More sunlight on plants



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Content: The more sunlight that plants get, the better they will grow. There are some ways to be sure that crops get the most possible sunlight. Stake vine crops correctly. Prune and train fruit trees so that maximum sun reaches the leaves. Pay attention to the alignment of rows of plants relative to the sun.

All green plants need sunlight. It is especially important that the sun shines on the plant’s green leaves. When sunlight shines on the green leaves, a substance* in the green leaves uses the sunlight’s energy to convert air (CO2), water, and soil nutrients into food the plants can use to grow. So plants need lots of sunlight in order to produce the most possible food for us. Let’s think today about some good methods that you can use to make sure that your crops get the most possible sunlight.

Vine crops in rows

Do you plant vine crops in rows, or a crop like tomatoes that can be tied onto stakes? If you do, you may be interested to know that farmers in China have a way of getting plenty of sunlight on their plants. They set tall bamboo stakes in rows 60 centimetres (2 feet) apart. These stakes are 2 to 2.5 metres (6 1/2 to 8 feet) tall. In each pair of rows, the stakes are slanted together so that they cross each other halfway up. To make the stakes steady, long, thin, horizontal bamboos are tied from one crossed pair to another at the place where the stakes cross each other. The climbing vines are then planted at the base of each stake. When they grow on these crossed stakes, their leaves will get the most possible sunlight falling on them. This will result in a high yield from this crop.

If you plan to grow an additional low-growing crop on the ground, vertical poles for your climbing vines will allow more sunlight to reach the leaves of the crop at the ground level.

Prune and train fruit trees

If you have fruit trees on your farm, you will want to make sure that the leaves of your fruit trees get the most possible sunlight so that they produce lots of fruit. There are different ways of doing this which really depend on the kind of fruit trees you have. Here are some examples of how farmers train their fruit trees to get the most possible sunlight shining on their crops.

This is a method taught to Chinese farmers at the Renshou Branch of the Central Agricultural Broadcasting School for citrus trees. When your citrus tree is young, carefully wedge a stick with notched or forked ends between the young branches to make them grow farther apart. Leave it there until the branches grow into that position. This will help to open up the tree to get more sunlight into the middle of the tree. Doing this will also make the branches and the crotch of the tree stronger.

Namu Lataw is a hilltribe farmer near Chiang Mai in Thailand. She has a way of training the branches of her pear trees so that the leaves will get the most possible sunlight. She builds a simple frame or fence around her trees. This fence is simply four posts with a single lightweight pole attached to the posts 1 – 1.5 metres (3 – 5 feet) above the ground. This fence is put close enough to the trees so that the branches can be tied down to it. This keeps the branches from growing upright as they naturally want to grow. It also prevents them from breaking because they are held up by the fence. It is a good idea to occasionally prune the new growth that appears in the centre of the crown. The leaves on Namu’s pear trees get plenty of sunlight, and that’s one reason why she gets plenty of good fruit from her trees.

Here is one more suggestion for farmers who grow coconuts. In southern India near Madras, farmers have a method to get higher yields from their coconut trees. As you know, the newer, upper leaves of coconut trees tend to grow straight up from the tree. The sun does not shine down directly on the leaves. A person climbs up to the top of each tree and actually presses down those top leaves so they become parallel to the ground, at right angles to the tree. This way the leaves get the most possible sunlight on them and the farmers get much higher production and more coconuts to sell in the market.

Row crops

There are also ways of making sure that each plant in a row of crops gets the most possible sunlight. Let’s think about two different ways to plant row crops—first planting in rows in a south-north direction and then in an east-west direction.

As you know, of course, the sun rises in the east and sets late in the day in the west. If the rows are planted in a south-north direction, then most of each morning, the sun shines only on the east side of all of those rows. It does not shine on the west side in the morning. Also, at least in the earlier morning hours, leaves on the lower part of the east side of every row are shaded by plants in the row next to it. Then, during most of the afternoon, the sun shines only on the west side of the rows. Again, lower leaves of the plants, this time on the west side, are shaded.

Now let’s think about another way of planting those crop rows. Is it better to plant these row crops in rows that run east and west? If rows are set out this way, does the sun shine differently on the plants? Yes, it does. It shines down between the rows all day long. It shines down on both sides of each row, even on the leaves near the bottom of the plants. That’s because the plants in one row do not shade the plants in the next. Each plant in the rows gets the most possible sunlight. That’s important to think about when you’re planting your crops in a level field or garden.

* this substance is called chlorophyll; it is the pigment which gives leaves their green colour

Information sources

  1. Professor Cheng Yichun and Professor Zhang Guan Lun, Department of Horticulture, Sichuan Agricultural University, Ya An, People’s Republic of China.
  2. Huang Yu-Shu, Director, Su She Fu, Vice Director, and Yang Wei Xun, Senior Agronomist, First Chengdu Institute of Agricultural Science, Sichuan Province, People’s Republic of China.
  3. Miss Zhoc, Farmer and Student, Renshou Agricultural Broadcasting and Television School, Sichuan Province, People’s Republic of China.
  4. Madam Vijaylakshri Natesan, Farm Manager, Tamil Nagar, Madras, India.