Every year as the weather warms up again after a long winter all of the gardeners here in the Matsu Valley and all around Alaska rush to get everything planted out in their garden just as early as absolutely possible.
With the return of warm sunny days it is so tempting to set out plants and yet the idea of another killer frost overnight is always in the back of your mind. I took the extra step to purchase a home weather station and tracking overnight low temperatures has saved my bacon several times. I found out that my property can be colder than locations just a few miles away. On May 19th, I recorded an overnight low of 32 degrees. Luckily I took the time, before going to bed, to turn on my small electric space heater in my greenhouse that kept the temperature inside above 40 degrees and protected my sensitive seedlings.
This graph shows a 3 day temperature record from my home weather station. The Green line is the temperature inside my greenhouse and the red line is the temperature outdoors. As you can see, my greenhouse warms up quickly when the sun is shining on my greenhouse and cools down at night. My property is lower than my neighbors and slopes slightly to the northwest. I am also on the edge of a valley. So all of the cold air flows down to the valley overnight and right through my yard. Some years we might have a mild winter with an early Spring warm-up but you need to stick with your usual planting dates. The climate here in Alaska is definitely warming faster than anywhere else, but our average last spring frost date here is still around May 20. When I first moved to this property in 2004, the well known Iditirod Sled Dog Race had their Official Start here in Wasilla, yet around 2010 they had to move 30 miles further north because of our lack of snow. In the past 10 years, they had to move the whole race to Fairbanks twice and change the route completely due to the lack of snow on the traditional trail. So by following my home weather station I might plant some cold tolerant crops, such as kale, lettuce, and onions, out in my garden by mid May, but sensitive seedlings are not planted outdoors until the last Weekend in May.
I use hoop tunnels and IRT plastic mulch to warm up my raised beds for plants that are not cold tolerant. I even tried using water filled jugs to try and store some of the daytime warmth and protect my plants through our springtime cold nights.
I also constructed these wire covered hoop cages to keep the neighborhood moose from destroying my garden, as they regularly did in the past. Installing a permeant moose-proof fence around my garden was just not in my budget. My tomatoes will be planted in my self watering 5 Gal. Alaska Grow Buckets inside my small greenhouse.