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Annual Growing Season Summary for the Georgeson Botanical Garden, Tanana Valley, Alaska
The 2012 growing season had frost free season of 104 days, the shortest since 1997. From 2006 to 2011, frost occured in late September, providing a long, warm Indian Summer. Not so this year when frost was severe (25F), cutting short many gardens around the Tanana Valley. The season was cooler than the average thaw-degree day accumulation for the past decade. Growers had few complaints about the season except for it shortness. Wile berry yields throughout the Valley were fair.
Precipitation between May 1 and September 30 was 7.71 inches. Precipitation was below normal in July, August and September, and irrigation was beneficial for most market gardens around the Interior.
The growing season lasted 129 days (last frost May 17 – first frost September 21). The average temperature in May was the second warmest in the past ten years, reaching a high of 81 degrees F on May 28. Temperatures and precipitation in June were close to normal. July temperatures were normal,
The wet weather in July promoted an outbreak of Sclerotinia (cottony rot), which can be a problem in wetter years when no fungicide is applied. The fungus hit the petunias particularly hard, and many were removed from the garden earlyin the season to prevent further spread of the disease. Ornamentals that were not diseased offered beautiful displays throughout the extended season and all vegetable crops grew well. Overall, 2010 offered a long prolific season at the Garden and around much of the Tanana Valley. It was a pretty good wild blueberry year in the Valley
Although the 2009 season seemed quite warm, it was only the fifth warmest since 1999 (based on thaw degree days). However, The growing season of 126 days was 11 days longer than the 30-year mean. May started with a record high of 76°F and was warmer than normal. June was about average while July had the highest average daily maximum temperature and the lowest precipitation ever recorded in Fairbanks. The high temperatures combined with the drought enhanced area wildfires resulting in heavy smoke in the area for much of the latter half of July. August had cooler temperatures and increased rainfall which alleviated wildfire threats. September’s mean temperatures were about 4° above the long term mean.
The good weather was not without its drawbacks for both people (smoke) and plants (pests). The warmer than usual weather in May and July promoted a population explosion among insect pests, and aphids in particular decimated eggplants, pepper, and delphiniums.
Voles were a major problem throughout the Interior, and they caused more damage in the garden than we have seen in 30 years. The entire pea crop was destroyed along with some peppers, artichokes, herbs and several annual flower bedding plants that were devoured in flats before they had a chance to be planted. Despite a healthy population of least weasels in the garden, the voles outnumbered them in this warm season.
The last spring frost was 24 May (31°F, -0.6°C). Thaw degree-day accumulation was below the previous ten-year average of 3318.9 degree-days. The frost-free season was two days longer than the previous ten-year average. More than half of the summer precipitation occurred in July, but there were no adverse eﬀects on vegetable growth. The weather statistics describe a fairly typical growing season for Fairbanks.
Most cultivars grew well, and harvest dates were typical for the Fairbanks area. Fall frost occurred on 13 September and did not inﬂuence the major harvest season for most vegetables. Temperatures dropped to 23.1°F (-5°C) on that date. Soils froze 1–2 inches and remained frozen for several days. Many local growers lost potatoes to freeze damage following vine removal because of the severity of the frost.