How To Grow Watermelon: The Ultimate Guide To Summer’s Bounty

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When you think of Africa or Egypt, do you think of watermelons? Because about 5000 years ago, people in the Kalahari desert in Africa knew how to grow watermelon vines. And you can learn, too!

Sweet, juicy, and full of flavor, watermelon is most commonly associated with the summer months, vacations, picnics, and holidays. People enjoy it in both sweet and savory applications, as food or as a drink. It’s easy to see why they’re so popular!

They’re also surprisingly easy to grow, although they take space. Let’s entangle ourselves in how to grow watermelon vines in your yard so that you can enjoy this sweet and wonderful fruit all summer long!

Good Products While Growing Watermelon

Watermelon: Quick Care Guide

How To Grow Watermelon
A watermelon surrounded by its vine. Source: Lorianne DiSabato
Common Name Watermelon (plus a bunch of individual variety names)
Scientific Name Citrullus lanatus
Germination Time 14 days
Days to Harvest 70-100 depending on variety
Light Full sun
Water 1” per week in mild weather, 2” in hot
Temperature 70-90 degrees during the day optimal
Humidity Tolerates humidity but may develop mildew
Soil Loamy, well-draining soil w/lots of compost
Fertilizer High N for plant growth, then switch to high P-K for blooming/fruit set
Pests Cucumber beetles, squash bugs, squash vine borers, aphids, spider mites
Diseases Fusarium (especially wilts), anthracnose, downy mildew, powdery mildew, alternaria, curly top

Recommended Watermelon Varieties

Did you know that a watermelon is technically a form of extremely large berry? Citrullus lanatus, the watermelon vine, produces what are called “pepo” – a berry with a hard outer skin and no internal divisions in the flesh. Cucumbers are also considered extremely large berries!

Citrullus lanatus is part of the Cucurbitaceae family of plants, a grouping which includes cucumbers, squash, pumpkins, zucchini, gourds, and many melons like watermelon, cantaloupe, and honeydew.

There are quite a lot of varieties of watermelon at this point. Some have been bred over time to produce smaller fruit, where others are gigantic. The largest watermelon grown was well over 200 pounds and was massive in size!

Let’s go over some of the different types of watermelon which are commonly available today and a bit of information about each one.

A Note About Seedless Melons

Seedless watermelon
A seedless watermelon. Source: stevendepolo

When you go to the supermarket, the majority of the watermelons you’re likely to find for sale are seedless varieties. And when you’re learning how to grow watermelon, it may come as a surprise that seedless watermelons are not actually seedless!

While most heirloom varieties produce thick brown or black watermelon seeds, a seedless watermelon actually makes a thin, white or cream-colored seed. In standard varieties, a white seed would be one which has not fully developed yet. For seedless, that’s what they’ll all look like!

Seedless melons have a lower germination rate than seeded watermelons do, and you may need to plant more seeds when trying to germinate them. However, the seeds themselves are easily digestible and not as woody as those of their heirloom counterparts.

I’m going to be including seedless watermelon types in the categories below, but will mark them as seedless with an (S) after the name. That way, you can look for the specific size of melon that you’d like to grow as well as the seed type.

Common Watermelons

Crimson Sweet watermelon
A Crimson Sweet watermelon on the vine. Source: FarOutFlora

This is the traditional watermelon we all know and love. Sometimes gigantic, these melons are available in both seeded and seedless varieties, and can be anywhere from 10 pounds all the way up to massive 200-pounders! These typically have a thicker rind suitable for pickling.

Variety Growing Time Description Where To Buy
Blacktail Mountain 80 days If your nighttime temperatures are in the 40’s, you can still grow these 14lb melons! Good in all growing zones. Buy Seeds
Crimson Sweet 85 days A popular variety that produces 1-2 round fruits per plant that weigh 15-25lbs each. Nicely-striped rind. Buy Seeds
Charleston Gray 85 days Greyish-green outer rind, resistant to fusarium and anthracnose. 28-35lb fruit size. Buy Seeds
Farmers Wonderful (S) 85 days Round, 14-16lb fruits with pink flesh. An average of 1-2 fruits per plant. Buy Seeds
AU Producer 85 days Blocky but round fruit, averaging 25-30lbs. Travels and stores well. Disease-resistant. Buy Seeds
Kleckley’s Sweet 85 days 1887 heirloom variety. Extremely sweet, 25-40lb melons. Thin rind, red flesh. Buy Seeds
Legacy 85 days Extremely sweet, 25-35lb fruits. Bright green stripes on a dark green rind, firm pink-red flesh. Buy Seeds
Sangria 87 days Resistant to some diseases. Produces oval 20-25lb fruit that’s high in sugar content and eating quality. Buy Seeds
Cal Sweet 90 days Dark red flesh, dark green striped rind. Produces 30-35lb blocky long melons. Leaves protect the fruit from sunburn well. Buy Seeds
Congo 90 days Extremely tough rind on 30-40lb melons. Deep red flesh and a high sugar content. Somewhat drought-tolerant for watermelon. Buy Seeds
Georgia Rattlesnake 90 days Also called “Gypsy”. Southern US heirloom favorite grown since the 1830’s. Buy Seeds
Harvest Moon (S) 90 days Sweet pink flesh hiding under a green rind with yellow speckles. Average size of 8-13lbs. Buy Seeds
Moon & Stars 95 days 20-50lbs, distinctive green rind with yellow mottling, heirloom 1924 variety. May have different colors of flesh ranging from red to yellow. Buy Seeds
Carolina Cross 180 100 days Heirloom variety that produces massive melons, often hitting weights over 200 lbs! Buy Seeds

Icebox Watermelons

Sugar Baby watermelon
Sugar Baby watermelons. Source: Suzies Farm

The icebox watermelon is sometimes considered a personal watermelon or baby melon size. These range in the 2-12 pound range, and are usually much smaller in size. They can be incredibly sweet and often have a shorter season. Thinner rinds are common for these.

Variety Growing Time Description Where To Buy
Little Baby Flower 70 days Personal-size watermelon with an average weight of 2-4lbs. Pink flesh, bright stripes. Buy Seeds
Little Darling 70 days Hybrid. Nice oval mini-melon at 5-7lbs, extremely sweet, with vines that spread 4-5′. Nice small size icebox melon. Buy Seeds
Mini Love 70 days 7-9lb melons with deep red flesh, very thin rind that’s split-resistant, very compact plants. Some disease resistance. Buy Seeds
Starlight 75 days 8″ round fruits up to 10-12lbs, pink flesh. Nice festival type. Buy Seeds
Bush Sugar Baby 80 days Compact vines, but not a compact melon. Each plant produces about 2 12lb melons in a small space. Buy Seeds
Sorbet (S) 80 days A nice red-fleshed, 6-8lb round melon with excellent flavor. Slender dark green stripes on medium green rind. Good disease resistance. Buy Seeds
Sugar Pot 82 days Patio-friendly and compact, perfect container watermelon. However, it produces an 8-10lb fruit, and container types just usually can’t. Buy Seeds
Mini Piccolo 83 days 4lb tiny round melons make a perfect personal-size. Each plant can produce up to 6 fruits. Buy Seeds
Red Ruby (S) 85 days Hybrid. Perfect ruby-red flesh on a 6-8lb average fruit. Good size for refrigeration. Buy Seeds
Hime Kansen 95 days Japanese hybrid. Average fruit size is 5-6lbs and extremely sweet. Best if grown with a single fruit to each vine. Thin rind. Buy Seeds

Differently-Colored Watermelons

Early Moonbeam watermelon
Early Moonbeam watermelon slices. Source: karen_hine

Red or pink watermelon flesh is what most people immediately think of, but did you know that watermelons come in yellow or orange-fleshed varieties? Here’s a selection of watermelons in different colors which are equally as flavorful to their red and green relatives.

Variety Growing Time Description Where To Buy
Golden Midget 70 days Miniature watermelon with a golden rind and salmon-colored pink flesh. Extremely early, 3lbs average weight. Buy Seeds
Kaho 75 days Pinkish-orange flesh, extremely thin rind. Long, oval fruits in the 2-4lb range. Japanese variety. Buy Seeds
Sunshine 75 days Nice icebox-sized yellow-flesh melon. Very sweet and juicy, compact vine. Averages 8-10lbs. Buy Seeds
Sorbet Swirl 77 days The flesh of this melon is pastel pink and yellow swirled, average weight of 10lbs. Nice early season melon, performs well in both cool and warm years. Buy Seeds
Cream of Saskatchewan 80 days Cream-colored flesh, 8-10lbs in size, striped green rind. Old heirloom variety. Buy Seeds
Early Moonbeam 80 days Cool-climate melon, 5-8lb fruits with thin rinds and light-green skin with dark green streaks. Bright yellow flesh. Very sweet. Buy Seeds
Janosik 80 days Yellow-fleshed oblong fruit, up to 10lbs size, extra-sweet taste. Really dark green rind. Buy Seeds
New Orchid 80 days Sherbet-like taste, 7-9lb icebox size. Oval-round shape, plants produce 1-2 fruits each. Buy Seeds
New Queen 80 days Very few seeds, a 12% sugar content, and rich orange flesh make these 5-6lb mini-melons a winner. Buy Seeds
Orange Crunch 80 days Melons up to 30lbs! Orange to yellow flesh, sweet and crisp, very few seeds. Average fruit size 20lbs. Buy Seeds
White Wonder 80 days Snow-white flesh, unusual flavor. 3-8lb icebox fruits. Cracks easily so it doesn’t store well, but great for immediate eating. Buy Seeds
Amarillo (S) 82 days Medium-green rind with slender dark green stripes, bright yellow flesh. Roughly 15lb fruits, 1-2 per plant. Buy Seeds
Cream Fleshed Suika 85 days Japanese variety, 6-12lb icebox melons with cream-colored flesh. Light green thin rind with dark stripes. Buy Seeds
Desert King 85 days Pea-green rind, sunburn-resistant, with sweet yellow flesh. 20lb average weight. Extremely drought-resistant. Good for storage. Buy Seeds
Orange Crisp (S) 90 days Big seedless melons with astonishingly orange flesh and a 17-19lb weight. Dark green rinds. Buy Seeds
Orange Tendersweet 90 days Heirloom orange-fleshed melon, oblong fruits up to 35lbs. Very sweet. Buy Seeds
Colorado Preserving 90 days Firm white flesh, not good for fresh eating but popular for candying or preserving purposes. They last for months and are rock-hard. 10lb fruit. Buy Seeds
Mountain Sweet 100 days Popular in the 1840’s on the eastern US coast. Large 20-35lb striped fruit with deep yellow flesh. Buy Seeds

How To Grow Watermelon From Seed

Watermelon vines growing
Watermelon vine and flower with young melon forming. Source: 305 Seahill

Seed is the best way to start for healthy vines, so let’s discuss everything you need to know about planting watermelon seeds!

When To Plant Watermelon

Most watermelon varieties require at least three months of warm conditions to grow. For some of us, that means planting in the spring is just fine. Others may find that right now, at the beginning of summer, is their best bet for great fruit harvests.

I personally prefer to jump-start my seeds indoors prior to planting. You will need soil temperatures of at least 70 degrees (and preferably 80), so you may want to use a heat mat if you’re starting them in the cooler spring months.

Once you’ve hardened off the plant, you can get it in the ground when it’s warmed up. Mid to late May is a popular time for west coast folks, but on the east coast, June to July works quite well too.

Where To Plant Watermelon

Watermelon flower
Watermelon flower. Source: Rosa Say

This is a constant problem for many adventurous gardeners, because many heirloom watermelon vines can reach lengths of up to 20 feet.

You can train watermelons, particularly smaller varieties, to grow on an angled or vertical trellis. However, many people prefer a large available space so their melons can spread, preferably one where kids and pets won’t trample the vines and young fruit.

One option that many people try out is growing the melons directly in the middle of a lawn. You can make a pile of compost in the center of an otherwise-unused lawn space and plant them right there. The vines will spread out and slowly cover the lawn.

If you are a raised-bed gardener, you can still grow them with some pre-planning. You’ll likely want to pick a plant which has a bushing or miniature habit rather than one with rambling vines. Alternately, you can trellis-train them to keep them in a smaller space.

Did you know that it’s possible to grow watermelon in containers, too? You’ll want at least a five-gallon container so the plant has enough root space, but you can teach your watermelon to climb upward!

However you choose to grow your watermelon, be sure it has full sun. While your plants may accept a little shade, especially on the tips of creeping vines, they perform best in full sun conditions. This is not a plant to tuck along the shady side of your house.

How To Plant Watermelon

If you’re starting plants indoors, use 3-4″ coconut coir or peat pots. Larger watermelon vines transplant poorly, so you’ll want to plant these outdoors while they’re still young without disturbing the roots too much.

Use a well-draining potting soil in the pots, and plant 3 seeds per pot at least 1/2″ beneath the soil’s surface. Keep the soil temperature at a minimum of 70 degrees until the seeds germinate. Once the plants have germinated, keep the healthiest sprout and remove the others.

Starting from seed outside? Make a hill of well-draining soil that’s rich in compost, and plant 8-10 seeds per hill at a depth of 1″ below the soil surface. If you’re going to allow your plants to spread out, space these seeds in clusters of 2-3 around the hill. Hills should be 4′ apart.

Once your plants have germinated, select the strongest three plants per hill to save. If you’re going to trellis them, you might want to have only one plant per hill, but you can place hills about 1.5 to 2 feet apart.

We’ll cover how to transplant young watermelon plants a little further on!

Caring For Watermelon Vines

Watermelon field
Watermelon vines in a commercial field. Source: Ahmad Fuad Morad

As much as we’d like to think otherwise, watermelons won’t just miraculously appear overnight… and even if they did, they might not be as tasty as those grown in optimal conditions. So let’s discuss how to grow watermelon in optimal conditions, and you can adjust as needed.

Sun

Watermelons love the sun! If you’re just learning how to grow watermelon, you’ll need to know that they are definitely sun-worshipping plants. They create their own shade beneath their leaf cover for the vine and its fruit to stay protected.

Watermelons require 8 hours a day of sunlight to thrive. They will grow in shadier conditions, but the fruit may be smaller or less sweet.

Temperature and Humidity

When learning how to grow watermelon, temperature is a factor but not a major one to consider.

Watermelons grow best when the temperature is 70-90 degrees Fahrenheit during the day, and 65-70 degrees at night. However, watermelons are tolerant of hot summer temperatures, and can easily grow even in hotter conditions once established.

The time at which your watermelon vines will be most sensitive is when they’re still young, as they’re still vining and spreading out. Until the leaves create a canopy to shelter the vine beneath, you may want to use a shade cloth to cool the plants down if the heat spikes.

As for humidity, watermelons are happy in both semi-arid and humid conditions. However, the higher the humidity, the higher the risk of fungal diseases such as powdery mildew or downy mildew. Keep a watchful eye out for dangers such as these.

Watering

Orange Glo watermelon
An Orange Glo watermelon. The average melon is 92 percent water. Source: 305 Seahill

To make those juicy melons, watermelon vines need quite a bit of water. After all, a watermelon is made up of 92% water! But how do you know how often to water them?

Simply put, check the soil. Watermelons have deep roots, so you will need to check down deep. If it’s drying out in the top 2″ or so, you likely need to water again. Maintaining consistent moisture at all times will encourage sweet, delicious fruit later!

You’ll want the soil to be damp for at least 6″ below the soil’s surface when you finish watering. Using a drip irrigation system is usually the best way to achieve good permeation of water without putting the plant at risk of mildew or other fungal diseases.

Watermelons like to be watered deeply a minimum of once per week. Hotter weather means more watering. A good rule of thumb is that you should water them at least an inch per week during mild weather, and double the frequency in hotter weather.

If you plan on mulching, either with black plastic or wood chip mulch, you may not have as much evaporation from the soil and may be able to use less water. The goal is to keep the soil consistently moist but not soggy – watermelon roots, vines, and fruit are susceptible to disease.

Soil

Soil is an important part of how to grow watermelons, so let’s go over the optimal soil blends for them!

Hard-packed soils tend to be problematic as your plants will be struggling to stretch out their roots. It’s better to have a loamy, well-draining soil amended with compost. Aged manure or seaweed are also good additions, as watermelons are heavy feeders.

The optimal pH range should be 6.0-6.5, but your vines can handle up to 6.8 and maybe even 7 pH. Just be aware that anything below a 6 may result in yellowing leaves or vine stunting.

Watermelons are susceptible to manganese toxicity, especially if the pH range is not favorable for your plants. It’s always a good idea to have your soil tested at the local agriculture extension prior to planting so you can amend as needed.

Fertilizing

Moon and Stars watermelon rind
The unusual coloration of Moon and Stars watermelon rind. Source: DARLA SCHOENROCK

There are two stages of fertilizing which apply to watermelons: young plant, and fruit development.

A young plant is going to require a high nitrogen boost to do its growth spurt. So for the initial stage at and after planting, using a high-nitrogen fertilizer is best. That will provide all of the nutrition your watermelons need to develop their foliage.

When the vines begin to flower, it’s time to switch to a lower-nitrogen, but higher-phosphorous and higher-potassium fertilizer. The combination of potassium and phosphorous is necessary for stimulating flower production and for healthy fruiting.

Be sure that you make the switch, though! If you stick with the high-nitrogen fertilizer, your vines will continue to bolt everywhere, but you may not produce much, if any fruit at all. And the whole point of growing watermelon is to eat it, right?

Propagation

The best way to grow watermelons is from clean watermelon seeds. Plants grown from seed are typically healthier and have more vigor than those which aren’t. In addition, you can use a seed treatment such as beneficial mycorrhizae or other seed inoculant that way if you’d like.

Watermelon can also be grown from cuttings. You will need to examine your vine and take a cutting just past one of its leaf nodes. Ideally, you need a 9-12″ cutting. Place your cutting into sterile potting mix, burying at least a couple inches of the vine.

Keep the soil moist, but not wet, and ensure it remains in the 70 degree range. Also, keep your cutting out of direct sunlight until it starts to actively grow again, at which point it has developed roots.

Cuttings may have difficulty fruiting if they’re taken too late in the season. It’s usually far easier to just grow from seed in the first place.

Transplanting

Georgia Rattlesnake watermelon seedlings
Georgia Rattlesnake watermelon seedlings. Source: eakspeasy

Watermelons are notoriously finicky when it comes to transplanting. As these plants put down a sizeable taproot, it can start to coil around the inside of the pot and cause the plant to become rootbound quickly, which complicates transplants.

I highly recommend planting any watermelon seeds you wish to pre-start in a plantable pot, such as a pot made of peat or coconut coir. You can gently cut the bottom of the pot just before planting to allow easy access for the roots to stretch out.

Older watermelons do not transplant well at all. They develop a deep and intricate root system that can stretch out nearly a foot and a half from the vine’s base, and it seriously complicates any effort to move them. Since they’re a single-season crop, it’s not really necessary.

If you do need to transplant a watermelon seedling from a plastic pot, please be extremely gentle so as to not damage its main taproot. You can plant it at or just slightly above where it was planted before, as the vine will develop more roots along its length.

Pruning

Big watermelon
Big watermelon on the vine. Source: badorsey

Pruning watermelon vines can be tricky, because it may impact fruiting.

Watermelon vines are monoecious, meaning that they produce both male and female flowers on the same vine. While that means they’re self-pollinating, it also means that pruning may accidentally remove flowers you need to produce fruit.

Typically, male flowers tend to appear first on your vines, and female flowers will show up further along the vines later. There should always be some male flowers around when the vine is producing female flowers.

If you have the space to just let your vines grow at their own rate and size, then by all means you can! However, be aware that there are drawbacks to this method.

The more fruit that a particular plant is working to develop, the less sweet each fruit becomes. In addition, the quality of the melon will decline in other ways. The rind may be less solid, or the fruit inside may have a slightly mushy texture. Shelf life decreases as well.

Multiple vines emerge from the same plant. For the best, sweetest melons, you’ll want to decide on a maximum number of melons that each plant will produce. For smaller varieties, that might be 8-10 melons, but for larger melons, it may be 4-6.

If you’re trying to produce a prizewinning massive melon, you may want your plant to devote all of its time and energy to making one single melon. However, you don’t want to prune off all the other vines, as the plant needs leaves both to gather sun energy and to shade itself!

Once each vine from the plant base has a maximum of two fruit, it’s good to trim off the vine tip beyond that point, leaving enough leaves that the plant can continue to thrive.

People who are growing their watermelons on a trellis may be limited by the space available on the trellis, and should wait until some fruit starts to form. Again, try to limit it to a maximum of two fruit per vine. Then trim off excess growth to keep the plant in check.

As with any pruning, sterilize your pruners between cuts to prevent the spread of disease.

The Importance Of Mulching

There are three very important reasons to mulch around your watermelon vines: weed prevention, water retention, and disease prevention.

Weeds, especially those near the base of the vine, can compete with your plants for nutrients and water. They can also harbor pests which may go after your watermelon. Keeping the weed population down will help your plants significantly.

Soil that’s under a mulch layer will retain its water much longer, rather than losing it to evaporation. This slows down the need to water, although you’ll still need to water consistently nonetheless.

Watermelon vines are susceptible to a number of diseases, many of them fungal. The fruit is susceptible to rot where it sits on the ground if the soil beneath it is too moist. Mulching will keep water from splashing up onto the plants, and will also keep fruit off the ground safely.

Commercial farmers use black plastic or black landscaping cloth to mulch around their plants. Wood chips are also quite good. Avoid using compost as a mulch directly beneath fruit if you can, but compost around the base of the plant is also effective.

Training Watermelon Vines

Watermelon growing on chain link fence
A watermelon growing on a chain link fence. Keep an eye on your melons so they don’t surround the wire! Source: OakleyOriginals

Many commercial growers produce watermelons vertically. There’s good reason for this! It takes up far less space that way. However, knowing how to grow watermelon on a trellis requires you to be patient, and also requires you to be attentive.

Watermelon vines will take off in a rapid growth spurt once their roots are well established and their nutrition needs are met. It almost seems like you blink and it’s grown another few inches! During that initial spurt is when you’ll need to be most vigilant.

The method which commercial growers use most is overhead support. A strap will be placed around the end of the watermelon vine and attached to an upper support. As the vine elongates, the strap will be shortened to keep the vine upright.

You can also use a more standard trellis. Vertical trellises require some added support for the vines, so you may want to use strips of old plastic supermarket bags or twine to tie your vines to the trellis, which will help keep your vines growing upward.

If you happen to have a chain-link fence on your property, you have a ready-made trellis that can handle the weight of watermelon vines! Simply secure your vines to the fence. Be forewarned that if you’re growing a larger melon type, it may warp the chain link if it gets heavy.

Angled trellises are very simple to use. Place the short end of the angle at the base of the plant, and encourage the vines to grow across the top of the trellis “uphill”. Any fruit will hang down below the trellis as it develops. These are great for smaller melon types.

It’s important when you’re doing vertical watermelon growing to ensure that you have extra support for the fruit as it gets larger, too. Old pantyhose or T-shirt material works great to create a stretchy sling that you can tie to the trellis to hold the weight of your melon.

Harvesting And Storing Watermelon

Watermelon pile
A pile of freshly-harvested watermelons. Source: Ahmad Fuad Morad

Unlike many other fruits or vegetables, watermelons aren’t obvious when they’re ripe. In fact, they’re downright sneaky about it. They’re also not great for long-term storage. But I’ll give you the best tips to ensure you harvest at the right time and store the melons properly!

Harvesting Watermelons

It’s surprisingly difficult to gauge when watermelon is ripe. However, there are a few things which should be done when it’s getting close.

First, when the melons appear to be at full size, slow down watering. Keep the soil moisture consistent, but do not worry about providing heavy watering unless the plant needs it. This forces the plant to concentrate the sugars in the melon and makes it nice and sweet.

Watch the small tendrils close to where the vine attaches to the melon. These will begin to dry out when the melon is approaching ripeness. If they have gone completely brown, your melon may be overripe, but you want them to at least begin drying out.

The melon itself should have good color except for where it was resting on the soil or on whatever material you’re using to cradle it. Rather than being white, the lighter spot it was resting on should have turned creamish or yellowish in color.

Your melon should be nice and heavy for its size, indicating that it has plenty of moisture inside. The outer shell should be firm and should not easily give when pressed on. If it does give, the melon may already be overripe or suffering from signs of impending rot.

Many people thump watermelons as an indication, claiming that if it sounds hollow, it’s ripe. This is not universally true. It’s easier to pay attention to the vine tendrils and the melon’s color as a gauge for ripeness.

To harvest, use a clean, sterile knife or pruning shears to snip through the vine about an inch from the melon. Do not twist or break the vine off, as this will injure the vine.

It’s important to be aware that watermelons will not ripen any further once they’re cut off the vine. They will stay at the same level of ripeness until they start to decompose. So if you think your melon’s underripe, give it more time on the vine!

Storing Watermelons

Cut watermelon
Cut watermelon. Source: snowpea&bokchoi

Typically, a whole melon from the supermarket with no punctures to the rind will last at room temperature for a week or two. Every couple of days, turn your watermelon and inspect it, making sure it still is unpunctured and that it hasn’t started to soften.

Commercially-farmed melons are usually varieties with a much thicker rind than some of the homegrown types. Smaller homegrown varieties may have thin rinds, and thus will not last as long. These are best used within 3-5 days.

You can preserve a cut watermelon in the refrigerator by completely covering the cut surface with plastic wrap. Once cut, the inner melon flesh will begin to break down more quickly, so it’s best to eat it within a couple days of cutting.

If you dice up your watermelon into a bowl, moisture will begin to pool in the bottom of the bowl within 24 hours. It’s still fine to eat at that point, but the longer it sits, the less flavor the watermelon flesh will have.

Preserving Watermelon

Traditional Japanese watermelon Furoshiki wrap
A traditional Japanese furoshiki, or wrapping technique. This is used for short-term preservation and transport. Source: Mammaoca2008

Watermelon flesh does not freeze well at all. The cell structure of the watermelon flesh will expand and burst, and when it’s thawed back out, you will have damaged flesh and a puddle of juice. However, you can freeze watermelon juice with good success.

To freeze the juice, take the red (or orange/yellow) flesh of your melon and put it into a food processor or blender. Blend until mostly smooth. You can opt to leave the flesh pulp in or to strain it as you’d prefer.

Place the juice (strained or unstrained) into freezable containers, leaving at least a third of the container empty to allow for expansion when it freezes. Once it’s completely frozen into a watermelon icecube, you can remove it from its container and place it in a freezer bag if you wish.

Many people will also freeze ice cubes of watermelon juice and pulp. These can be added to smoothies or blended on their own to create a slushie.

If you have an ice cream maker, there are an abundance of recipes online for making watermelon sorbet, and that’s another great way to preserve summer’s sweet flavor.

Dehydrated or freeze-dried watermelon flesh is another option. The dehydration or freeze-drying process causes the moisture to fully evaporate, leaving crystalized watermelon sugar in the flesh. It creates a watermelon jerky that can be quite tasty!

Don’t forget that the rind itself is edible. While many people simply throw it away, pickled watermelon rind can be incredibly tasty and well worth storing. If you’re trying to maximize the produce that your garden gives you, try pickling your watermelon rind! You’ll be happy you did.

Troubleshooting Watermelon Problems

Desert King watermelon
An orange-fleshed Desert King watermelon. Source: unertlkm

Growing Problems

Blossom end rot is caused by a lack of calcium in the soil. Your plants need calcium to make healthy fruit! Prior to planting, you can add powdered eggshells or bone meal to the soil to prevent against this condition. It needs to be accessible to the roots.

Often, the soil pH may be off in gardens where blossom end rot is a regular issue for watermelons. Checking the soil pH and bringing it to a range between 6.0 and 6.5 will usually ensure the plants can have access to the calcium you’ve provided in the soil.

Pests

Yellow watermelon
A slice of yellow-fleshed watermelon. Source: lundyd

Common cucurbit pests are usually the culprits in your watermelon patch. Here’s a short list of the worst offenders!

The most common pest of watermelons is the cucumber beetle. Striped cucumber beetles are especially partial to watermelons, in fact. And the last thing you want to do is to discover these pests in your garden! Stop them with pyrethrins like Safer Brand Yard & Garden Spray.

Squash bugs can attack your vines and cause wilt damage or destruction. These are also susceptible to pyrethrin sprays, so Safer Brand Yard & Garden Spray is a good control method for them too.

While squash vine borers prefer squash vines, a healthy watermelon vine is hard for them to resist. These can be hard to spot in your watermelon patch, so it’s best to spray your plants weekly with neem oil to keep the borers at bay.

Both aphids and spider mites know that your watermelon vines are filled with plenty of sap for them to suck. As these can spread cucurbit diseases as well as other diseases, keep them at bay with regular sprayings of neem oil on all vine and leaf surfaces.

When your watermelon vines are still young, most of these pests can be prevented entirely by the use of floating row covers and good crop rotation. Once they’ve matured and are starting to flower, row covers should be removed to allow for pollination.

Diseases

watermelon and vine with tendrils
A watermelon and its vine. Notice the small curled tendrils above the melon which will dry out as it ripens. Source: thomas pix

Fusarium can wreak havoc in your watermelon plants. Younger plants are very susceptible to damping off, and older ones which are not properly cared for can develop root rot. There’s no real “cure” for this, but many tactics to use to prevent it. Read more on fusarium here!

Anthracnose, powdery mildew, and downy mildew are also all fungal diseases that hit watermelons. These are especially problematic if you regularly get your vines and leaves wet. Use drip irrigation to avoid these, and regular spraying of neem oil will help prevent fungal spores from taking hold.

Alternaria leaf blight is also fairly common in watermelons and other cucurbits. Spread by fungal-contaminated water, it’s best to drip-irrigate to avoid splashing and spread of fungal spores. Copper fungicides like Monterey Liqui-Cop are recommended if it still takes hold.

Curly top virus is a common disease of tomatoes, cucurbits, and other vegetable crops. This virus is spread by leafhoppers, and there’s no treatment once a plant has it. Preventing the leafhoppers with neem oil or Safer Brand Yard & Garden Spray is your best bet.


Summer’s sweetest fruit is well within your reach! Now that you know how to grow watermelon, which varieties appeal most to you? Tell me down below in the comment section!

Learn how to grow watermelon the right way with our ultimate guide to this popular summer fruit! We'll show you everything you need to know.
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4 thoughts on “How To Grow Watermelon: The Ultimate Guide To Summer’s Bounty

  1. Thank you for such a thorough article! I’m in the PNW zone 8b (?) and am considering growing watermelons in a container. It’s July now, so I may be too late, but I was thinking of bringing the watermelon indoors to put under LED lighting if our summer is short.

    • If you can find young watermelon transplants at a local store, you may be able to make it work even now! However, you’ll need to trellis-train your plants, and you’ll want a large grow light to provide enough surrogate sun for your plants. You’ll also need to be religious about watering, as they require quite a bit of water to produce fruit.

      You might be able to do one of the short growing-season icebox varieties as an outdoor/indoor plant as well. There’s a few listed in there. Check out Little Baby Flower, Little Darling, Mini Love, Golden Midget, Kaho, or Sunshine — those are much faster to develop fruit and typically do quite well when container-grown.

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