Although the growing season in Alaska is short, the near 24-hour sunshine of the summer months will keep vegetables growing around the clock. Many world-record vegetables have been grown in Alaska, like the cabbage that weighed in at a massive 127 pounds at their 2009 state fair. However, with plant hardiness zones ranging from 1 to 7b and wide variations in climate, vegetable gardening in this state is definitely challenging. Starting plants indoors well before the last frost is the best way to extend the growing season.
Decide what vegetables you will grow and purchase good quality seed either locally or by mail. Your local University of Alaska county extension office can provide suggestions on what varieties grow well in your area.
Fill your planting trays with sterile potting mix and add water to moisten. Plant the seeds 1/2 inch apart in narrow rows, keeping each variety of vegetable separate for easy identification. Cover the seeds lightly with potting mix and maintain the room temperature at 70 degrees Fahrenheit. Keep the tray humid by covering with plastic until the seeds have germinated.
Transplant the seedlings as soon as they have grown leaves to another tray filled with sterile potting soil. Space them 2 inches apart. One week before transplanting to the garden, harden off the seedlings by placing the trays outdoors for progressively longer periods each day. Use a cold frame for hardening off if available.
Select a site for your vegetable garden that is well exposed to sunlight. If the ground is sloped, choose a southern exposure if possible. Remove plants, grass and other debris from the garden area and loosen the soil to a depth of 6 inches. Spread 4 to 6 inches of well-aged compost or manure over the area and dig it into the soil. Allow the plot to rest for three to four days before planting.
Rake the plot level and pull the soil into long mounds roughly 6 inches high to form planting rows. Orient the rows north-south to maximize the plants' exposure to sunlight. Smaller vegetables such as onions, lettuce and carrots can be planted in rows spaced 18 inches apart.
Transplant your cool season vegetables first. Peas, onions, lettuce and radishes are examples of cold hardy varieties that can withstand cooler conditions. A local volunteer with the Master Gardener Program coordinated by the University of Alaska Extension Service can provide assistance with planting dates for each type of vegetable.
Irrigate your garden with at least 1 inch of water per week. Direct the water to the soil rather than spraying. This will help to keep the foliage dry, which lessens the chance of insect and disease problems. Weed the garden regularly to minimize competition for soil nutrients.