How to Grow Watermelons: A Step-by-Step Guide for Sweet, Juicy Harvests

Chomping down on a succulent slice of watermelon is pretty much synonymous with summer vibes. Imagine this: you’re at a sunny barbecue or a laid-back picnic, and there it is, a big, cool platter of watermelon slices that instantly beats the heat.

If you’ve only ever snagged your watermelons from the local grocery store, let me tell you, you’re not getting the full taste experience. Growing your own watermelons lets them soak up the sun right up until they’re perfectly ripe, enhancing their sweetness. Plus, nothing beats the convenience of plucking one right from your backyard and serving it fresh.

Ready to dive into the world of homegrown watermelons? Here’s how to kick things off. First, pick the type of watermelon you want to cultivate. You’ve got your early season, main season, and seedless varieties to consider. Each type comes in colors like classic red, pretty pink, sunny yellow, or vibrant orange.

If you’re short on space or just starting, an early-season watermelon, also known as an icebox melon, is perfect. These smaller melons mature quickly, in about 70 to 75 days, making them ideal for squeezing onto a fridge shelf.

On the other hand, main-season watermelons are the big boys, taking a bit longer, around 80 to 90 days, to reach full ripeness. And if you’re not a fan of spitting out seeds, go for a seedless watermelon. They tend to be sweeter as they put all their energy into growing juicy flesh rather than seeds, and their vines thrive robustly through the summer.

Watermelons love the heat, thriving in those balmy summer days. They’re surprisingly easy to grow in your garden and deliver a burst of flavor that store-bought melons just can’t match. Dive into the joys of planting, nurturing, and finally harvesting your own watermelons this season.

All About Watermelons

Bring the taste of summer into your own backyard by growing watermelons! Belonging to the gourd family, alongside squash, cucumbers, and pumpkins, watermelons (Citrullus lanatus) thrive in warm conditions and enjoy soaking up the sun.

These sprawling vines yield delicious fruits that can weigh anywhere from 6 to 50 pounds, depending on the type you choose. Typically, their flesh comes in shades of red or yellow and is surrounded by a rind that’s not only edible but can also be pickled for a tangy treat.

Cultivating watermelons is less complicated than you might imagine and proves to be incredibly satisfying. Start your seeds about two weeks after the last frost when the soil has warmed up, aiming for a growing period of 65 to 100 days until the melons ripen.

Whether you’re looking to impress at a summer BBQ or just want to share some home-grown sweetness with friends and family, mastering the care of watermelon plants can make you the hero of the season.

Watermelon Overview

For optimal growth, watermelons favor sunny spots with fertile, well-draining soil. Before planting, enhance the soil by mixing in organic material and a balanced fertilizer. Directly sow your seeds in the soil once it reaches 65°F, burying them 1 to 2 inches deep in mounds spaced 4 feet apart. After germination, thin the seedlings to two per mound.

For an early harvest, consider transplanting seedlings through black plastic and safeguard them with row covers if you’re planting before the last frost date. To promote strong growth, apply a nitrogen-rich side dressing once the vines start to sprawl and maintain deep, but spaced-out watering.

Using both plastic and organic mulches can conserve moisture and minimize weeds—just wait until the soil is at least 75°F before applying organic varieties. Keep an eye out for pests and diseases throughout the season, and pick your watermelons when the tendril nearest the fruit dries up, the belly of the melon turns yellow, and the exterior dulls.

While watermelons prefer extended warm periods, cultivators in cooler regions can still enjoy success by choosing shorter-season varieties, starting seeds indoors, or purchasing young plants.

Depending on your chosen variety, it may take 70 to 100 days from planting to harvest. Favorites like Crimson Sweet, MickyLee, and Yellow Baby are all excellent choices for any garden enthusiast looking to grow their own slice of summer.

When to Plant Watermelons

If you’re planning to grow watermelons, timing is crucial, especially depending on your local climate. Here’s how to get started:

• For those in cooler regions with brief growing periods, it’s wise to begin your watermelon seeds indoors. Do this about two to three weeks before the frost disappears for the season. Once the risk of frost has passed and the soil is nicely warmed to at least 65°F (18°C), move your seedlings outside.
• If you’re in a warmer area where the growing season stretches longer, you have the luxury of planting seeds directly in your garden. Just wait for one to two weeks after the last frost and ensure the soil is at least 65°F (18°C) before sowing.
• You might also consider purchasing young watermelon plants from local nurseries if you prefer a head start. These should be planted once you’re confident there’s no further frost threat. To help the soil warm up a bit more, you might want to cover the ground with black plastic before planting.
• A handy tip: starting with nursery-bought plants could mean enjoying your watermelons up to two weeks sooner than usual, particularly beneficial in cooler climates.

For direct sowing, make sure your garden bed is ready. Plant the seeds about one inch deep into small mounds that are roughly two feet wide and five feet apart. Sprinkle five or six seeds on top of each mound. After the seedlings sprout and begin to grow, thin them out, leaving only the three strongest plants per mound.

In cooler northern areas, the season might not be warm enough to grow watermelons directly from seeds. In this case, start the seeds indoors in a soilless mix a few weeks before the end of frost season, keeping the seedlings warm and moist. Be careful not to start too early, as watermelons that grow too big indoors tend not to transplant well.

Finally, once your watermelon vines start to flower, successful fruit development depends on pollination. It’s vital to attract bees and avoid using insecticides that could harm these beneficial pollinators.

Selecting the Ideal Location for Watermelons

When setting up your watermelon garden, it’s crucial to choose a sunny spot because these fruits thrive under full sunlight. Watermelons demand a fertile, well-drained, sandy soil. Ideally, the soil should have a slightly acidic to neutral pH, ranging from 6.0 to 7.5. Before you plant, it’s a smart move to test the soil to figure out the specific nutrients it might be lacking.

Enhance your garden’s soil by mixing in some aged manure, seaweed, or compost. Since watermelons are big on nutrients, enriching the soil beforehand ensures they get the nourishment they need to grow robustly. For optimal growth, avoid heavy, clay-rich soils that tend to retain water and impede drainage.

Watermelons are sprawling plants, so they need plenty of room. Ensure each plant has about 20 square feet of space to allow for unrestricted vine growth. For better water drainage and to keep the warmth from the sun a bit longer, consider planting your watermelons on raised mounds or hills.

Typically, space the plants about 2-3 feet apart if they are in hills that are about 5 feet wide. If you’re planting in traditional rows, keep them at least 6 feet apart to prevent overcrowding and to promote healthy growth.

Growing Watermelon from Seed

Growing watermelons from seed is quite straightforward, though they don’t fare well in cool soil. For optimal germination, ensure the soil temperature is between 60°F and 65°F at a depth of four inches before planting your seeds.

Watermelons, along with their relatives cucumbers and squashes, thrive when sown on raised mounds of soil. This technique not only warms the soil quicker but also enhances drainage and accelerates the seedlings’ growth.

Here’s how to plant your watermelon seeds:

• Plant seeds outdoors at a depth of 1/2 to 1 inch, or indoors in seed-starting pots at 1/4 to 1/2 inch deep.
• Tip: Opt for larger pots for initial planting to encourage more robust root development. Compostable pots are great because you can plant them directly in the ground, which helps avoid damage to the fragile roots when transplanting.
• When sowing directly into the garden, plant about 4 to 6 seeds per mound, and thin them out to the strongest 2 to 3 seedlings later on.

If you’re interested in cultivating seedless watermelons, start with young plants rather than seeds. Refer to the spacing guidelines on your seed packet, as different varieties might need more room to flourish. Generally, space your plants 36-48 inches apart, in rows that are 6 to 8 feet apart to give them plenty of room to grow.

Starting Your Watermelon Seeds

1. Prepare your garden bed by adding fertilizer as needed.
2. Construct small mounds of soil, approximately 6-8 inches tall and 18-24 inches wide. Space these mounds as per the specific variety’s requirements.
3. Plant four to five seeds in each mound at a depth of about one inch.
4. Ensure the mounds are well-watered and keep the soil consistently moist to aid germination.
5. About a week after the seedlings appear, thin them to the strongest two per mound using scissors or flower snips.
6. Mulch around the plants with materials like dry grass clippings, straw, or wood chips to suppress weeds and retain soil moisture.

Growing Watermelons from Transplants

If you’re keen on harvesting watermelons a bit sooner, consider starting with transplants from your local nursery. Seedless watermelons, in particular, are better off begun as young plants because their seeds can be pricy and slow to sprout. By choosing transplants, you can enjoy your juicy fruits roughly two weeks ahead of schedule compared to starting from seeds.

• Transplanting Tips

When it’s time to move your watermelon seedlings to the garden, handle them with care to avoid damaging their delicate roots. Ease the seedlings out of their containers without shaking off the soil. It’s helpful to use seedlings that come in peat pots, as these can be planted directly into the ground, reducing stress on the plants.

Once your watermelons are in the ground, shield them with row covers to protect against pests. Be sure to remove these covers once the male and female flowers appear to ensure that pollinators can do their job.

For planting, use the same spacing guidelines as you would for seeds. Place two robust transplants on each mound, adhering to the recommended distances. Water the plants deeply, aiming for at least six inches down. Regular irrigation, ideally through a drip system, will promote strong growth.

• Container Growing

Not to forget, watermelons can thrive in containers as well. Opt for compact, bush-type varieties and select a large pot, holding at least 8-10 gallons of soil, with excellent drainage. Regular watering and feeding are crucial to keep the plants healthy and productive.

Growing Seedless Watermelons 

Cultivating seedless watermelons is a fascinating exploration of plant breeding. To begin, seedless varieties require multiple breeding steps to produce plants that are incapable of developing seeds on their own yet are able to bear fruit.

These plants rely on pollination from seeded watermelon varieties, which should be planted nearby. When starting seedless watermelons, it’s wise to plant extra seeds indoors using peat pots since their germination rates can be lower. Once they sprout, care for them just as you would seeded watermelons.

• Ensuring Your Watermelons Are Sweet

Ever wonder why some watermelons are bursting with sweetness while others are bland and stringy? The secret lies in the care of the plants. Ensuring your watermelons get ample water, disease protection, and the right nutrients throughout the growing season is crucial.

Additionally, cooler temperatures during the growing season can impact the sweetness of your watermelons, making it important to monitor and adjust your gardening approach accordingly.

Caring for Watermelons

Watermelons relish the sun and need a generous amount of space and water to flourish. These plants stretch out as lengthy vines adorned with curly tendrils and sizable, lobed leaves.

While standard watermelon varieties can sprawl over 6 feet, there are also compact and bush-type options suited for limited spaces. Remember, pollinators like bees are crucial in the watermelon patch since these plants bear separate male and female flowers which require pollination by honeybees, native bees, and other pollinating insects.

• Sunlight Requirements

To ensure your watermelons flower and bear fruit abundantly, plant them in a spot that receives between eight to ten hours of direct sunlight daily. These conditions are vital for nurturing the sweetest melons.

• Soil Preferences

Warm, well-drained soil is vital for watermelons. They adapt well to various soil types but thrive in loamy and sandy loams. Ideal soil conditions include rich, well-aerated dirt with a pH ranging from 6.0 to 6.5.

To combat weeds and retain soil moisture, spread a 1- to 2-inch layer of organic mulch around the plants when they are about 6 to 8 inches tall. It’s best to remove weeds early on to avoid root disturbance later.

• Watering Techniques

Watermelon’s name hints at its needs; the fruit is 92% water, after all. These plants, with their shallow root systems, need about 1 inch of water weekly. To optimize water use, distribute this amount in several watering sessions throughout the week, depending on your soil type.

Watering should be frequent from planting until the fruit starts forming. It’s crucial to keep the soil consistently moist but avoid waterlogging. Water directly at the base of the vine in the early hours to prevent leaf wetness and reduce watering as the fruit matures, as drier conditions tend to enhance the sweetness of the melons.

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• Temperature and Humidity Adaptability

Watermelons prosper in warm climates, ideally where temperatures soar above 80°F. In cooler or shorter summer regions, using black plastic to cover the soil can help retain warmth. Ensure the cover has holes to allow moisture through.

These plants perform well under various humidity levels, provided the soil drains well, although high humidity can encourage disease. Drip irrigation or morning watering can help manage humidity-related issues.

• Fertilization Strategy

While some gardeners opt to fertilize, it’s crucial to choose the right type of fertilizer. Initially, a balanced 10-10-10 fertilizer is beneficial. However, once flowering starts, switch to a fertilizer lower in nitrogen to promote more blooms and fruit development.

An initial application of fertilizer before planting and a nitrogen-rich side dressing as the vines grow can support healthy growth. Yet, be cautious not to over-fertilize, as too much nitrogen can lead to more vines and fewer fruits.

• Pollination and Fruit Development

Watermelon vines carry both male and female flowers separately. It’s common for male flowers to appear first and drop off; however, the female flowers, recognizable by a tiny bulge at their base, are the ones that transform into fruit.

It’s crucial to keep bees buzzing happily in your garden, as they are necessary for the flowers to turn into melons. To prevent your growing fruits from rotting, prop them up with straw or cardboard to avoid direct contact with the soil.

• Essential Care Tips for Watermelons

Laying down a layer of straw or black plastic mulch around your watermelon plants does wonders. It not only warms the soil and suppresses weed growth but also keeps the fruits clean and off the ground.

While watermelon plants typically don’t require pruning, managing the vines can boost fruit production. Limit growth to the main vine by snipping off side shoots and buds early on. You might also consider thinning some flowers to concentrate the plant’s energies on fewer, but larger, melons.

• Growing Watermelons in Small Spaces

Not everyone has the luxury of a large garden, but that doesn’t mean you can’t grow watermelons. Opt for compact varieties suitable for container gardening in pots of 5 gallons or more with adequate drainage. Fill the container with a lightweight potting mix, not dense garden soil, to ensure healthy growth.

After the frost risk is over, plant a few seeds or a seedling deep enough into the soil and water adequately. For vertical growth, set up a trellis or teepee to support the vines and use fabric slings to support the fruits as they grow. Since watermelon plants are annuals, they won’t require repotting.

Understanding Watermelon Growth Timelines

Growing watermelons takes a bit of patience since they aren’t the fastest to ripen. Typically, it takes anywhere from 65 to 100 days for the fruit to fully mature after planting, depending on the type.

While it’s generally true that smaller varieties might ripen a bit sooner, there are exceptions. To get a clear idea, always check the seed packets or catalogs where the expected time to harvest is often noted as “days to maturity.”

If you’re in a hurry for some juicy melons, go for varieties labeled with fewer days to maturity, and those that include “early” in their name might be your best bet. Another quick tip is to buy transplants instead of seeds. This shaves off about two weeks, since the plants are already somewhat grown.

For those who love a steady supply of fresh melons throughout the season, consider planting both early-ripening types and those that take a little longer. This way, you can enjoy fresh watermelons from mid-summer all the way to late summer.

Harvesting Watermelon

Watermelons stop ripening once they’re picked, making the right harvest time crucial. Here’s how you can tell if a watermelon is ripe without relying on the old “thump” test, which isn’t very reliable:

• Check the ground spot: Initially pale green or white, this spot on the watermelon turns yellow when it’s ripe. Lift the melon gently to avoid harming the vine and sneak a peek at the spot.
• Examine the tendrils: Near the stem, these green, curly tendrils dry and turn brown on ripe melons.
• Look for a matte finish: Ripe watermelons have a dull surface, not a shiny one.
• Nail test: A ripe melon’s skin is tough enough to resist a fingernail poke.
• Hollow sound: When thumped, a ripe watermelon will emit a hollow sound.
• Stripe contrast: A ripe watermelon shows little contrast between its stripes.
• Bottom color: Ripe watermelons have a cream or yellow bottom, not white.
• Softness on pressing: Though not recommended by everyone due to potential damage, a slight give upon pressing can indicate ripeness.
• Tendril condition: A green tendril means wait, a half-dead one suggests near ripeness, and a fully dead tendril indicates the melon is ripe or overripe.
• Cutting the stem: Use a sharp knife to cut the stem close to the fruit when harvesting.

Figuring out the best time to pick a watermelon can be tricky since they don’t ripen after being harvested. While the melon’s rind might change color as it matures, this isn’t always a sure sign. The tendril near the fruit is a more reliable indicator; it turns dry and brown when it’s time to harvest.

Other signs include a dull skin coating and a hard-to-pierce rind. The true test, however, is cutting the melon open—experience will guide you in identifying the peak time to enjoy each variety.

How to Store Watermelons:

• Unopened, watermelons last about 10 days. Once cut, they should be kept in the refrigerator, tightly wrapped in plastic, for up to four days.

Exploring Watermelon Varieties for Your Garden

When you’re deciding on which watermelon types to plant in your garden, the first thing to think about is the amount of space you have. Watermelons can be quite space-hungry, needing anywhere from 18 to 24 square feet for each plant.

If your garden is on the smaller side, don’t worry—there are compact options available, such as the petite “icebox” melons and bush-type varieties.

Choosing seedless or seeded varieties is also crucial. Seedless watermelons are great if you prefer not to deal with seeds, although it means missing out on fun seed-spitting contests. It’s wise to opt for varieties that resist diseases too. If you’re looking to harvest your melons quickly, consider early-maturing types.

Here are some popular watermelon varieties to consider:

• ‘Crimson Sweet’: These are round, 15-25 pound melons with a light green, dark-striped skin and dark red, firm flesh. They’re resistant to anthracnose and fusarium wilt.
• ‘Jubilee II Hybrid’: Known for its oblong, green-striped melons that weigh 30 to 40 pounds and have delicious red flesh. This variety thrives in the Southeast and fights off common diseases well.
• ‘Moon and Stars’: An heirloom variety, famous for its unique yellow spots on the dark green rind. It produces large, tasty melons weighing between 25 and 40 pounds.
• ‘Sugar Baby’: This variety is perfect for smaller spaces. The round, deep green melons have red flesh and are known for their thick skins that resist cracking, weighing in at 8 to 10 pounds.
• ‘Sweet Beauty Hybrid’: Producing 5-7 pound fruits, this variety is ideal for small families. The melons have sweet red flesh and grow on semi-upright vines.
• ‘Tiger Baby’: These melons are round and striped, weighing 7 to 10 pounds each. They have dense, sweet pinkish-red flesh and show good disease resistance.
• ‘Yellow Doll Hybrid’: A unique variety with yellow flesh, producing 3-6 pound melons on compact vines.
• ‘Sugar Baby’: Matures in 80 days and produces bright red flesh within 10-pound melons. These smaller fruits can be planted just 4 feet apart.
• ‘Sweet Beauty’: Also matures in 80 days, a 2004 All-America Selection, producing oblong 6-pound melons with red flesh.
• ‘Golden Midget’: A good choice for Northern gardeners with just 70 days to maturity. These small melons have yellow skin and pink flesh, weighing around 3 pounds.

Common Pests & Plant Diseases

Growing watermelons brings its share of obstacles. One common issue is misshapen watermelons resulting from inadequate pollination. To boost pollination, try planting flowers full of nectar near your watermelon vines to attract bees and other pollinators. Also, too much fertilizer or not enough space between plants can hinder fruit development.

Watermelons are also prone to several diseases, such as anthracnose, fusarium wilt, gummy stem blight (known as black rot), and bacterial wilt. It’s wise to buy seeds from a trusted source and opt for varieties that are resistant to these diseases.

When buying transplants, be vigilant for signs of disease like dead patches on leaves or stems that appear wet, oozing, or soggy.

Rotating your crops is an effective strategy to keep disease at bay. Make sure to plant watermelons, cucumbers, squash, and similar crops in different areas of your garden each year, avoiding repeating locations for at least three years.

Additionally, to prevent diseases like blossom end rot, use drip irrigation or water early in the day so the foliage has time to dry under the sun, and keep the soil evenly moist.

For insect control, particularly from pests like striped and spotted cucumber beetles, squash bugs, and aphids, protective measures are crucial during the early stages of plant growth. Using row covers can help shield your plants, but remember to remove them when flowering begins to ensure that pollinators can do their job.

For a safer approach to dealing with pests, consider using organic methods like insecticidal soaps or physically removing pests and dropping them into soapy water, especially if you plan to eat the fruits.

Lastly, if pests persist, covering young watermelon plants with row covers can offer protection, but don’t forget to remove these covers as soon as flowering starts to avoid interfering with pollination.

Frequently Asked Questions

• Do watermelons require support to grow?

While watermelons naturally spread across the ground, they can benefit from being trained to grow on a trellis. This elevation not only exposes them to more sunlight but also enhances air flow around the plants, reducing the risk of diseases and pest infestations.

If you choose to let them grow on the ground, consider placing a layer of straw or cardboard beneath the fruits to prevent them from touching the soil directly.

• Why are there flowers on my watermelon plant but no fruit?

If your watermelon is flowering without bearing fruit, it’s likely due to a lack of pollination. Introducing companion plants into your garden can attract bees and other pollinators, which are essential for fruit development.

• What plants should be kept away from watermelons?

Avoid planting watermelons near other members of the Cucurbitaceae family, like squash, cucumbers, and pumpkins. These plants tend to attract cucumber beetles, which can harm the foliage, vines, and fruits of watermelons.

• Which states are the top producers of watermelons?

Florida leads the pack in watermelon production within the United States, followed closely by California, Georgia, and Texas. Together, these four states are responsible for producing 80 percent of the nation’s watermelons.

• What are the white seeds in watermelons?

The white “seeds” in watermelons are actually seed coats where the seeds failed to develop. They are perfectly safe to eat and cause no harm.

• Is it better for watermelons to grow on a trellis or on the ground?

Watermelons can grow well either way. Ground cultivation is common, but using a trellis, slings, or hammocks can improve air circulation and minimize disease risks, irrespective of the support material used.

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