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How to Grow Watermelon: 7 Tips for Growing Watermelon

How to grow watermelon vertically

Learn how to grow watermelon and add this favorite summertime treat to your garden. Homegrown watermelon picked at the peak of sweetness tastes so much better than one bought at the store.  

Watermelon needs plenty of space and at least 80 days of warm temperatures to grow well. If you have both, learn how to grow watermelon with these tips.

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7 Tips for How to Grow Watermelon

How to Grow Watermelon: 7 Tips for Growing Watermelon

1. Select the best variety of quality seeds for your climate and location

In warm climates, most varieties do well. Some favorites include Crimson Sweet and Moon and Stars.

In hot summer climates like the low desert of Arizona, choose short-season varieties or types adapted to the heat of the summer such as Desert King and Hopi Yellow.

In cooler climates, choose short-season varieties such as Golden Midget and Sugar Baby.

Smaller growing space? Choose shorter-vining varieties such as Mini-LoveBush Sugar Baby or Cal Sweet Bush

How to Grow Watermelon: 7 Tips for Growing Watermelon
Mini-Love Watermelon
How to Grow Watermelon: 7 Tips for Growing Watermelon
Hopi Yellow Watermelon

2. Choose and prepare a good location for planting watermelon

  • Watermelon needs plenty of room. Some vines reach up to 20 feet or more. Give watermelon the space it needs to grow well. 
  • Amend the planting area with compost and aged manure. Add a balanced organic fertilizer before planting.
  • Choose a location that gets plenty of sunlight
How to Grow Watermelon: 7 Tips for Growing Watermelon

3. Plant watermelon seeds directly in warm soil

Watermelon does best when directly sown once soil temperatures reach 70℉. Plant outside 2-3 weeks after your last frost date. Sow 3-4 seeds 1 inch deep, 4-5 feet apart. Water well with seaweed emulsion after planting. Thin to the strongest plant when plants have 3-4 leaves. 

If using square foot gardening, plant shorter bush varieties, plant at the end or corner of a bed and plan on one plant per 2-3 squares. 

The best time to plant in the low desert of Arizona is from February 15th through March.  

In cooler climates, start seeds indoors in 4 inch or larger pots 1 month before planting outside. Watermelon is very frost tender; wait to plant if there is any danger of frost.

How to Grow Watermelon: 7 Tips for Growing Watermelon

4. Water watermelon correctly for the best tasting watermelon

  • Water slowly and deeply to allow watermelon roots to grow deep. 
  • Don’t get leaves wet. Wet leaves encourage diseases such as powdery mildew
  • As watermelon nears ripening, cut back on water to encourage sweetness.
How to Grow Watermelon: 7 Tips for Growing Watermelon

5. Feed watermelon throughout the growing season

How to Grow Watermelon: 7 Tips for Growing Watermelon

6. Mulch the plant and protect the fruit

How to Grow Watermelon: 7 Tips for Growing Watermelon

Mulch plants well to prevent weeds and conserve moisture

Once fruit is set, use cardboard or a melon cradle to lift fruit off ground to protect from pests and diseases. 

Growing watermelon vertically? Use melon hammocks to support growing fruit. I use zip ties to attach the melon hammock to the trellis.

7. Harvest at the right time

Knowing when a watermelon is ripe is often the most challenging part of growing them. Here are a few things to look for: 

  • Three tendrils along the stem (going back to the root) end are brown, dry, hard, and curled.
  • The underside of the watermelon turns creamy yellow or white.
  • Low-pitched thump when you hit it lightly – practice thumping unripe melons to hear the difference.
  • Sheen of watermelon changes from slick to dull looking.
How to tell when watermelon is ripe

Comment below if you have questions about how to grow watermelon, or share tips and varieties of watermelon you’ve tried and enjoyed.

How to Grow Watermelon: 7 Tips for Growing Watermelon
How to Grow Watermelon: 7 Tips for Growing Watermelon

Frankie

Saturday 1st of October 2022

hey! My watermelon has been growing and producing all summer and is still going, however I want to switch over to a fall garden. How long can the melons continue to grow? I am located in the Phoenix area?

Angela Judd

Sunday 2nd of October 2022

As temperatures, cool production will slow down quickly. It's up to you if you want to keep it going until then. Always a juggling act to make room for the cool-season crops. Congrats on a successful watermelon season.

Quinlan Ammons

Friday 8th of July 2022

Hi there! I saw on a comment below somebody said one of their watermelons was squishy. You said this may be an indication of rotting. I have a smaller crimson that started getting squishy and really dark towards the area where the flower was. Do you have any idea what this could be? I already pulled it from the garden. I am noticing that the leaves around are getting little brown spots on them that dry up and flake away easy

I have absolutely fallen in love with your page and I’ve been able to keep my garden alive because of you! Thank you so much for all of your knowledge!

Angela Judd

Saturday 9th of July 2022

Hi - could be some kind of rot or leaf-spot. Discard fruit and affected leaves. Check your watering and drainage. So glad the information has been helpful. Best of luck to you!

William

Thursday 7th of July 2022

I live in Avondale, AZ and I have had my watermelon plans in the ground for over 2 months now and it has not produced any fruit. What could be the reasons?

Angela Judd

Saturday 9th of July 2022

If the plant is healthy and growing well, my guess would be the fruits aren't getting pollinated. Try hand-pollination.

Susan

Tuesday 15th of March 2022

Hi Angela - I'm in the far NW valley and have a couple questions...do I need to allow for up to 20 feet of free soil space to grow watermelon (i.e. do the runners need good soil to root in?) And, when watering (and fertilizing (later on), do I water just the area around the initial planting or all the soil where the vines spread? And if planting in ground, how deep does the soil need to be loosened and amended for watermelon?

Angela Judd

Tuesday 15th of March 2022

Hi Susan. No it does not need 20 feet of free soil space, mine often trails off my beds and into pathways, etc. The soil should be loose to a depth of 12-18 inches, water the rootzone of the plant, typically within a few feet of the plant.

Ian B. Walker

Saturday 24th of July 2021

Trim or leave decaying flowers on developing fruits?

Angela Judd

Monday 26th of July 2021

The flowers usually fall off on their own. I would leave them.