The watermelon is a tender, warm-weather annual. Watermelons along with muskmelons and cantaloupes are sometimes called summer melons. Grow watermelons in the warmest, frost-free time of the year.
- Sow watermelon seed in the garden or set out transplants 3 to 4 weeks after the last average frost date in spring.
- Start watermelon seed indoors about 6 weeks before transplanting seedlings into the garden. Start seed indoors in 4-inch or larger biodegradable peat or paper pots that can be set wholly into the garden so as not to disturb the roots.
- Watermelons require 65 to 90 frost-free days to reach harvest.
Where to Plant Watermelons
- Plant watermelons in full sun.
- Watermelons grow best in loose, well-drained, but moisture-retentive soil rich in organic matter.
- Add aged compost and aged manure or a commercial organic planting mix to the planting bed before planting. Turn the soil to 12 inches deep.
- Melons prefer a soil pH of 6.0 to 6.8.
- Plant watermelons on hills or mounds or on raised rows. Solar heat hitting the soil on a mound or raised row will keep plants and roots warm.
- Create a mound 6 to 12 inches high and 5 feet across.
- If planting in ground-level beds, warm the soil in advance of planting by laying black plastic sheeting on the bed two weeks before planting.
Watermelon seed will germinate in about 10 days at 65°F, sooner in warmer soil.
Watermelon Planting Time
- Sow watermelon seed in the garden or set out transplants 2 to 3 weeks after the last average frost date in spring.
- Garden soil temperature should be at least 70°F at planting time. Pre-warm the soil by placing black plastic sheeting over the planting bed for two weeks prior to planting.
- To get a head start on the season and in short growing season regions, start watermelon seed indoors about 6 weeks before transplanting seedlings into the garden; start seed in biodegradable peat or paper pots at least 4 inches in diameter that can be set wholly into the garden so as not to disturb roots.
- Watermelon seed will germinate in about 10 days at 65°F, sooner in warmer soil.
- Watermelons grow best in air temperatures ranging from 70° to 90°F.
- Avoid growing watermelon where night temperatures dip below 50°F; this will cause the fruit to lose flavor.
- If temperatures exceed 90°F for several days, flowers will drop without setting fruit.
- Watermelons require 65 to 90 frost-free days to reach harvest depending on the variety.
- Watermelons will tolerate no frost. In cool or short-season regions, grow smaller varieties that come to harvest quickly.
Sow watermelon seed in the garden or set out transplants 3 to 4 weeks after the last average frost date in spring. Start watermelon seed indoors about 6 weeks before transplanting
Planting and Spacing Watermelons
- Sow watermelon seed 1 inch deep.
- Sow 4 to 6 melon seeds on a mound or hill.
- Germination will occur in about 10 days when the soil is 70°F
- Thin to 2 or 3 strong seedlings on each hill when seedlings have developed three or four true leaves. Cut the thinned seedlings at soil level with scissors so as not to disturb the roots of the remaining seedlings.
- Space mounds or hills 5 to 6 feet apart.
- Mounds can range in height from a few inches to more than 12 inches tall; mounds will allow vines to run away down the slope. You can train vines to circle the mound.
- If you are growing watermelon in rows space plants 4 to 5 feet apart and space rows 6 feet apart.
- Grow 2 watermelon plants for each household member.
More tips: Watermelon Seed Starting Tips.
Support melons growing on a trellis with netting.
Growing Watermelons Vertically
- Watermelons can be grown up a trellis.
- Use a trellis at least 8 x 8 feet wide or wider. Make sure the trellis is well-anchored.
- Space plant at the base of the trellis 3 to 4 feet apart.
- Train vines up the trellis; secure the vines to the trellis with elastic garden tape.
- Support melons growing the trellis with netting.
- You can also grow watermelons on an A-frame trellis. Lean two trellises together, tie them at the top and anchor the base of each trellis.
Container Growing Watermelons
- Watermelons are usually too large to grow in a container.
- Select a bush, dwarf- or mini-cultivar to grow in a container.
- Chose a container that is at least 18 inches wide and deep to grow one watermelon.
- In short growing season, regions extend the season by starting melons in containers indoors; move them outdoors when the weather has warmed but be careful not to pinch or break the vines.
Watering Watermelons
- Watermelons are 95 percent water. They require plentiful regular, even watering for quick growing.
- Give watermelons 1 to 2 inches of water every week (1 inch equals 16 gallons.)
- Keep the soil moist until fruit reaches full size then stop watering while the fruit ripens.
- Mulch to retain soil moisture. Spread straw or dried chopped leaves around watermelon plants after the soil has warmed. You can also lay black plastic sheeting or garden fabric across the planting bed. Cut an x-slot in the fabric to plant.
- Water at the base of plants with a soaker hose or drip irrigation. Wetting the foliage will leave plants susceptible to fungal diseases such as powdery or downy mildew.
- Keep the soil evenly moist during flowering and fruit development. A week or so before harvest cut back on water; dry soil will help plants concentrate sugars in the fruit.
- If leaves are wilted in the morning, the plants need water. Wilting leaves at the end of the day is not uncommon.
Feeding Watermelons
- Prepare planting beds with aged compost and aged manure or a commercial organic planting mix. Turn the soil to 12 inches deep.
- Add several inches of aged manure across planting beds the autumn before planting.
- Side dress watermelons with compost or manure tea or a dilute solution of fish emulsion every 2 to 3 weeks during the growing season.
- Watermelons can be side dressed with an even organic fertilizer such as 10-10-10 early in the season but once flowers and fruit appear, reduce nitrogen and increase phosphorus and potassium; use a 5-10-10 fertilizer.
Companion Plants for Watermelons
- Plant watermelons with corn, radish, beans, and nasturtiums.
Watermelon Pollination
- Watermelon plants produce both male and female flowers.
- Male flowers appear a week or two in advance of the female flowers. Male flowers attract bees that are needed for pollination once female flowers appear.
- Female flowers will have a small bulge at the stem end of the flower. This bulge is an embryonic fruit.
- Some male flowers will die and drop before female flowers set fruit.
- You can hand pollinate watermelon flowers using an artist’s bristle brush. Rub the brush in the male flower to collect pollen then rub the brush in the center of the female flower to transfer the pollen.
- You can attract bees to your garden by planting flowering herbs such as dill, borage, and lavender nearby.
Set the growing watermelon on a tile or wood. This will keep the melon off the ground and help it stay warm,
Caring for Watermelons
- Early in the season cover plants with a floating row cover. This will keep insects away and hold warm air around plants. Once plants begin to flower, remove the row cover during the day so that bees can get to the flowers.
- Encourage watermelon plants to set three or four fruits at the same time; if a plant sets one fruit early, pinch it out to encourage the plant to develop several fruits at the same time. One fruit off to a head start can suppress all further fruiting on the vine until that fruit matures.
- Cultivate carefully around vines until they cover the ground and smother out competing weeds.
- Mulch around watermelons with straw, dry chopped leaves or set down black plastic or garden fabric. Mulch will keep down weeds and conserve soil moisture.
- For sprawling watermelons, place a tile, wooden shingle, or a piece of plastic under each melon to keep the fruit clean and dry and to store solar heat which will help ripen fruit.
- About 50 days before the first expected autumn frost, remove all new blossoms from a plant; this will allow the plant to concentrate its energy into the development and ripening of fruit already on the plant.
More tips: How to Grow Watermelon for Best Flavor.
Watermelon Pests
- Aphids and spotted and striped cucumber beetles will attack melons.
- Hose away aphids with a blast of water or pinch out infested foliage.
- Hand-pick and destroy cucumber beetles promptly; they can transmit cucumber bacterial wilt to melons. You can also control cucumber beetles by spraying insecticidal soap, neem oil, or dusting with kaolin.
More tips: Melon Growing Problems: Troubleshooting.
Watermelon Diseases
- Watermelons are susceptible to anthracnose, altenaria leaf spot, bacterial wilt, and powdery and downy mildew.
- Planting disease-resistant varieties when they are available and maintaining the general cleanliness and health of your garden will help cut down the incidence of disease.
- Do not handle the vines when they are wet; this can spread fungal diseases.
- If a plant does become infected remove it before it can spread the disease to healthy plants.
- Bacterial wilt which is spread by cucumber beetles can cause watermelon plants to suddenly wilt and die just as they begin to produce fruit. Control cucumber beetles as soon as they appear.
- Anthracnose is a soil-borne fungal disease that can cause leaf spots, leaf drop, wilting and sometimes death. Keep the garden clean and plant disease-resistant varieties. Remove diseased plants from the garden immediately.
- Powdery mildew and other fungal diseases can be prevented and slowed by spray-misting plants with compost tea or a solution of 1 part skim milk and 9 parts water.
Limit water for a week in advance of the harvest to concentrate sweetness.
Harvesting Watermelons
- Watermelons will be ready for harvest 65 to 90 days after sowing depending on the variety.
- When watermelons are ready to harvest vine tendrils will begin to turn brown and die off. If the tendrils are green the melon is not ripe.
- A ripe watermelon will make a dull hollow sound when thumped.
- The soil-side of a watermelon will turn from white to pale yellow when the fruit is ready for harvest.
- Ripe melons will have a sweet aroma at the stem end.
- Limit water for a week in advance of the harvest to concentrate sweetness.
- Watermelons on a single plant will all be ready for harvest over a two week period.
- Use a sharp knife or garden pruner to cut the watermelon away from the vine.
- Watermelons do not continue to ripen off the vine.
Storing and Preserving Watermelons
- Watermelons will keep in the refrigerator for up to a week if not cut or sliced, but sweetness and flavor may diminish.
- A cut watermelon will keep in the refrigerator for about 4 days. Wrap the melon tightly in plastic to prevent cold burn or dehydration.
- It takes about 12 hours to chill a large watermelon.
- Watermelons can be kept in a cool, moderately moist place for 2 to 3 weeks without refrigeration.
- Melon flesh can be frozen and rinds can be pickled.
More tips: How to Harvest and Store Watermelon.
Watermelon Varieties to Grow
- Icebox size watermelons: ‘Early Midget’ (65 days); ‘Garden Baby’ (70 days); ‘Golden Midget’ (65 days); ‘Sugar Baby’ (68-96 days); ‘Tiger Baby’ (80 days).
- Oblong, green rind: ‘Northern Sweet’ (68 days).
- Oblong, grayish rind: ‘Allsweet’ (100 days); ‘Calsweet’ (92 days); ‘Charleston Gray’ (90 days); ‘Desert Storm’ (80 days); ‘Fiesta’ (85 days); ‘Regency’ (82 days); ‘Royal Majesty’ (80 days); ‘Sangria’ (85 days); ‘Strawberry’ (85 days); ‘Sun Sweet’ (85 days); ‘Sweet Favorite’ (64-79 days).
- Round, green: ‘Black Diamond’ (75-95 days); ‘Black Diamond Yellow Belly’ (90 days); ‘King and Queen’ (80-90 days); ‘Moon and Stars’ (100 days).
- Round, striped: ‘Crimson Sweet’ (80-96 days); ‘Navajo Sweet’ (90 days); ‘Super Sweet’ (90 days).
- Giant-sized: ‘Carolina Cross’ (100 days).
- Space savers: ‘Bush Sugar Baby’ (80 days); ‘Garden Baby’ (75 days); ‘Petite Sweet’ (75 days); ‘New Hampshire Midget’ (77 days); ‘Sugar Baby’ (79 days).
- Yellow or orange flesh: ‘Arikara’ (85 days); ‘Yellow Doll’ (75 days).
More varieties to grow: Watermelons for Home Gardens: Top 12 Varieties.
About Watermelons
- The watermelon is a long-trailing annual plant.
- Watermelons can be solid green or striped green and white.
- Watermelons can be oval, oblong, and round.
- Fruits can weigh from 10 or 15 pounds to more than 100 pounds. Fruits are commonly 30 pounds or more.
- The watermelon has a thick, solid rind with sweet, succulent flesh that can be pink, red, yellow, orange, or grayish-white.
- Male and female flowers appear on the same vine.
- Botanical name: Citrullus vulgaris
- Origin: Tropical Africa
We are interesting in buying Black Diamond Watermelon’s Wholesales next season for resale.
Please give some tips for growing watermelon. I live in the tropical country of Fiji.
Growing Watermelon: Watermelon originated in tropical Africa. Small, round watermelons can be successfully grown in cooler short-season regions, large oblong watermelons up to 50 pounds can be grown in tropical regions. Watermelons do best where the seaon is warm and long. Direct seed 5-6 seeds in mounded hills spaced 6-8 feet apart; direct sow 4 weeks after the last frost. When the plants emerge thin to the best 2 plants in each hill. (For those growing in frost areas, sow seeds indoors 3-4 weeks before the last spring frost in 3-inch pots for transplanting out when temperatures warm to 75F.) Watermelon prefers rich, light, well-drained soil–so dig in plenty of compost before sowing or transplanting. Side-dress watermelons with dried manure or organic fertilizer when they are still upright, before they sprawl. Make sure the plants get 1 inch of water every week, but don’t overwater. If you are in a rainy region, be sure the plants are set on high well-drained hills. Be consistent in watering. Reduce water 4 weeks before harvest when melons are about two-thirds mature size. Watermelons grow best where the day temperatures are between 70F and 90F and where night temps do not fall below 60F.
Thanks for your useful comments on growing Watermelons. I was told by someone not to transplant watermelons and grow them directly in the final location.
I am in Dubai and summer temperatures are regularly 40 to 50 degrees Centigrade. I planted 10 seeds in February and I have around 5 plants. Now in Mid June – I have one fruit that was the first one (appeared in early May) and it just stopped growing. Its not growing in size though it looks green and healthy. I have another fruit that is growing very well and is like a smallish football now (Appeared at end of May).
Q1: When is the best time to pick the fruit? How do I know that it is ripe?
Q2: There are still female flowers coming on some of the plants. I am pollinating these using the male flowers. But will these grow into good fruits – now that we are in June (Full summer).
This is my first garden – just had it laid end of Dec 2010 and I am experimenting with several different plants. I did well with Tomatoes in Feb and March and I had Aubergines at the same time.
Q3: What other fruits/ veg will be suitable for Dubai weather (particularly in the HOT Summer months)?
Dear Mr Moosa
Hi,
I am producing several crops in large scale in a country by the same weather condition. You can easily plant Watermelon, Abusabaein, Maize,Sweet corn, Sesame,Muskmelon, Different other crops
Just you should adjust the best time of planting for different crops.
Does watermelon grow wel together with maize
How many Black Diamond watermelons grow per plant? Some of my tiny watermelons are turning completely black. Would you happen to know why?
Thanks,
Rhonda
A watermelon can set as many fruits as there are flowers; however, too many fruits will stress the plant resulting in some fruits failing. Allow the plant to set just two fruits; nip away flowers that appear after you have selected the two fruits you want to mature.
Is it possible to grow Watermelons outdoors in the north of England? We get plenty of rain, but not so much sun!
I have been growing watermelons in my greenhouse, this is my first time growing them. One of the vines seems to be dying; it’s leaves go yellow in spots, then brown and wilt and the stem is doing the same. Does anyone know what could cause this? The other two plants nearby are showing the same symptoms but not as badly-any chance I can save them? I prefer organic gardening if possible, but would welcome any recommendations. As these are the only three plants I have I really don’t want to destroy them all. Many thanks.
Merry
Watermelons and other melons grow best in full sun in rich, loose, warm soil, soil no cooler than 60F. Keep the soil warm by covering it with black plastic. Depending upon the cultivar, your watermelons will need 85 to 110 days of warm weather to reach harvest. Plant your watermelons in the warmest part of your garden, perhaps near a wall, fence, or building where it will receive reflected heat. Try growing a small, quick-to-harvest variety: Cole’s Early, Garden Baby, Sugar Baby, Sunshine, Yellow Baby, or Yellow Doll. Given the rainy situation, you might try growing your watermelons under plastic tunnels; you will protect them from the rain and trap solar heat at the same time.
Melon leaves that turn brown and wilt may have angular leaf spot, anthracnose, or Alternaria blight. Angular leaf spot, a bacterial disease, starts with water-soaked spots on leaves and stems; a bacterial ooze will follow on leaf undersides. Prune off infected leaves and stems; spray with copper to slow the spread of disease. Anthracnose, a fungal disease, can start as yellow water-soaked spots on melons; leaves turn brown. Spraying with sulfur can help slow the spread of this disease. Alternaria blight, a fungal disease, causes concentric rings on melon leaves, leaves yellow an die. Remove leaves from infected plants; spray plants with a baking soda solution or compost tea. These diseases can be slowed by irrigating at the base of plant stems, not overhead. Allow plant foliage to dry each day. If your plants die, you will want to thoroughly clean the greenhouse or planting bed; remove all crop debris to be rid of any remnants of the problem. Plant so that there is plenty of air circulation around plants. Choose disease resistant seed or starts for planting.
Vegetable gardening in hot summer regions calls for a shift of your growing season. Grow your warm-season crops so that they come to maturity before average daytime temperatures exceed 90F. This will mean planting and growing your crops earlier and later to avoid the hottest time of the year–when vegetables can not grow. You may want to choose cultivars that are quick maturing (see the Quick-growing list in the Topics Index) to get your crops in between very cool and very warm seasons. Also check the Hot Weather Garden topics index for articles on using shade, water, and mulch to grow vegetables in very hot weather. Hot region vegetable gardens can be grown in sunken beds–beds dug below the soil level; these beds will be cooler, closer to ground water and more easily shaded with shade cloth set over a frame. When temperatures are above 90F, expect crops to stop growing–they will wait until temperatures decline to resume growing, provided they don’t become too stressed and die.
Water melons growing on pavement https://www.youtube.com/watch?v=eOER24yKWo4
Ni elim nzuri
Asante (thank you) — yako kuwakaribisha (your welcome). Thanks for reading Harvest to Table!
i have grown water melon but what fertilizers to be applied coz they are two weeks now and how can i get high yields. thanks
Watermelons and other melons do best in loose, rich soil. Add plenty of aged compost to the planting beds–before you plant and as a side dressing once plants are growing. You can never add too much aged compost to a planting bed. If you want to use a store-bought fertilizer, choose an organic or natural fertilizer that is low in nitrogen and high in phosphorus and potassium. Follow the directions on the label. Choose the strongest vines and allow two or three watermelons per vine to mature. Be sure to keep the soil consistently moist for uninterrupted growth.
what about fertigation? Please give details about fertigation of water melon.
Watermelon–like other fruiting vegetables–is best fertilized with a low nitrogen–higher phosphorus and potassium fertilizer. for example 5-10-10. Fertigation systems inject fertilizer into the irrigation lines–these systems use liquid fertiizers or water soluble powder fertilizers (made into a liquid before placing into the fertigation system). Fertigation systems commonly come with instruction sheets to help you set the flow of fertilizer into the system. Instruction sheets from each manufacturer should give you suggested mix and flow for each crop.
fantastic piece
Thanks for reading Harvest to Table!
First-timer question: How can I protect my growing watermelons from critters? I have lots of squirrels and birds, plus the occasional possum, raccoon, and fox (and the neighbor’s stupid cat). How much light and air does the actual melon need? I’m growing Crimson Sweet in SW Missouri.
Your watermelons will benefit from plenty of sunshine and good air circulation. Plant in full sun and, if possible, where there is a gentle breeze. Bird netting will keep birds from visiting the garden–and that may keep the neighbor’s cat at home. You can also spray your vines with a garlic-based spray repellent. You can get an animal repellent at the garden shop or make your own: use several cloves of garlic in a quart of water, whirled in a blender, strain to remove solids, add a drop of liquid dish soap as a spreader-sticker, and spray the plants.
First time grower: My watermelon are planted in my pool area since water is always plentiful through the season and they are doing well. My question though: I have three vines that have made it to the concrete around my pool and are heading for the water. They have three fruits growing. Will the watermelon sustain on concrete that is daily too hot for my feet? 125F+ They look to be doing fine.
You can direct the watermelon vines away from the concrete and back into the planting beds. The vines themselves are simply growing–not actually heading for the pool. Keep the soil moist around the stem and roots of the plant while fruit is developing. Yes, the concrete may get so hot that the moisture in the melon–watermelons are 90 percent water–can heat up and crack the fruit. So best to let the melons develop in the garden–on top of a patch of straw.
I Want To Plant A Half An Acre Of Watermelon, Can 500g Type F1 Sukari Seed Be Enough, And Can It Do Well In A Heavy Rain
Grow 1600 to 1800 watermelons per acre. There will be 3000 to 5000 watermelon seed in 500 grams. Plant watermelon in well-drained soil. Keep the soil evenly moist. Excess water will dilute the flavor of watermelon.
Hello Good Day,
Some body told me that if I want my Watermelon fruits to be Bigger and more sweet, I should cut up the end of the vines and put it in the ground,
then I should pour suger on it’s roots
Pls. did you know something like this?
Thanks a lot
This method is not familiar. Perhaps some readers can help. Watermelons grow best in light, humus-rich soil that is deep and well-drained. A pH of 5.5 to 6.5 is preferred. Add aged compost or commercial organic planting mix to at least 8 inches deep. Aged manure added several months in advance is also helpful. Add rock phosphate to the planting hole in spring. Harvest then the underside of the melon turns from white to yellow and at least three tendrils on each side of the melon are dead.
How Frequently Do I Need To Water
Keep the soil evenly moist; do not let it dry out. The frequency of watering will depend on air and soil temperature. If your temps are in the 90s, you will likely need to do a deep watering every 7 to 10 days, a shallow watering every 5 days. Check the soil at 6 inches deep to be sure it is just moist–not dry.
Why are my melons splitting before there ripe?
Melon split when water uptake is erratic–the soil goes dry, then heavy watering follows. Plant cells burst when the uptake of water is heavy and quick.
Hello Steve,
My plants finally have watermelons but I am encountering a problem. We don’t have any bees and therefore, I have to self pollinate. I use about 5 or 6 male flowers but after about a couple of days, the baby melons seem to be turning yellow. Some female melons have also turned yellow before the flowers even open. I fertilize weekly with fish fertilizer and also have used a side dressing of 5-10-10 morcrop. Can you please give me some advice? I really want my melons to grow. 🙁
Be careful not to overfertilize. If you have side dressed with MorCrop you can hold off on the fish emulsion until fruit begins to grow. The failure of the flowers and fruits is likely the result of poor pollination. If temps are greater than 87F, the pollen may be dying before it pollinates the female flower. If temps are very hot; shade the flowers when you hand pollinate.
Hi. Can you please advise as to why watermelon turn yellow before their flowers even open and how do I grow successful watermelon through hand pollination? It’s like the melons don’t take the pollen and turn yellow and die a few days later. Pollination is used by hand with a lot of flowers on the female. How do I get these melons to grow please?
There are a few reasons pollination fails–this time of year it is usually daytime temperatures being greater than 87F. If temperatures are very warm, wait until they moderate to try hand pollination again.
I live in Denver Colorado and was given some pink Navajo watermelon plants off the reservation. Questions: I have a 4′ x 4′ spot for one to grow and it is out growing the space. I have more flowers than I can count both male and female. How do you know when they are pollinated? Do remove vines before or after I see fruit? Is it OK to have the vines lay over each other?
If possible train the vines so that they do not overlap; try to train to circle the center of the plant. When pollination occurs, the small embryo fruit at the base of the female flower will begin to swell and grow. If pollination does not occur the female flower will wither and die. Once the plant has begun to develop two or three melons, you can clip the growth tips of the vines and remove new flowers.
Can someone please tell me why all of my baby watermelon are turning yellow and rotting days later after the flowers close? Self pollination doesn’t seem to be working but I know something else is causing this. Should I water every 3 or 4 days instead of every day? I highly doubt I will have any success with this growing process of rotting melons.
Watermelon flowers and young fruits can die for a few reasons: (1) uneven soil moisture, soil sometimes dry; keep the soil evenly moist; do not let it go dry; (2) insufficient pollination; the flowers were not fully pollinated and so they aborted; you can hand pollinate; (3) the daytime temperatures are too high; temperatures greater than 87F can cause plant stress; to survive the plant will abort flowers and fruit. If temps are high; wait for them to moderate. Feed the plant a dilute solution of fish emulsion every 10 days. Do not let the melons sit on the ground; once they for, place a tile or board underneath them to keep them from coming in contact with soilborne diseases.