How to grow watermelon


Today in Gardenprue we are going to know a general idea of ​​the cultivation of watermelon for anyone who wants to leave a hole in their garden  for this cucurbit. Here we will deal with the main points of the development of the plant, with tips and techniques to achieve a good performance of the watermelon. Do not leave aside this impressive fruit that we all love when the temperatures rise.


As we have mentioned before, it is a cucurbit and has its origin in Africa. Its scientific name is Citrullus lanatus  and it has different names  throughout the planet: water melon, aguamelón, pin, paitilla, etc.

Watermelon, in terms of its morphology, is very similar to melon . It has a main root that can go deep enough, and its stems, which can extend between 2 and 3 meters long, are creeping and have hairs.

Ah! I don’t know if you’ve ever wondered why we put watermelon as a fruit, when many people introduce it into vegetables.

It turns out that you can tend to name the watermelon as a vegetable because it belongs to the Cucurbitaceae, such as cucumber, pumpkin, zucchini, melon, etc. But in reality, if we base ourselves on the definition of fruit, it refers to all edible fruit, with sweet or acid properties that are mostly consumed as dessert. 

And since it is like that in Spain, we classify it as fruit.


Watermelon is a plant that requires high temperature conditions. In order for it to germinate, and do it well, the temperature of the environment in the watermelon crop must be between 21 and 35º C (from 15ºC it can start, or at least, it is the theoretical minimum.).

Once it has germinated and is in the growth stage, the optimum development temperature is between 21 and 30 ºC. Be careful with temperatures above 35 ºC, in which we will have to provide extra risks.

From these easily achievable values ​​in summer, the watermelon plant begins to perspire and loses a lot of water through evaporation, quickly entering a water stress that we will have to solve by providing irrigation water easily assimilated by its roots.

When weather conditions do not allow the watermelon to accumulate hours of heat, the crop is usually mulched or formed in greenhouses. Plastic padding is very common.

Watermelon padding with rind. Photo by Michele Dorsey Walfred


Watermelons are usually harvested 80-100 days after planting. Harvesting is carried out when common characteristics appear such as the hollow sound of the fruit, the appearance of a yellow color in the lower part of the fruit, easy peeling with the nail, etc.

Choice of plot

The plot where it is cultivated must have the following characteristics:

  • Good drainage.
  • No slope.
  • No weeds.
  • No herbicide residues.
  • No  harmful nematodes and insects.


deep work must be done , since as we have mentioned before, watermelon has a very deep main root.

Watermelon is very susceptible to weed growth and does not take herbicide treatments very well. Black polyethylene padding is generally available, with its environmental drawbacks. In the case that it is grown in small quantities in the garden, weed cleaning can be done manually.

Pruning is not usually done . Deformed or rotten fruits are simply removed. In exceptional cases, if the branch extends outside the crop line, the tips are removed.

When it comes to fertilizing , if you have arranged the watermelons in your garden, it is best to follow the basics of organic farming. Organic and natural fertilizers such as compost or manure go very well to the crop if they are added as a background one month before transplanting. This is why the deep bed works so well.


You have two options when planting, either you sow the seeds indoors with controlled temperatures and later transplant when the seedling has at least several true leaves, or you sow directly in your garden. Everything will depend on the weather of course, but you have to take into account the following:

The watermelon seed does not have a very high germination power , although it will depend mainly on the type of seed it is (the most modern ones have no problem).

Watermelon fruiting. Photo by Kim Siever

It is best to introduce several seeds, around 3, for each planting hole. Do not worry if 1, 2 or 3 comes out later, because you will take care of making a ringing  (see the link if you do not know what it is about).

It is advisable to place them in a hole no more than 3 centimeters deep, in the final garden (if you protect it from the cold), or in seedlings or preparatory containers with a mixture of soil, sand and compost. 

Here you have an option to get down to work with the acquisition of watermelon seeds .


Watermelon does very well in medium-textured or silty soils. In addition, the soil must have good drainage capacity, because the plant is susceptible to waterlogging and Fusarium.

The growth pH of the culture is slightly acidic and is between 5 and 6.8.

Its resistance to salinity is classified as sensibly moderate . An excess of salt in the soil induces problems in the development and a decrease in the size of its fruits.


Watermelon can grow in dry land, but its ideal condition is irrigated . The greatest water needs are required from flowering until fruit growth ends.

Once this period is over, irrigation control is very important in watermelon cultivation, which must be constant to avoid cracking or cracking.

Some sources indicate that a progressive reduction of the irrigation flow when the fruit growth ends increases the sugar content in the watermelon.

The moisture status of the soil around the watermelon is observed. Source: Wikimedia commons


There is less and less tendency to irrigate a blanket , as was done in the past. Although it is a good irrigation method that achieves great uniformity, it has a very high cost and so much water is wasted that today it cannot be allowed. One of the most important substitutes is automatic drip irrigation .

Follow the following tips to avoid getting lost with the risks:

  1. Before sowing or planting:  just before sowing our watermelon seedlings it is convenient to wet the soil in depth. This will reduce transplant stress and keep humidity levels adequate. What was said. Abundant watering is required.
  2. After the transplant:  once the transplant has been done, we can give a light watering in order to settle the plant. Remember that it should not be excessive since the soil already retains enough moisture from the previous irrigation.
  3. Subsequent irrigation: at this point we will follow the previous advice. Maintain an adequate level of humidity in the soil, without flooding but ensuring that there is always water availability through the roots. This is not allowing the soil to become dry or caked.

In short, to be able to harvest large and juicy watermelons it is essential that there is constant humidity throughout the plant’s growth process, and once it is the size we want and is in the middle of the ripening process, regulate and reduce watering. to increase the concentration of sugars.


Anyone experimenting in the cultivation of watermelons will know the importance of pollinating its flowers to obtain magnificent productions. Although we will not ask you to have your own hive, but you do take care of the environment that surrounds your garden. We have an article especially suitable for this, in which we talk about garden animals. 

Watermelon pollination can be done by different insects. The most common is that it is done by bees but also bumblebees perform their function.

Ultimately, an environment with vegetation, a well-kept garden, with access to water (as it could be with the construction of a pond ) will ensure a high density of beneficial insects and a successful pollination of your watermelons.

Photo the Kim Siever


In the cultivation of watermelon, varieties of vigorous plants are sought, with large fruit, thick rind and pink flesh. That meet these characteristics we have the following varieties:

  •  Crimson Sweet: it is the most cultivated. It has less tendency to hollow out than other varieties. The fruits are usually large (7-9 kg and oblong in shape.
  • Meridian F1:  this variety is quite productive but smaller than the previous variety.
  • Imperial F1: it  is very productive, with medium fruits and a less thick rind than the previous ones. More elongated.
  • Passion F1:  vigorous variety and medium-sized fruit.
  • Fresh water F1: less vigorous than  Pasión F1 with dark skin, medium fruit and thin rind.
  • Queen of hearts F1: it has a uniform behavior, the fruit is rounded and of medium size.

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