Watermelons are delicious fruits that taste so much better if you have grown them yourself at home. Easy to grow in warmer climates but more challenging in cooler zones. This is a crop that is well worth growing if it is possible where you live.
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Are watermelons easy to grow?
Whether or not watermelons are easy to grow very much depends on where you live, how warm it is there, the soil and other conditions, and the length of your growing season.
If you live in a warm and sunny location, growing watermelons is a breeze. If you live in a cooler location with a shorter growing season, you can often still grow watermelons but may find it somewhat more of a challenge.
Watermelon plants can, in warmer climates, grow almost like a weed, taking over huge areas if you let them. In cooler climates, however, it will take a bit more work to get the fruits to fully mature before colder weather arrives.
However, even where it can be more of a challenge – don’t let this put you off. There is nothing quite like the taste of your own home-grown, sun-warmed watermelon that’s fresh from the garden (or a polytunnel in cooler climes).
Understanding where watermelons will thrive and where they will be somewhat more challenging to grow involves looking at where these plants come from and the conditions in which they prefer to grow.
The watermelon plant, Citrullus lanatus, is a domesticated plant bred from wild species that originated in Tropical and Southern Africa. These plants are widely grown across tropical, sub-tropical, and warm-temperate climate zones and are typically grown outdoors in USDA zones 8-11.
If you live in a lower zone, watermelons will be far more difficult and time-consuming to grow. However, with the right strategies, it is often still possible to do so.
The main limiting factor is the length of your growing season, but summer temperatures are also important. These plants typically require temperatures above around 25 degrees C. (77 degrees F) to thrive. If summers are not consistently above this temperature where you live, watermelons are best grown in a polytunnel or other undercover growing area that provides warm temperatures.
What watermelon varieties are easiest to grow at home?
There are numerous different watermelon varieties to grow, and which one will be easiest depends on a range of factors, including temperatures and other growing conditions, and how much space you have available in your garden.
If you live in a warmer climate, you will have a lot more choices when it comes to which variety of watermelon you can grow.
If a lot of space, you can choose even enormous types, which sprawl over large areas and have gigantic fruits.
If, however, space is more limited, you might wish to opt for a variety with smaller fruits, such as sugar baby, so you can train the watermelon vines up onto a trellis or other support. There are also dwarf watermelon plants to consider that don’t grow into such space-consuming plants.
If you live in a cooler climate, then you should look for varieties that do better in cooler areas. These take a shorter period of time until the fruits are ripe and ready to harvest.
Look for options that are early ripeners that will be ready within 70-80 days of sowing if you are contending with a short growing season – rather than those that can take over 100 days to reach the harvest time.
Wherever you live, think about seeking out heritage varieties that are grown in your area, as well as embracing commonly grown commercial varieties. Heritage crops may be easier to grow because they have been bred in the conditions that you can provide where you live.
Should I grow watermelons from seeds or from plant starts?
In warmer climates, watermelons thrive. With long growing seasons, high summer temperatures, sunny weather, and warm soil, the best way to grow watermelons is from seed. As a warm-weather annual, sow watermelon seeds directly into the ground where they are to grow.
This is because watermelons are not particularly tolerant of transplantation and don’t really like to be moved.
However, when growing watermelon in cooler climates, you will typically need to sow seeds indoors. Doing this allows you to extend your growing season. Start seeds indoors earlier in the year before transplanting them to your garden once the weather warms in order to extend the growing season and get ripe fruits before cold weather arrives once more.
There are steps that you can take to reduce the chances of problems during this time and increase the chances of transplantation going well. We will discuss these later in this article.
While you may be able to purchase starts, there is really no reason to do so. Since seeds germinate relatively easily and seed sown plants will catch up very quickly to those planted as young plants.
When should I plant watermelon?
When you should sow or plant watermelons depends on where you live. Though it will be in the spring, close to the beginning of your main growing season. Whenever temperatures reliably warm where you are.
It is best to sow seeds outdoors once the soil temperatures reach 21 degrees C. (70 F) and air temperatures where you are growing the watermelons are consistently above 60 F.
In colder climates, you will sow indoors a few weeks before you expect to plant out your young watermelon seedlings.
This is a summer crop that you will sow or plant out in your garden once temperatures warm. While watermelon needs a relatively long period in the garden before harvest, it is important not to sow or plant too early. If you do, the plants may be set back by cold and experience a check in their growth.
If you have sown seeds indoors to get an early start on the process or purchased starts in a colder climate, these should be planted out in the garden once the weather has warmed reliably and there is no longer danger of a frost.
What soil conditions do watermelon plants prefer?
One of the most important things to get right if you want to grow watermelons successfully in your garden is providing the right soil conditions.
Watermelons are relatively ‘hungry’ plants, requiring good nutrition. So it is important to make sure that you are growing these plants in a fertile and nutrient-rich soil or growing medium. The ideal soil types for growing watermelons are sandy or sandy-loam soils enriched with organic matter.
The soil also has to be sufficiently warm for watermelons to thrive. Remember, the soil should be at 21 degrees C. (70 F) for watermelon to thrive.
It is also important to ensure that you provide slightly acidic soil or neutral soil in order to achieve the best yields. The ideal soil pH will be between 6 and 7. A soil test kit can be purchased to check soil pH.
Another thing to consider is that the soil should be able to retain sufficient water for the watermelons while also providing relatively good drainage conditions.
What light conditions do watermelon plants prefer?
Another of the most important things when growing watermelons is to make sure that they get enough sunlight. Heat and light are both vital to get these fruits to grow and ripen successfully.
It is absolutely crucial to grow watermelons in full sun, where they will get at least 8-10 hours of sunlight per day.
In cooler areas, it is especially important to maximize sun exposure and to grow your watermelons in as warm and sunny a location as possible.
Step-by-step Instructions: How To Grow Watermelons At Home
Growing watermelons successfully at home, even in the optimal climate and environment where it is a lot easier, does involve taking the right steps and following the right process at each stage. From choosing which watermelons to grow to harvesting the fruits of your labor.
1. Choose which varieties of watermelon to grow.
Above, we discussed some things that you should think about when choosing a watermelon variety to grow.
It is important to put some care and thought into this stage of the process because selecting wisely will have an important bearing not only on how easy you find the process of growing watermelons at home but also on the size and quality of the yield you are able to achieve.
2. Decide where to grow your watermelon.
Once you have selected a variety or varieties to grow, the next step is to decide where and how precisely you will grow your watermelon plants.
Remember, watermelons require the following growing conditions:
- Full sun – at least 8-10 hours of sunlight per day.
- High temperatures – soil temperatures and air temperatures that are reliably warm.
- Fertile, moist yet free-draining, slightly acidic to neutral soil. (Well-drained soil such as sandy soil or sandy loam soils are ideal.)
In a warmer climate, these conditions will be relatively easy to provide. In a cooler climate, you may need to work harder to provide them.
Where temperatures are a little cooler, growing watermelons in a sheltered spot, close to a sun-drenched stone or brick wall, could help you to create the perfect micro-climate for this crop.
In colder areas, growing watermelons will require an undercover growing area, such as a greenhouse or polytunnel.
One important decision that you will have to make is whether you will grow watermelon vines to sprawl freely across the ground. Or, will you train them to grow upwards on some form of support?
3. Prepare your growing area and any supports required.
Once you have decided on a general growing location and strategy, you will need to prepare your growing area. In addition, any support structures that you may have decided to use.
Amend the soil in the growing area by sheet mulching with plenty of organic matter. Homemade compost or well-rotted manure are great options. Where necessary, add sand to improve drainage or take steps to provide optimal pH levels.
In some areas, it may also be necessary to warm the soil before sowing or planting. Using cloches or row covers over the planting area can be beneficial. While some people recommend using black plastic sheeting, I would not recommend this as it can cause damage to the soil ecosystem and kill off essential microbial life.
Another idea to consider in cooler climates is creating a hotbed to grow plants like watermelons that like things as warm as possible. This is a type of raised bed with compost below, which gently gives off heat as materials decompose, warming the growing area above.
4. Sow seeds or plant starts.
As mentioned above, it is best where possible to sow watermelon seeds directly into the ground or raised bed where they are to grow.
But in colder climates with shorter growing seasons, you will typically have to sow indoors before later transplanting young plants into your garden.
Direct Sow Outdoors
When sowing outdoors, plant your watermelon seeds around 1/2 inch deep on mounds or in rows, around 36 inches (or approximately 1m) apart. Plant 2-3 seeds at each station in a row or ~8 seeds on a mound. Then, once true leaves have formed, snip off the extra seedlings leaving one seedling per station in a row or 2-3 young watermelon plants per mound.
When sowing indoors, it is best to use soil blocks or biodegradable pots so that you can transplant the seedlings without root disturbance, transferring the whole thing into your final growing position.
Make soil blocks or fill your biodegradable pots with a suitable seed-starting medium. Any peat-free seed starting compost mix can work well, though it is a good idea to add horticultural sand to improve drainage.
Sow 2-3 seeds per block or pot, again around 1/2 inch deep. Place somewhere warm (on a heat mat or in a heated propagator where necessary). Maintain temperatures of between 75 and 85F (c. 23-30 degrees) to provide optimal conditions for successful germination. Seedlings should emerge within a week or two.
Thin seedlings by cutting them off at the base of the stem, leaving one per pot or block once the first true leaves emerge.
Grow your seedlings in warm, light conditions, keeping them moist but making sure excess water can drain away. Then harden them off (gradually acclimate them to outdoor growing conditions) before planting them out once the weather has warmed reliably where you live.
5. Lay organic mulch around your watermelon plants.
Since watermelons like fertile growing conditions, ensuring that the growing area remains nutrient-rich through the growing season is important.
Laying an organic mulch or compost, well-rotted manure, or other organic materials around your watermelon plants is perfect. Maintaining this through the growing season will help to provide slow-release nutrients. Carbon-rich materials like straw or wood shavings layered on top, around the plants will also help to reduce moisture loss from the soil and suppress weeds.
6. Water watermelons well through the growing season.
Watermelons need consistent water through the growing season. Especially while they are setting and growing fruits. Make sure that you water well through the growing season, providing more water if growing undercover or if the weather is very dry.
Typically, watermelons require around 1-2 inches of water per week. But remember, water needs will vary depending on the environmental conditions. Drip irrigation can be a water-wise way to make sure a watermelon plant’s water needs are met.
One other departure from the norm – but an interesting option to consider. Growing watermelons in a large wicking bed with a reservoir of water at the base works too.
7. Feed watermelons for the best results.
Preparing the soil and adding mulches through the growing season will help provide watermelons with the nutrients they need. But it can also be beneficial to use organic feeds to ensure optimal nutrition.
It is a good idea to provide nitrogen-rich organic feed while the foliage grows. Then a potassium-rich organic feed once the vines flower and set fruits. An organic liquid plant feed can be applied while watering your plants.
8. Consider pollination.
Providing the right nutrients can help ensure a successful fruit set. But it is also very important to ensure that pollination takes place. Watermelons are an insect-pollinated crop and will fruit best when insect pollinators are around.
You can help ensure pollinators are present for your crops by ensuring good biodiversity in your garden and choosing companion plants (see below) to draw pollinators to the area where your watermelons are growing.
When growing watermelons in a greenhouse or polytunnel, it is important to make sure pollinators can enter the space during this crucial time. But in certain instances, you may need to hand-pollinate watermelons along with certain other crops.
(Pollination is a particularly important thing to consider if you would like to grow seedless watermelons. Seedless watermelons, also known as triploid watermelons, are produced by crossing a diploid melon with a tetraploid one. But for the seeds to grow into seedless plants, the female flowers on the plant must be pollinated by the male flowers of a regular seeded plant.
To achieve this in a home garden you need plenty of pollinators around. You also need to grow at least one seeded watermelon per every 2-3 seedless variety ones that you grow. )
9. Keep your eyes peeled for pests & disease
Most issues that arise when growing watermelons relate to deficiencies in environmental conditions and care.
However, there are also certain pest and disease issues that can arise. For example, fungal problems such as anthracnose, downy mildew, powdery mildew, and gummy stem blight. Bacterial diseases such as bacterial fruit blotch. Pests like aphids, caterpillars such as armyworms, cucumber beetles, etc.
Pests and diseases should be managed organically, and prevention is better than a cure. Ensure plants are healthy by following the care instructions above, boost biodiversity in your garden for a healthy ecosystem balance, and remain vigilant so you can nip any problems in the bud.
10. Protect fruits as they grow
As the fruits grow, you should remain vigilant to protect fruits from pests, and you should also protect fruits in other ways.
Raise fruits off wet soil to reduce disease and potential rotting. If you are growing watermelon vines up supports, use melon nets to support the weight of the fruit and prevent damage or losses.
11. Harvest your watermelons
Harvest your watermelons when they have reached the expected size for the variety in question, sound hollow when tapped, and when the curly tendril and leaf closest to the fruit begins to go yellow or brown.
This will typically be in late summer or early fall, but the time to harvest will vary depending on the variety, location, and conditions.
To harvest your ripe watermelons, simply twist or cut the stem to release the fruit from the vine.
Finally, for best results, remember that you should rotate your crops. You don’t want to grow watermelons in the same spot for multiple years. Move these around to different growing areas each year as part of your overall garden plans.
How many watermelons will one plant produce?
How many watermelons you get from a single plant will depend on the variety you have chosen, the conditions, and the location. But generally speaking, you can expect, if everything goes well, to get at least one and often two fruits per plant.
What are good companion plants for watermelons?
Watermelons typically need plenty of space. So, it is important not to introduce too much competition when deciding which other plants to grow close by.
However, it is also a good idea to think holistically when planning your garden and to grow plants close to your watermelon that will promote healthy growth and aid in tackling potential problems.
Beans or other legumes that fix nitrogen can be great companion plants since these fix nitrogen from the air with bacteria in their roots. Some of the nitrogen is used by the plants themselves, but some are made available in the soil, where it can be taken up by other plants nearby. Just make sure these don’t create shaded conditions for your watermelons, so position them carefully. You might place climbing beans on the same trellis as long as the watermelons still get plenty of sun. Alternatively, place bush beans or corn with beans climbing them on the north side of a watermelon patch (in the northern hemisphere).
Plant plenty of flowering plants that bloom around the time when watermelons require pollination. This will draw in those insect pollinators and also attract predatory insects like ladybugs, for example, that help control aphid populations.
Nasturtiums, in particular, are an excellent species to choose. They not only like similar growing conditions but also serve as a trap crop for aphids, cucumber beetles, and other pests. (They also provide edible yields in their own right.)
Radishes are another great trap crop for watermelon pests. They can provide a line of defense when placed around a watermelon bed.
Avoid planting watermelons only with other cucurbits, like squash, pumpkins, or zucchini. Since these share pests in common and will compete too much for space and resources.
How To Save Seeds
Unless you have grown seedless watermelons, saving the seed from your crop to plant next year is a very easy and straightforward process. (Just remember that F1 hybrids won’t come true from seed.)
First, remove the seeds from the ripe fruit. Then lay these in a single layer on a tray or kitchen paper to dry. Turn them over occasionally to promote drying.
Once the seeds have dried fully, they will be ready for storage.
Seed Storage Tips
After a couple of weeks, when the seeds have dried fully, place them into a paper envelope or paper bag and place them in a cool, dry, dark place until you sow them the following year.
Make sure you note the variety and date on the packets before you place them into storage. This allows for easy identification once the time for sowing rolls around.
Most often, troubles with watermelons arise because of:
- A lack of light.
- Insufficiently high temperatures.
- Garden soil conditions that are less than ideal. Meaning low fertility for these heavy feeders.
- A lack of water or waterlogging caused by poor drainage.
- Pollination problems.
Addressing any environmental issues and ensuring optimal growing conditions is always the first thing to look at if any problems arise.
As vine crops, you can certainly grow watermelons on a trellis or other form of support. As long as you make sure that the growing conditions are right and support the fruits as they swell and ripen.
Growing whole watermelons vertically is a great way to maximize the space available in your garden, especially when you don’t have a lot of room. It will allow you to grow watermelons in a much smaller area.
Restricting the growth of watermelon vines is generally not the best idea. When plants are allowed to grow naturally, they will generally produce fruit best.
However, you may sometimes cut back side shoots to focus the plant’s energy on main stems and fruit production. You may also sometimes selectively prune foliage and non-fruiting stems so more light can get through to ripening fruit.
No. watermelons are an annual crop that will have to be sown from seed each year. It completes its lifecycle within a single year.
Yes. You can choose seedless varieties of watermelon seeds to sow and grow at home. But you will also need to grow a seeded variety alongside them and ensure there are insect pollinators around in order to get seedless watermelon fruits.
Watermelons are a wonderful crop to grow in a garden where conditions allow. So if you live in an area with sufficiently high summer temperatures or can provide the right growing conditions in an undercover growing area, it is definitely worth giving it a go.
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