Even if you have a black thumb, you CAN grow watermelon! In this post, we will teach you how to not kill watermelon. Learn all about the basics that will help you become a successful watermelon gardener, including which varieties are available, how to plant, harvest, and preservation.

And the Winner is… Watermelon!

Did you know that we have a Facebook group called Black Thumb Garden Club with Lauresa and Mariah? It is a great place for club members to ask questions, share ideas, and support each other. Have you joined our group yet? If not, we would love to have you!

I polled our group members about what they wanted to learn about next and the winner was… fruit! So today we are learning about watermelon.

Watermelon is fairly easy to grow, it just requires a longer growing season, so be sure to start those seeds early!

Choosing the Best Watermelon Variety for Your Garden

Did you know that there are literally hundreds of varieties of watermelon? You may have thought that you only had to choose between seeded and seedless, but that is not so!

To make things simple (and really interesting), there are actually five categories of watermelon.

Seeded: These tend to be larger melons that can grow to be up to 45 pounds, but are typically closer to the 15-30 pound range. As the name implies, their main characteristic is that they have a good amount of seeds. Rumor has it that they also have the most flavor.
Seedless: Seedless watermelons are a hybrid and are some of the most common watermelons out there. And while we might think that seedless watermelon consist of one lone variety, quite a few varieties fall into this category. These watermelons are smaller than seeded watermelons, but larger than mini watermelon. They are usually around 15 pounds.
Mini: These watermelons have thin rinds and are the smallest of all the watermelons. They weigh in around 12 pounds and tend to have shorter vines.
Orange/Yellow Fleshed: Yep, not all watermelons are red… there are quite a few that have yellow and orange meat.
Watermelon cousins: Which are not really watermelons, just close relatives. These include cucumbers and squash.

Whatever variety you choose, be sure to choose one that will fit in your space and meet your family’s needs.

This year I am growing a Sugar Baby watermelon. It is a mini watermelon with 3-4 foot vines which is perfect for my raised beds. And a 12 pound melon seems easier for my little family to eat than anything bigger.

How to Grow (aka How Not to Kill) Watermelon

Watermelon seeds do great when planted directly in the ground, but they will also do just fine started indoors (which may be useful if you have a shorter growing season). If you are starting seeds indoors, do so 4-6 weeks before the last frost date for your area.

Plant your seeds or transplants after danger of frost has passed. They will also do better with warmer soil, so most people suggest waiting for a couple of weeks past the last frost date to plant.

Watermelon does best when grown on a hill. If you are direct sowing seeds, you can plant 5-6 per hill and then thin to 1 or 2 once they are a few inches high. When planting using the square foot gardening method, one have one plant for every TWO square feet and make sure that it is planted on the edge of the box to allow the vine to grow outside of the box.

Before there is any fruit growing on the vine, water a lot… 1-2 inches a week is ideal. However, once fruit starts to grow, reduce water to allow the fruit to get sweeter.

You will have better fruit production if you pinch off any side shoot vines that start to grow.

Like other vining plants, you will get male and female flowers. Female flowers have little baby watermelon growing under the flower. If you do not have sufficient bee activity, you may need to do what is called forced pollination.

Forced pollination is quite simple. Want to know more about what plants may require forced pollination and how to do it? We discuss the details in our book The Black Thumb Garden Club Workbook. Check it out!

Once fruit starts to grow, you should do something to keep the fruit from rotting where it rests on the ground. I have some clever little melon cradles that I got for a great price (I got them from Gardener’s Supply) or your can use cardboard or straw.

How (and When) to Harvest Watermelon

By late summer you should have some fruit growing on your vine. You will most likely get 2-4 melons per vine.

Perhaps one of the greatest watermelon mysteries is determining when they are ready to harvest. There are a couple of ways to tell when to harvest.

Watermelon fruit only takes about 2 weeks to mature, so check it regularly. When there is less contrast between the stripes on the rind, gently thump the melon. If it sounds hollow, it is ready to harvest. You can also watch the tendril. Once it starts to dry up, your watermelon is ready.

Cut watermelons off of the vines with a sharp knife close to the fruit.