Citrus > Citrus General Discussion

So citrus trees are *not* generally ideally full-sun plants?

<< < (4/4)

In Florida where the sun is intense basically everything grows better with full or partial shade not just citrus. In the north the opposite is usually true you want full sun because the sun is weaker far north. My citrus and bananas did better in Ohio in the summer with longer days and weaker light compared to Florida but they took a beating in the winter even with a grow light though low humidity was a factor.

Small citrus could benefit from shade but a large one shades itself. They grow with no stress in full sun especially from seed. And a lot of seed grown ones turn into tall shade trees. The smaller size is usually from rooted cuttings or grafted on semi dwarf root stock. Most citrus will get around 20 feet. Not the tallest in the forest but up there reaching the around the top of the canopy. The smaller ones in the forest will grow tall and skinny to reach the light too.

Grapes are the same. In Europe you want full sun but in Florida they do better in partial shade.

My experience from Germany is that citrus loves light. But I observed that they use to grow in phases of wet weather, i. e. when sky is cloudy. They seem to dislike too high temperatures (around 25C/77F) and too much sun. I also saw that plants that stand in a position of only partial sun often do better than those that enjoy sun for almost the whole day. All, however, dislike shadow.
My plants are mostly grown inground in a glas house with south-east-orientation. The sun here in Germany is always significantly darker than in Italy and never stands higher than, lets say, 45 (my guess for solstice in June 21th).

You learn something new every day. Thank you for this.

From the Southeastern Citrus Expo

 "Dr. Christopher Vincent, Associate Professor Horticultural Sciences University of Florida, will share his research on the effects of water and shade on citrus health, citrus greening, and other citrus growing challenges."

He discussed shade on citrus production.  It is a complicated topic, photosynthesis comes to an intermittent stop because of moisture loss in full sun.  When stomata are open, CO2 can enter the leaf, but moisture can leave.  So stomata close to keep moisture in.  It cycles.  Spraying a light blocking film on the leaves improved growth. 

For most plants if water is limiting then some shade helps. With adequate water, full sun is not likely very limiting or not limiting al all. It does depend on the crop. Most broadleaf plants can't utilize full sunlight intensity. Whereas things like corn and sugarcane leaves can better utilize full sun.

In a greenhouse it's recommended that the covering be one that diffuses the light. The reason is that diffused light, because it comes from all directions, penetrates deeper into the canopy of leaves. Thus more leaves are illuminated at a lower more efficient light level. One quarter of full sunlight intensity on 4 leaves yields more photosynthesis than full sun on one leaf.

In corn leaf angle can affect total canopy photosynthesis. Upright leaves can allow deeper light penetration into the canopy. Again lower light on more leaf area is a plus.


[0] Message Index

[*] Previous page

Go to full version