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Can Watermelons Get Too Much Water – How Much Is Enough?

Watermelons are an enjoyable and yummy summertime fruit. I think they are some of the easiest fruits to grow and so worth it. Watermelons are known for their water content. 90 percent of the fruit is water, making it the fruit with the highest water content. Naturally, you would think this would mean that you have to water it a lot when growing watermelon. Yes, you should give watermelons a lot of water, but can watermelons get too much water?

Watermelons can get too much water. Generally, they need about one to two inches of water a week, and that amount should be tapered off as the fruit grows. Too much water can cause things like rot and diseases, and it can even cause the fruit to burst. 

To learn more about how to water watermelons, the diseases that happen when there’s too much water, and more, stick around! 

What Happens When Watermelons Get Too Much Water?

A handful of things can happen to watermelons when they get waterlogged. Let’s take a look. 

Exploding Melons

When watermelons get an excess of water, it causes the fruit to swell because it can’t hold all of that extra liquid. This will cause the rind of the watermelon to rupture and burst. This usually happens later in the fruiting stage, when the melon is practically ready for harvest. This is very similar to when a tomato faces overwatering; the skin of the tomato starts to crack and “explode.” 

White Hearts

White hearts is a term for the flesh of the melon looking very pale and almost white. This happens when there is an excess of water, and the fruit grows faster than sugar production. The watermelons will often look very large when this happens, but the inside looks pale, and the overall flavor is very dull and flavorless. This also happens later in the fruiting stage.

Root Rot

Root rot can happen at any stage of a watermelon plant’s life. It also can happen to any plant or vegetable. Roots saturated with too much water can get fungal infections and begin to rot. This will cause the plant to look wilted and leaves browning. Eventually, the plant will die. 

Leaf Disease

Leaf diseases like powdery mildew and leaf spots will occur when a plant gets too much water on its leaves and there isn’t time to dry off. These are considered fungal infections of the leaves and can happen at any point in the plant’s life and can happen to any plant or vegetable.

A bad leaf infection will cause the leaves to look brown, eventually dying and falling off, which, in turn, will affect the plant’s ability to photosynthesize, and the overall harvest may be affected. 

How To Prevent These Overwater Issues

Thankfully, these issues caused by overwatering can be prevented and, in some cases, reversed if you are lucky and give your plants a little extra TLC. 

Preventing White Hearts and Exploding Melons

  • White hearts and exploding melons can very easily be avoided. However, because it happens so late in the melons stage and you don’t normally notice these things until it’s too late, there is no reversing these issues. You can water a watermelon one to two inches a week until a little over a week of their harvest. When the melon reaches full size, you can stop watering the plants altogether. This will allow for the melon to become sweeter, and you won’t risk issues of white hearts and exploding melons. 

Preventing Root Rot 

Root rot can be prevented, and depending on when you caught the issue; you may be in okay shape to save your plant or its fruit. If root rot begins to show signs in the early stages of growth, allow your plant to dry out for a few days.

You can also put some sulfur around the plant to soak into the roots to try and kill off any infections. This is not a guaranteed fix, but it is worth the try. If this happens in the later stages, where there is already fruit growing, you can let your plant dry out again or harvest even if it’s a little early.

This issue can be prevented by making sure you stick to a good watering schedule, and you don’t water more than two inches a week. Try just watering every other day; if it’s extremely hot (95 plus), water every day, and water early in the morning to allow the soil to dry during the day.

Preventing Leaf Diseases 

Luckily, powdery mildew is a very mellow disease and won’t do too much damage; however, if left untreated, it can spread onto your watermelons if they have begun fruiting, making them inedible. Powdery mildew is both preventable and reversible. Powdery mildew will look like white mold growing all over your leaves.

Once you see this, try spraying your leaves with a 1:1 ratio of vinegar and water. This is usually pretty much all you need to do, sometimes only once. The same rules apply to leaf spots. Both diseases can be prevented by watering your watermelons the proper way.

Watermelons do not need overhead soaks; they thrive much better by getting direct water to the roots. This way, the water is going exactly where it needs to go, and you can prevent infections. 

The Proper Way to Water Watermelons 

Just above, I mentioned that watermelons do not need overhead water. This means that the water should go directly into their root systems when you water. There are a few methods you can try. 

Hand WaterIf you only have a few plants,
hand water from your hose
that has a good hose head, is the
best and most efficient way to water.
Water your watermelons everyday for about
30 seconds to ensure they are getting
1-2 inches of water a week.
Dripline IrrigationDrip line is the best way to water your crops
if you have many watermelon plants down
in a row. By turning on and off the valve,
you can regulate how much water is getting
to your plants and you know that the water
is going directly on to their roots. The only
downfall to drip irrigation is that setting it up
tends to get a little pricey, so it’s really only
worth it if you have a larger field of plants.
Bubbler Water SystemA bubbler water system is a great and simple
way to water, if you don’t want to hand water 
and have more than one or two plants. Simply
just connect it to your hose and turn it on
for 5-10 minutes every other day to get water 
to your plants roots. 
Different ways to water watermelons

Watermelon Watering Tip

If you live in a very dry and hot climate during the summer months, it can be tricky to keep your soil moist but not overwater. Putting mulch down around your plants is an excellent way to ensure that the soil stays cold and moist.

With mulch, you also know you won’t need to water your plants more than once every other day, even when it’s hot and dry. When it’s time to stop watering your watermelons, you can decide to remove this mulch to help with the process.

Final Thoughts

Watermelons are a very watery fruit. With 90 percent of them being made up of water, it is important to keep watermelon plants watered. Although it is possible to overwater them, the damages done from overwater can be easily prevented. Happy gardening!