Growing Watermelon

Watermelon Planting Dates Idaho

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

Planting Conditions

Watermelon Planting Conditions

Idaho’s climate ranges from semi-arid to mountainous, with USDA Hardiness Zones mostly between 4b to 7a. This presents various challenges and opportunities for watermelon cultivation, as the state experiences cold winters and warm summers.

Affiliate Disclosure: As an Amazon Associate, I earn from qualifying purchases at no extra cost to you.

Greenhouse Growing

In Idaho, utilizing a greenhouse provides a controlled environment that enhances watermelon growth by protecting plants from late spring frosts and early fall freezes. With temperature regulation, you can enjoy an extended growing season and better fruit quality.

Consider investing in a 10×12 FT Greenhouse (Right now priced at $889 )to ensure your watermelons thrive in a controlled environment.

Greenhouse Image 1
Greenhouse Image 2

Check the latest price on Amazon.

Seeds

Choosing the right seeds is crucial for effective cultivation. High-quality watermelon seeds contribute to better germination and vigorous growth.
5 pack of different Melon Seeds
Browse Watermelon Seeds on Amazon

Planting Trays

Utilizing planting trays helps keep seedlings organized and ensures ample space for growth before transplanting. This results in healthy plants ready for outdoor conditions.
Planting Trays Image
Find Planting Trays on Amazon

Grow Lights

If natural light is limited, using grow lights can significantly boost plant development by providing young plants the light they need to thrive.
Grow Lights Image
Check out Grow Lights on Amazon

Seed Starting Soil

Opting for light, fine seed starting soil promotes quick root establishment and encourages strong seedling development.
Seed Starting Soil Image
Get Seed Starting Soil on Amazon

Fertilizer

Supplementing with fertilizer can enhance watermelon growth in Idaho, helping to replenish soil nutrients and promoting healthy, robust plants.
Fertilizer Image
Check out Fertilizer on Amazon

Other planting guides for Idaho:

Broccoli Planting in Idaho

Pumpkin Planting in Idaho

Tomato Planting in Idaho

Any questions on growing watermelons? Visit our forum to discuss: Gardening Forum.

Starting Watermelons Indoors

In cities like Boise (Zone 6a), begin indoor watermelon seed starting between March 15 and April 15. This timeline ensures healthy seedlings ready for outdoor transplantation starting from late May to early June once the risk of frost has passed.

Transplanting Watermelon Seedlings

Transplant watermelon seedlings outdoors from May 20 to June 5, ensuring the soil has warmed above 70°F consistently. Space the seedlings 36-48 inches apart in rows with at least 48 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. Idaho’s climate, with its dry spells, necessitates regular watering to prevent soil dryness.
  • Water at the base of plants to avoid leaf wetness, reducing the risk of fungal diseases.

Fertilizing

  • Apply a balanced fertilizer during planting and when the first fruits start forming. Incorporating compost before planting can enhance soil fertility and structure.

Pest and Disease Management

  • Regularly monitor for common pests like aphids, cucumber beetles, and powdery mildew. While Idaho has a varied climate, pest vigilance is essential.
  • Implement organic or integrated pest management methods to protect watermelon plants from pests and diseases.

Harvesting

  • Harvest watermelons when they reach the desired size and color, and the tendrils have dried. Regular harvesting promotes optimal fruit quality.

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
Latest posts by BeeJay (see all)