By Julie Riley, Cooperative Extension Service
Bite into a vine-ripened tomato and you know your gardening efforts this summer have been worth it. The key phrase here is vine-ripened. If you have tomatoes starting to turn red, do whatever it takes to encourage the fruit to fully ripen before picking. A big reason we garden is for the flavor that home-grown varieties bring if grown and harvested properly.
Tomatoes ripen in response to a host of factors but temperature plays a critical role. Your strategy at this time of year is to encourage plants to accumulate more heat units and be prepared for early frost. Soon the fuss won’t be worth it. University of Alaska Fairbanks horticulture professor Meriam Karlsson said harvesting ripe tomatoes not grown in a greenhouse all depends on the weather during the last two weeks of August.
Try to get at least a few fruit to ripen on the vine. If you’re growing tomatoes outside, build a plastic enclosure to collect the sun’s rays. In the evening, cover plants with row cover and add a little heat with a low-watt light bulb. If you’re a container gardener, put the pot on wheels and move it inside at night.
Ripening is a complex process. Grocery-store tomatoes taste bland because most are picked green and stored cool before ripening at 68 degrees. Tomatoes that are green turn a mature green before starting to show a bit of red or orange. Mature green is a color you can see. It’s lighter, more translucent. Unfortunately, chilling injury can occur on green fruit when temperatures drop to 50 degrees and damage can be even heavier on those exposed to colder temperatures. On the bright side, red tomatoes that are not fully ripe are able to tolerate colder temperatures better than those that are green.
I have been waiting and waiting for my 3-inch Polar Beauty tomatoes to ripen. I have practically been salivating in anticipation of their vine-ripened flavor after seeing beautiful red Polar Beauty tomatoes at the Tanana Valley Fair.
To understand where I’m coming from, you need to know that I grew up in Wisconsin where tomatoes grow like weeds. When I started my job with the UAF Cooperative Extension Service, it was the third week in August. Frost killed the tomatoes a few days later. When I realized that I wasn’t going to get a vine-ripened tomato, I asked for a care package. The frugal man that was my husband mailed me vine-ripened tomatoes from Wisconsin via parcel post. They were soup when they arrived.
The best tasting tomato I have ever eaten in Alaska is a Polar Baby, bred by the late John Holm of Fairbanks. I have great admiration for the few plant breeders who have toiled to provide us with varieties that grow in our cool climate. Holm also developed Polar Beauty and Sub-Arctic 25, the standard by which all other of our outdoor tomatoes seem to be judged. The story of his breeding work is chronicled by Ann Roberts in her book, “Alaska Gardening Guide.”
The only tomato ever released by the UAF Agricultural and Forestry Experiment Station was Early Tanana. This early-ripening tomato was developed by Arvo Kallio in 1970. Early Tanana remains on Cooperative Extension Service’s recommended variety lists but I’m not sure this tomato is worth eating. I don’t like its tough skin. The fruit of Sub-Arctic 25 is small but overall, much more productive. In my opinion, Glacier is better tasting. This cool climate variety will ripen in Fairbanks during warm summers. In three years of trialing eight tomato varieties at the Georgeson Botanical Garden, Prairie Fire and Northern Delight were among the top three yielding varieties. Meriam Karlsson suggests trying Polbig and tomatoes developed at the Beaverlodge Research Farm in Alberta.
Caption: If you are a container gardener, extend the growing season by putting the pot on wheels and rolling it inside at night once the temperatures get cooler.
If none of your tomatoes are candidates for ripening on the vine, by all means harvest those that are a mature green. Tomatoes ripened on the kitchen counter have potential to develop a decent flavor. If you don’t want to wait for ripening, Cooperative Extension Service’s publication, “A Harvest of Green Tomatoes,” offers a great selection of recipes. It is available online at http://bit.ly/ak-green-tomatoes or at Extension offices. Perhaps making green tomato pie will become a fall tradition.
Julie Riley is the horticulture agent for the University of Alaska Fairbanks Cooperative Extension Service in the Tanana District Office. She can be reached at (907)474-2423 or firstname.lastname@example.org