How To Grow Watermelons – Everything You Wanted to Know!


Everything You Wanted To Know About How To Grow Watermelons

…but were afraid to ask…  Now, what is a boiling hot summer day without chowing down on some cool, refreshing melons?  Doesn’t thinking about it make you want to become skilled at how to grow watermelons so you can have the most delicious ones on the planet at your fingertips?  There is nothing like it!

This low-calorie thirst and sweet-tooth quencher originated in the Kalahari Desert of Africa over 5,000 years ago, according to Hieroglyphics found in the region.

sliced watermelons


Watermelons Have Numerous Health Benefits

Here are some interesting facts:

  1. It has 50% more Lycopene than tomatoes.  Lycopene has antioxidant properties.  Therefore reducing the risk of stroke, and is used in prevention and treatment of some cancers and tumors.
  2. Containing L-citrulline, watermelon seems to relieve and protect against muscle pain and fatigue.  So, stick some in a juicer and drink it before a workout.
  3. L-citrulline, an amino acid, found in the red flesh, the rind, and the seeds, is good for your kidneys, promotes a healthy heart, treats Alzheimer’s disease, dementia, and high blood pressure.  It also is used to treat erectile dysfunction.  L-citrulline accomplishes all this by opening up the veins and arteries to improve blood flow.
  4. You can actually consume the rind and the seeds, too!  Stick the rind and seeds in a blender with a lemon or lime for a healthy, refreshing, hydrating drink.
  5. Technically, the watermelon is part vegetable and part fruit.  It is related to cucumbers, pumpkin, and squash…and it is a sweet, seed producing plant.


I Just Have to Plant a Few Hills of Watermelons Every Year!

Here, you can peruse a whole bunch of my favorite varieties!

NOTE:  If you choose to grow seedless watermelon, you will also need to grow a seeded variety, along with it.  Seedless watermelon plants are sterile.  A seeded watermelon plant must be close to them for pollination to occur.  And…guess what?  Without pollination, you won’t get any watermelons.


Planting Watermelons

When my Dad taught me how to grow watermelons, the most important thing I learned was to be gentle from beginning to end.

I start germinating watermelon seeds about 3 weeks before I plant.  When the seedlings pop out of the seeds, I transplant them into medium sized biodegradable containers.

NOTE:  Watermelon roots are damaged easily and may not transplant well if they are removed from a plastic pot so, it is vital to use biodegradable containers and plant the seedling, container and all, into the ground.

After the last frost, I start the hardening off process before planting them directly into the garden.

If I grow bush watermelon, such as the Bush Sugar Baby, I can find space in my backyard garden.  Their shorter vines are only 3 to 4 feet long.  Space them about 2 feet apart in the row, keeping 4 to 5 feet between the rows.  If you’re question is how to grow watermelon in containers, then, this bush watermelon or another small-sized variety would work.  Just pick a container 2 to 3 feet wide for each plant.

NOTE:  Bush watermelons only produce about 2 good watermelons per plant.


 My Choice…

The winner for me is a long vine, seeded watermelon variety, producing 2 to 4 first-rate watermelons per plant.
watermelons in a backyard garden

When these melons are in full growth mode, their vines can extend 20 feet or more!

Hence, I pick a special area in my yard to give them their own backyard garden plot and make hills for them to grow on.  The hills allow the soil to have better drainage.

In the early growth stages, prior to flowers forming, watermelons use a lot of nitrogen from the soil.  It is recommended to use a high nitrogen fertilizer at this time such as 33-0-0.  Then, as the vines begin to run, give the plants another dose of 33-0-0.

NOTE:  The fertilizer numbers indicate Nitrogen (N), Phosphorous (P), and Potassium (K)…as in N-P-K.  For example, 16-8-4 fertilizer contains 16% Nitrogen, 8% Phosphorous, and 4% Potassium.

Once the flowers start to form, the suggestion is switch to a fertilizer with high phosphorus and potassium content such as 5-20-20.

However, I always perform a soil test prior to planting.  And, I know that my N-P-K levels are within acceptable limits.  Consequently, I can use an all-purpose 10-10-10-fertilizer throughout the life of my watermelons’ growth and harvest.


 Watermelon Growth Summary

Watermelon Growth Stage Fertilize Water
Transplant the seedings into 6 inches high, 2 feet wide hills. Apply 2-3 tablespoons of high nitrogen fertilizer, such as 33-0-0, mixed with potting soil and dirt. Water well and keep the soil moist at all times.
The plants begin to grow vines. Apply a side dressing of high nitrogen fertilizer such as 33-0-0. Keep the soil moist at all times.
The plants begin to flower. Apply a side dressing of high phosphorus and high potassium fertilizer such as 5-20-20. Keep the soil moist at all times.
The melons begin to form. Apply a side dressing of high phosphorus and high potassium fertilizer such as 5-20-20. Keep the soil moist at all times.
The melons begin to ripen. If the plant does not appear healthy, apply a side dressing of high phosphorus and high potassium fertilizer such as 5-20-20.  Otherwise, leave it alone. Allow the top 1 to 2 inches of soil to dry out.


Making My Watermelon Hills…

I concoct a mixture of half potting soil, half dirt, and several tablespoons of fertilizer.  My hills are a half foot high and 1 to 2 feet wide.

I transplant 4 or 5 biodegradable containers of seedlings in each hill.  Water well and keep the soil moist but not soggy wet.  Watermelons love water.

Caution:  Too much water can cause disease and rot.

After the seedlings get a bit bigger in their new home on the hill, I thin out several of them, leaving 2 or 3 of the healthiest plants.

When watermelons begin to ripen, scale back the watering and allow the top several inches of soil to dry out.  This will drive more sweetness into the fruit.



Watermelons need only minimum pruning.  Using a sharp pair of shears or knife, cut off any dead, diseased, or pest-eaten leaves.  Remove any secondary vines that do not have flowers unless there are melons growing on them.  And, cut off any melons that show signs of rotting.

But, don’t start cutting on your plants when they are wet.  Because, it is way too easy to introduce disease sand parasites from one plant to the next if they are not dry.

After all this information, do you think you now know how to grow a watermelon successfully?  Then, let’s get to pickin’ a few…

Watermelon Harvest Time!

The key question is…how do I know when the watermelons are ripe???

“Thump” Technique

Rap a watermelon with a knuckle and listen for a hollow or a dull thump sound.  Sounds easy, right?  Well in the many years I have been knuckle-rapping melons, I usually have to pound a dozen or so, trying to guess which melon sounds the hollow-est.  Those poor melons…

Weight Test

Compare several watermelons of equal size.  The one that weighs the most is ripe the most.  But, is it really ripe and ready to be picked?  Duh…I don’t know…maybe it’s just a bit more developed but, still not ripe.

Visual Clues

Here are some much better gauges of watermelon ripeness:

Picking a ripe watermelon

The bottom of the watermelon…where it touches the ground while ripening will become a pale yellow color.  If it is not ripe, the color will be closer to white.  Even commercial watermelon farmers use this as a more reliable indicator.

The rind will be smooth and the top of the watermelon, will have a dull look, and not much contrast between the stripes.

The tendril closest to the fruit stem is withered and brown.  The fruit stem itself will also be drying out.


Use a Sharp Knife

Don’t twist, rip, pull, or mangle the fruit stem trying to remove a melon.  Use a sharp knife, scissors, or good quality garden shears like the Gonicc 8″ Pruning Shears, and cut it off cleanly to avoid damaging the vines.  Thus, saving the plant and possibly getting one or two more healthy melons.

sweet juicy cold watermelons


Now, there you have it!  A sweet, juicy ripe watermelon to stick in the fridge for a few hours of chilling before enjoying the most common summertime sport…spitting out watermelon seeds on a hot afternoon!



Pests and Diseases

Read my page on growing cucumbers, and you will find information on identity and eradication of the dreaded cucumber beetle.  Yep…they love watermelons, too!

Cucumber Beetle in a backyard garden

Squash vine borers also love watermelons.  The adults look a bit like wasps, mostly black with an orange-colored black-dotted thorax.  They lay their eggs around the plant, which turn into larvae that burrow into the stems of the plant.

These two are the worst culprits rendering damage to watermelon plants.

Outside of using floating row covers, the only vine borer defenses come from insecticides such as Sevin or Bacillus thuringiensis (or Bt).

Watermelons are pretty strong plants and defend themselves most handily against a number of diseases but, one that affects them the most is Powdery Mildew.  If your leaves start showing a powdery appearance, try some Neem oil to relieve the condition.


My Brother and Me

We sat on the back porch on the fourth of July…spitting watermelon seeds at each other.

Mom ran out, yelling, and made me cry…saying, “Don’t spit seeds on your brother!”

I said, “Mom, it’s not me.  I cannot lie.  It was the demon ghost of another.”

She said, “No matter how hard you really try, you can’t run THAT past your mother!”


Have you ever had your own “watermelon seed war” with a sibling?  Have you ever tried freeze-dried wagtermelon?  It is many times sweeter than fresh watermelon!  I’d like to hear from you in the comments below or by email:


Jim, the Life Long Gardener

4 thoughts on “How To Grow Watermelons – Everything You Wanted to Know!

  1. Chris Reply

    Hi Jim, Great article. I live in the cold and damp UK so a bit harder to grow watermelons here. Just have to buy them and eat them instead, though I’m sure they not as tasty. I didn’t know the roots were fragile. Always expected them to be tough and damage proof. Thanks for a good site and content. Best wishes, Chris

    • Jim Reply

      Hi Chris,

      Thanks, for visiting my website. Your cool “summer” weather must make it difficult to grow anything outdoors. But, you could think about constructing a green house which could increase your growing temperatures an additional 6 to 8 degrees Celsius. And, if you aren’t getting enough sunshine, grow lights would be a good option.

      Then even watermelon harvests could become a reality.


  2. Javier Weffer Reply

    Very informative post Jim. I did not know that watermelons were good for dementia I think that’s good news since my mother suffers from that disease. Besides having watermelon cut and small pieces and in juice there is another way that you would recommend perhaps mix with other fruit or veggie that it is good for dementia as well? and can you tell me of another farm products that are good for the disease?

    • Jim Post authorReply

      Hi Javier,

      Other garden plants that help decrease dementia include: Nuts (especially Walnuts), Beans (Lentils and Chickpeas are high on the list.), Broccoli, Cauliflower, Brussels Sprouts, Blueberries, Whole Grains (Like Oats, Brown Rice, and Whole Grain Wheat), and Olive Oil.

      These veggies and fruits are especially helpful in early stages of dementia.

      Hope my suggestions help your mother.


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