How to Grow Watermelon: A Complete Guide for Melons

Written by: Luke Marion

Published on May 15, 2019

Updated on January 2, 2025

Eating sweet, juicy watermelon is an icon of a great summer. These summertime fruits are a hit at barbecues, pool parties, and picnics alike. Not many people know how to grow watermelon successfully, so I am sharing my love for growing melons with you. From learning about different melon types to knowing when and how to plant and how much sun melons need, I've got you covered.

Let's start this tasty adventure together!

Why I Love Growing Melons

Planting a seed and seeing it grow into a big, sprawling plant is magical, but eating my own home-grown melons is the best part. Everyone talks about the great flavor of home-grown tomatoes versus store-bought, but I am telling you that home-grown watermelon is on a whole new level!

My goal is to help you successfully grow and enjoy great produce in your garden too. Here are my favorite growing tips; from my melon patch to yours, so you can have an Autopilot Garden.

I have created this guide to teach you how to grow watermelon and many more like it:

Varieties of Melons

While they are some of the most popular fruits to grow, melons are also some of the most difficult for home gardeners. Melons are divided into three main categories: muskmelons, honeydew, and watermelons.

Muskmelons, of which cantaloupes are a type, have raised netted skins and flesh varying from orange to white. Closely related to muskmelons, honeydews have smooth skin and usually have green flesh.

Watermelons are a different species that originated in tropical Africa. Compared to other vining crops, they are more sensitive to diverse conditions. Whether you grow Crimson Sweet Watermelon, Sugar Baby Watermelon, Tendersweet Orange Watermelon, or a different variety, once you get it dialed in, there is nothing like a good home-grown watermelon.

Watermelons need a long growing season, up to 150 days. Sometimes, here in Michigan, we are lucky to get a mature watermelon ready to harvest by the end of the year.

Unfortunately, melons may not produce well in most northern regions, so before choosing which varieties to try to grow in your area, it is a good idea to look at the “Days to Maturity” on seed packets.

When to Plant Melons

Before learning how to grow watermelon, it’s important to know when to plant. Timing is important when it comes to seed starting. I recommend starting your melon seeds indoors 1 to 2 weeks before the last frost. My Seed Starting Guide can help you get your melon seedlings off to the right start.

Find the estimated last frost date for your area (you can use Clyde’s Garden Planner & Planting Guide) to give melon seedlings time to mature before transplanting them outside.

Warmth is really the key to growing perfect melons. I don't recommend planting them outside until soil temperatures are between 65°F and 70°F. Start hardening off the seedlings seven to ten days before you want them to go into the garden.

How to Plant Melons

When you are ready to plant that sweet, juicy fruit we all love, the soil should be just right, the sun needs to be shining, and there needs to be a lot of space in your garden.

Choose a Location - Melons must be planted in a location that gets full sun (during warm weather only). Pro-Tip: A low garden area where the soil tends to stay damp is a good choice as long as it gets full sun.
Check Soil pH Levels - A slightly acidic soil is recommended. Use a soil test to find if your soil has the best pH for growing melons, which is 6.0 to 6.5.
Amend the Soil - I recommend a basic garden soil amended with sand for drainage and lots of compost. This provides melons with well-drained soil and has lots of aeration for their roots. Pro-Tip: Watermelons and cantaloupe both require very loose soil to grow a large root base. The root base of a melon needs to be able to support the entire plant.
Plant Spacing - Melons tend to be garden hogs! Watermelon vines and fruit take up so much space in the garden that most melons require a 5-foot x 5-foot space. For watermelons, I dedicate at least a 5-foot x 20-foot space! You can plant them closer together when trellising, but I do not recommend trellising large melons that will be over 5 pounds.
Planting Depth - Melons grow best when planted in a mound of soil. Do do this, loosen the soil in a radius around your planting location (about 5 feet in diameter per plant). Then, mound up the loose soil and plant one seedling in the middle of each mound.
Water - Watermelons are about 90% water, which means adequate watering is crucial. Melons are deep-rooted but need consistent moisture. Don’t ever allow the soil to dry out completely and make sure to give them plenty of water right up until its time to harvest watermelons. Pro-Tip: Be prepared to combat powdery mildew because of the damp environment. Use a drip irrigation system or avoid overhead watering late in the day to minimize powdery mildew.

Fertilizing Melons

As you can guess, a 20-pound watermelon requires a lot of nutrients, so fertilization is important. Watermelons are heavy feeders. They need nitrogen to develop strong leaves and stems and phosphorus and potassium to develop flowers and fruit.

Just like when growing zucchini, I like to give watermelons Trifecta+ when I plant them and a minimum of two feedings of blood meal per season.

This provides the plants with a lot of fast-acting Nitrogen for an immediate boost and continuous slow-release Nitrogen later on. The Rapitest Soil Tester kit contains 10 tests each for Nitrogen, Phosphorus, and Potash (plus 10 for pH!) to take the guesswork out of how much fertilizer to add to your soil.

Harvesting Melons

All of the work is worth it when I get to enjoy melons from my local farmers' market (aka my garden). There's nothing like eating a fresh, juicy home-grown watermelon!

Watermelon

But it can be difficult to tell when watermelons are ripe. If you pick them a week too soon, they will be watery and pale. If you pick them a week too late, they will be mealy and mushy.

The first indicator that a watermelon is ripe is by looking at the tendrils. Find the tendrils next to where the fruit is attached to the vine. Dry and brown tendrils indicate mature fruit. It is a sign that the vine is starting to harden the stem and mature the melon.
Another indicator that a watermelon is ripe is the belly. Look for the color of the belly to start to transition. You should see the vibrant green color start spreading even into the belly of the melon. Pro-Tip: The belly of the watermelon is not a certain part but can be any part of the melon. The belly is whichever part of the melon has been touching the soil and doesn’t have access to sunlight.
The last indicator of ripe watermelon is scratching or webbing. Animals will scratch at the ripe watermelon because they want to access the sweet flesh inside. This isn’t a sure-fire way to know, but it is a good clue.

Even when all the signs indicate that a watermelon is ripe, there is still about a 20% chance that it is underripe. Don’t get discouraged if you harvest an underripe melon. We've all done it before! It's simply part of the journey.

Muskmelon

Muskmelons are ready to pick when the fruit pulls easily from the vine.

Some other signs a muskmelon is ready to harvest:

You may also notice cracking around the part of the melon attached to the vine, when these cracks are about 3/4 of the way around, it's ready to pick.
The skin between the netting changes from green to a yellow or tan color.
The texture of the rind becomes slightly rough, and the flower end (opposite the stem) feels slightly soft when pressed.
Finally, check for the sweet melon aroma! If you smell near the stem end of the melon, it should smell like a sweet melon.

Always harvest muskmelons early in the day, after the morning dew has dried.

Honeydew

If you wait until a honeydew slips off the stem, it will be overripe. Here are the key things to look out for to know when your honeydew is ready to harvest:

Keep an eye on the leaves near the stem of the melon. These are often yellow when the honeydew is ripe.
Watch the size - a ripe honeydew will be large and no longer growing in size.
The melon will turn from green to a creamy pale yellow or even white, and the skin will look almost shiny.
The flower end (opposite the stem) feels slightly soft or springy when pressed.

Because honeydew doesn't easily detach from the vine, use a pair of gardening shears to cut the melon from the vine.

Storing Melons

Ideally, melons are best when harvested and sliced into immediately. I know we all enjoy a nice crisp and cold melon, but only netted melons (muskmelons) should be stored below 45ºF, so resist the urge to store them in the refrigerator.

If you're not ready to slice into your melon, store it at room temperature, away from other fruit that may give off ethylene gas (which causes ripening), unless, of course, you're trying to get your melon to ripen a bit more.

With proper storage, many varieties of melons can last 2-4 weeks.

Now that you know how to grow watermelon, it's time to try it! Use all these tips and tricks to grow bigger, juicier, and more flavorful melons this year.

FAQ

How long does it take to grow watermelons from seed?

Watermelons need a long growing season. Some varieties require up to 150 days.

How deep should I plant watermelon seeds?

Mound up the soil and plant watermelon seedlings about twice as deep as the seed is wide in the mound.

What kind of space do I need for watermelon plants?

Watermelon plants need lots of space. I dedicate a minimum 5-foot x 20-foot space per watermelon plant.

How much sun do watermelon plants need?

Watermelon plants need a warm, sunny location with direct sunlight.

What fertilizer is best for growing watermelons?

I have the best results when I use Trifecta+ with at least two feedings of blood meal each growing season.

What are some signs that my watermelons are ripe for harvest?

Check if the tendrils nearest to the fruit are dried up and brown. That is a sign that the fruit is ripe.

Can I grow melons in containers?

Yes, you can! Here is a video on how to grow cantaloupe in containers.

Does the thump test work to determine ripeness?

The sound a melon makes when you thump it has zero bearing on ripeness. What it can tell you is how dry a melon is. A hollow-sounding thud tells you it is a drier melon. A dense-sounding thud means it is a juicy melon.

Once I harvest melons, will they finish ripening on the countertop?

No, once you cut a watermelon from the vine. It is done ripening. A cantaloupe might soften a bit when left on the countertop, but the sugars have already been created. Avoid harvesting too soon for the best-tasting melon.