Today, we are going to tell you how to grow watermelons in containers so you can harvest the fresh fruit right from your patio. Let’s go!
How to Start Watermelons
Watermelons may not be the easiest crop to grow, but the taste of a vine-ripened watermelon that’s homegrown is far superior to anything you can get in the store. So sweet, so delicious, and they come in a bunch of different colors. If it’s your first time growing watermelons and you’re growing them in containers, I suggest you plant some small early ripening varieties. A variety like the early moonbeam is a great choice and also the silver yamato.
I would suggest that you kind of stay away from growing some large long season varieties like the alibaba watermelon. This is a great watermelon, but it’s huge and it takes a long time to grow.
Preparing Containers
What I like to do is start my seeds indoors in large cells about two to four weeks before transplanting out. Using a heat mat will help speed up germination. They like the soil temperatures to be between 70 and 95 degrees Fahrenheit. In optimal conditions, they will only take about four to ten days to sprout, or you can directly sow your watermelon seeds right into the containers.
For my containers, I like to use these food safe five gallon buckets. Drill drainage holes at the bottom with a half inch drill bit. They need to be able to drain so the soil does not go anaerobic, which means without oxygen.
Soil & Fertilizer
For soil, you can use a high quality potting mix like a happy frog. This is my favorite, but what I like to do is make my own soil with coco coir, compost, perlite, and vermiculite. Once your young seedlings have two true leaves, they’re ready to be transplanted out. Before that, I suggest you mix in some all-purpose fertilizer into your soil because melons are heavy feeders and they will need the added nutrition. Melon seedlings do not do well if they get root bound, so try your best to avoid that. Also, if the young seedlings get chilled, they may not set fruit. So be patient. It’s always better to plant a bit late rather than too early when it comes to watermelons. Melons like a soil that remains consistently moist but not soggy.
Mulching
Using a mulch is a great idea. It will retain moisture and will keep the soil from heating up too much in the summer heat. As the plants start to vine, Cover them with a diced up leaf mulch and it works great.
Ideal Planting Location
Watermelons need a spot that gets full sun and has good air circulation to help them dry out quickly after a rain to prevent disease. I suggest growing them up a trellis. This will allow for good airflow and they will have less issues because the vines won’t be sprawling on the ground. To tie up the vines, I like to use tomato clips. They’re convenient and easy to use. They make the whole trellising process simple and quick.
Pruning & Additional Fertilizing
After the vines have flowered and small melons are forming, prune the vine a little bit. This way the plant can focus on the production of a few melons that will finish and ripen rather than having a lot of extra growth and a bunch of melons that will never ripen. If you leave all the melons on the vine, most will grow to about the size of an egg and then shrivel and die. It’s better to get a few good melons rather than having a bunch of melons that never reach maturity. When your melons set fruit, you should top dress them with some additional fertilizer. What I like to do is pull back the leaf mulch, then mix in some all-purpose fertilizer into a potting mix or my homemade soil. Then place this in the bucket and mix it into the top few inches. Then water it in. This will make sure the vines have enough nutrition to form the melons.
After your few chosen melons have formed and are growing, as the summer goes on, you want to stay on top of removing some of the new flowers and the small fruit. We want our melon plant to focus on the production and also the ripening of the few chosen melons that we have growing.
Supporting Watermelons

When your melons start to get a bit larger, make sure to give them the support they need on the trellis. I like to cut up a piece of insect netting and use this to make a little sling for them that I tie up on the fence. This will support the fruit and help keep its round shape. And the insect netting is also breathable at the bottom. Bird netting or something similar would work as well. As your melons continue to grow, keep an eye on them. When you see the stem of the fruit starting to lose some color, that’s a good indication that they’re starting to ripen.
Harvesting Watermelons
Picking a perfectly ripe watermelon is not an easy thing. Some people say to thump on the watermelon. If it makes a ringing sound then it’s still green and if it makes a dull or dead sound then it’s ripe. But it will also make a dull or dead sound if it’s over ripe. Other people will suggest keeping an eye on the tendril or pigtail curl right next to where the fruit is. When that turns brown you could harvest.
The thing is that sometimes happens for some varieties about a week before they’re ripe. Another thing you can do is check the underside of your melon. When that goes from like a white color to a dark rich yellow or gold you can harvest. Ultimately picking a perfectly ripe watermelon is not easy. Use all the signs that I shared with you and a little intuition and you’ll be able to pick some perfectly ripe watermelons. This is the silver yamato, an old Japanese variety. So let’s grab this one here, cut it open. First let’s harvest it.
Common Issues & Protection
There’s a few common issues when growing watermelons. One is the cucumber beetle, which spreads bacterial wilt as they feed. A good way to protect your plants from this is by using something as simple as an insect netting. You keep this on your plants and then as they start to flower, you remove it so they can get pollinated. Another great way to protect your plants is using the surrounding kaolin clay. It works great on your young watermelon plants. That will protect them and it’ll make them less desirable for the cucumber beetles to go after.
Another issue is the vine borer, but those two forms of protection are great for the vine borers also. It would be hard to come out and spray the vine borers or the cucumber beetles and get them at just the right time to kind of remove them, but protecting your vines is the way to go.
Final Thought
Overall, growing watermelons in containers is not only a lot of fun, but it works fantastic. There’s so many added benefits that even come from just growing in containers. For instance, you don’t have to deal with some of those soil borne diseases that could happen in the ground when you make your own soil or use a potting mix. So, you think not having enough space to grow some watermelons in the ground is a bad thing, but growing in containers, it’s, it’s awesome. I love doing it. I’m going to be planting a bunch more watermelons this year in containers and then just kind of line some of my fences with them because there’s nothing like eating those fresh, delicious, delicious, juicy watermelons, a true taste of summer.
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