Growing Watermelon

Best Planting Times for Watermelons in Alaska

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingMay 15 – June 1
Transplant OutdoorsJune 15 – June 30
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Watermelon Planting Conditions

Alaska’s distinctive climate is characterized by short growing seasons and cooler temperatures, making watermelon cultivation a unique challenge. The state’s USDA Hardiness Zones range from 2b to 6a, requiring careful management of planting times and conditions.

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Greenhouse Growing

In Alaska, utilizing a greenhouse offers numerous advantages for watermelon cultivation, especially during the brief growing season. A greenhouse provides a controlled environment, allowing for consistent temperatures, protection against harsh weather, and an extended growing season for watermelons.

Consider investing in a 10×12 FT Greenhouse priced at $1,199 to ensure your watermelons thrive in a controlled environment.
Greenhouse Image 1
Greenhouse Image 2
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Fertilizer

For optimal watermelon growth in Alaska, supplementing with fertilizer can ensure abundant and healthy harvests. Quality fertilizer helps replenish nutrients in the soil and promotes vigorous plant growth.
Fertilizer Image
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Plant watermelons outdoors in Alaska approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for Alaska’s Major Cities

CityAverage Last Frost Date
AnchorageMay 14
JuneauMay 8
FairbanksMay 20
WasillaMay 18
KenaiMay 25

Disclaimer: Frost dates are average estimates, and actual conditions may vary. It is recommended to monitor local forecasts and adapt planting decisions accordingly.

Starting Watermelon Indoors

In Alaska (Zone 3b and 4a), begin indoor watermelon seed starting around April 1 to April 15. This timing helps ensure that seedlings are ready for transplantation outdoors by mid to late May, after the last frost has passed.

Transplanting Watermelon Seedlings

Transplant watermelon seedlings outdoors from May 15 to May 31, ensuring that the soil temperature has consistently warmed to at least 70°F. Space the seedlings 24-36 inches apart in rows that are at least 5-6 feet apart to accommodate their sprawling growth.

General Care and Maintenance

Watering

  • Water deeply and consistently to maintain evenly moist soil, especially important in regions of Alaska that may experience variable rainfall.
  • Avoid watering the leaves and focus on the base of the plants to minimize the risk of fungal diseases.

Fertilizing

  • Use a balanced fertilizer at planting and reapply when the first fruits begin to form. Adding organic matter or compost to the soil prior to planting can improve fertility.

Pest and Disease Management

  • Check regularly for pests such as aphids, root maggots, and signs of diseases like powdery mildew. Despite cooler conditions, pest control remains vital.
  • Consider using organic or integrated pest management strategies to keep watermelon plants healthy and productive.

Harvesting

  • Harvest watermelons when they reach the desired size and the tendril closest to the fruit turns brown. Regular harvesting helps encourage further fruit development.

The importance of good soil

Before starting to grow it is important to take a step back and find the condition of the soil in your garden,The optimal soil is a blend that includes the mineral-rich dirt along with organicrich organic matter that plants need to thrive.


In my garden I try to compost as mutch as possible, so I can mix in the nutrient ritch compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you dont have the time or space for composting, it is possible to get compost ready to use in garden centers and Community Composting.
You can read more on Community Composting here: https://www.epa.gov/sustainable-management-food/community-composting

If you are uncertain of the quality of your soil, you can get easy to use soil tests at amazon for 17 dollars. Check latest prices here: Soil testing kit.

Also remember to check out how much sunlight your growing area gets, and that the rain drains well. If you treat your soil well and plan you crops according to your climate you will succeed with any plant you want.

The satisfaction when you harvest your own produce is well worth the time you put in:)

BeeJay
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