need for them to dry in the field either, so I bring them into a greenhouse and lay them on the benches a few deep to finish drying down and top them here. It’s extra work, but it feels like it pays to have them where I have more control. I keep them in the greenhouse for five or six weeks, ensuring they are well cured, and then I put them in a cool and dry spot for the winter in mesh bags. Be sure to gradually decrease temperatures, if decreases too quickly or fluctuates significantly it can cause bulb staining, sprouting or decay. Ideal storage temperatures area as close to 32°F as possible with out   freezing at 60-70% relative humidity.

Carrots and Beets

There is always the question of wether to wash or not to wash carrots and beets before storage. We store ours washed for two reasons. The first is that my barn is really a three season barn, and is pretty cold in the winter, making washing very uncompfortable. I also have better luck getting them really clean when they are first out of the soil as the soil can stain carrots. If you can keep the humidity high enough, the soil won’t stain the carrots as much, but I just assume get them done in the fall.

Carrots and beets will store until the spring if kept cold enough. Store them in vented plastic bags at 34°F till spring. It is commonly said that you can not store washed carrots longer than 6 or 7 weeks, but we kept ours into the next season, and they did fine. I was super picky about what went into storage, and anything questionable was set aside for earlier use.

For those who bring in carrots and beets and store them dirty, there are a few considerations. First, it is important to make sure that they are cooled quickly. Bringing in tons of unwashed, warm roots can overload the capacity of many walk-in coolers. A local grower I know leaves his bags outside on a cool evening and picks them up in the morning before the sun comes out. This way he is leaving a lot of the field heat outside. The other piece is to stack the bags in a way that allows for air flow around the pile. A heap against a back wall will have a core that takes a long time to cool down, and those roots will degrade quicker. Misting the stacks with water will help keep the humidity up, and make them last longer and be easier to clean.

Cabbage

We have had good luck storing Napa cabbage in the cooler for long stretches as well. They keep at 34-36°F and have had them be beautiful after stripping the outer leaves 5 months after going into the cooler. The same with red and green cabbage. Clean them up before they go into the cooler and keep them cold.

Winter Squash

Winter squash is one of my favorite things. I look forward to it for at least the second half of summer, and enjoy it well into the winter. Curing the squash is important, not only for flavor but also for storage. We use our greenhouse again, keeping them in there for at least two weeks before we bring them to market. I keep them in the greenhouse until late fall, and then move them into a cold room, which we keep around 50°F and a relativehumidity of around 50-60%. I keep checking them, and I eat them as they get a bad spot. They can suffer injury at temperatures below 50 F, so be careful with the temps.

I hope that this season has brought you loads of good food for your families and customers, and that a well deserved rest is on the horizon.