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Growing watermelon in Missouri is totally doable when you work with the state’s climate instead of fighting it.
Missouri sits in a sweet spot where summers get hot enough for watermelons to thrive, but the growing season isn’t as long as places further south.
If you’ve ever wondered how to grow watermelon in Missouri, the short answer is to pick the right variety, plant after the last frost, and give those vines plenty of sun and space.
In this post, we’ll walk through how to grow watermelon in Missouri step by step, from choosing seeds to knowing when to harvest.
Let’s dig in.
How to Grow Watermelon in Missouri: The Basics
Growing watermelon in Missouri starts with understanding your local climate.
Missouri falls in USDA hardiness zones 5b through 7a, which means winters can get cold and the last frost usually happens between mid-April and early May.
Watermelons are warm-season crops that need soil temperatures of at least 70°F to germinate and thrive.
That’s why timing is everything when you grow watermelon in Missouri.
If you plant too early, cold soil will stunt or kill your seedlings.
If you plant too late, your watermelons may not have enough time to ripen before the first fall frost.
The key is to start seeds indoors about three to four weeks before the last expected frost date in your part of Missouri.
Then transplant them outside once the soil has warmed up and nighttime temperatures stay above 50°F.
You can also direct sow watermelon seeds in Missouri once the soil is consistently warm, usually by mid-to-late May.
Either way, growing watermelon in Missouri requires patience and a watchful eye on the weather.
Choosing the Right Watermelon Varieties for Missouri
Not all watermelons are created equal, especially when you’re growing them in Missouri.
Because Missouri’s growing season is shorter than in states like Georgia or Texas, you’ll want varieties that mature quickly.
Look for watermelons that ripen in 70 to 85 days.
Here are some great picks for growing watermelon in Missouri:
1. Sugar Baby
Sugar Baby is a classic icebox watermelon that matures in about 75 days.
It produces small, round fruits with sweet red flesh, perfect for Missouri’s shorter season.
2. Crimson Sweet
Crimson Sweet is another reliable choice for growing watermelon in Missouri.
It matures in around 85 days and produces large, striped fruit with crisp, sugary flesh.
3. Black Diamond
Black Diamond is a dark-skinned heirloom that takes about 90 days to mature.
It’s a bit slower, but if you start early indoors, it can work well in southern Missouri.
4. Jubilee
Jubilee is a heat-loving variety that does well in Missouri’s hot, humid summers.
It matures in about 85 days and produces large, oblong watermelons with bright red flesh.
Planting and Caring for Watermelon in Missouri
Once you’ve picked your varieties, it’s time to get planting.
Watermelons need full sun, at least eight hours a day, and well-drained soil rich in organic matter.
If your Missouri soil is heavy clay, amend it with compost or aged manure to improve drainage.
Plant your watermelons in hills or mounds about three to four feet apart, with rows spaced six to eight feet apart.
This gives the vines plenty of room to sprawl, which they love to do.
Water deeply once a week, aiming for about an inch of water per week.
Avoid overhead watering if you can, since wet leaves can invite fungal diseases, which are common in Missouri’s humid summers.
Mulching around your plants helps retain moisture and keeps weeds down.
As your watermelons grow, you may need to hand-pollinate if bees are scarce, but usually, nature takes care of it.
Watch for pests like cucumber beetles and squash bugs, and treat them early with insecticidal soap or row covers.
When to Harvest Watermelon in Missouri
Harvesting watermelon in Missouri usually happens from late July through September, depending on when you planted.
How do you know when a watermelon is ready?
Look for these signs:
1. The Tendril Trick
Check the tendril closest to the fruit.
When it turns brown and dry, the watermelon is ripe.
2. The Thump Test
Give the watermelon a good thump.
A ripe melon sounds hollow and deep, while an unripe one sounds dull.
3. The Ground Spot
Flip the watermelon over.
A creamy yellow spot means it’s ready, while a white or green spot means it needs more time.
So, How to Grow Watermelon in Missouri?
Growing watermelon in Missouri is absolutely possible when you choose fast-maturing varieties, plant after the last frost, and give your vines plenty of sun, water, and space.
The key is to work with Missouri’s climate by starting seeds indoors, amending your soil, and keeping an eye out for pests and diseases.
With a little patience and care, you’ll be harvesting sweet, juicy watermelons from your own Missouri garden before you know it.
So go ahead and give it a try.
You might just grow the best watermelon you’ve ever tasted.