I'm not an expert, but misting during the the day in full sun probably isn't a good idea, as the water may end up "burning" the leaves. Those little droplets of water catch the sun and act as magnifying lenses and will burn the leaves. When the sun goes down and the trees are no longer in direct sunlight, I think misting would be fine.

I mist mine, but on occasion use a solution of fish emulsion (5-1-1) to feed the foliage. They seem to love it. On other occasions, I just set the hose to "mist" and soak them all over after a particularly hot day. You can almost hear them sigh. lol. So far, I've not noticed any damage from doing so.

Water droplets on foliage really don't act like a magnifying glass. The droplets would have to be much further away from the leaf (not sitting on it) for that to happen. For example, what would happen if you placed a large droplet of water on the back of your hand and sat out in the direct sunlight? Nothing.

However, an occasional misting won't do much good, I don't think.

If the ambient air temperature is around 90, then I'll bet that the cement driveway is hotter than blazes! It is reflecting heat AND sunlight all day long, then continuing to give off heat even after the sun goes down. It just seems to me like this is a very stressful location. ;-(

I would think if you put a droplet of water on your hand and held it out in the intense sunlight for a while...you would...DUH....get sunburn.

Foliage is no different. I stand by what I said. It's a no-no to do with herbs, as it will burn the plants in the intense sunlight (I've seen it happen often enough to know what I'm talking about), and I can't see where citrus leaves would be any different.

So let's just agree to disagree and not go the "know-it-all" route.

Sooner or later I'm gonna get the message and stop posting on the GW and stick to the other citrus forum where grown-ups talk to each other. People here bicker and contradict each other too much. Geez.

I thought I remembered reading about a study done at UC Davis several years ago that indicated that water droplets on foliage does not cause sun burn, but I haven't been able to find it again and may be mistaken.

I'm sure you are right about the stressful location, Rhizo. If I move them off of the cement then they are in the shade, but I guess when it is this hot shade would better. I'll give it a try. My 6 year old Meyer seems to take it in stride, so maybe my other two will adapt.

Thank you both for your input. Wobur

You're welcome, a good luck!

Me thinks that YOU are the only one bickering, herbolic! Chill out! We're talking water droplets here, for cryin' out loud. ;-) Please don't mistake someone offering differing information for bickering. These forums are terrific learning experiences for all of us.

However, the 'magnifying lens' thing is one of those old myths that continue to surface. WeÂre mistaken in thinking that water droplets act like little magnifying glasses for several reasons. First and foremost is that the water droplet SCATTERS light rather than concentrating it. The droplet is flat side down, after all.

Secondly, the water droplet is constantly evaporating and continuously changing shape until it completely evaporates. Even if it were the right shape and the right distance away, it wouldn't stay static long enough to burn anything. And if you want more pragmatic proof, think about the last time a cloudburst occurred that was followed by bright sunny weather. If the magnification principle were true, every plant in the neighborhood would be covered in spots. Some myths die hard.

It's time to let that one go.

Anyhow, Wobur...I've been thinking about your situation and just can't brainstorm a good solution. I'm pretty sure that if I were in your position, I'd move them to a different location for the time being. I hope they perk up.

I let it go. YOU seem to be going on and on about it.

I agree with Dorie. The only way water will "burn" foliage is if you're irrigating from a whistling tea kettle (but then, isn't that technically blanching?) ;o). While it's possible for localized necrosis to occur as a result of fungal infection exacerbated by wet foliage, or for some osmotic migration of water from plant tissues due to carbonate precipitants from irrigation water remaining on foliage after evaporation and "pulling" water from plant cells, there is no "burning" of plant tissues due to refractory focusing of light rays through water droplets. It's a physical impossibility - as noted above.

I'm not sure about the rest of the forum, but I don't think it bickering when someone tries to belay a myth perpetuated by anecdote.

Al

To add a little more information, the water droplet would be considered a plano-convex lens and would converge light coming into it. The reason the leaf does not burn is that the shape/distance relationship is wrong. That is, the surface of the leaf is not at the focal point of the sunlight going through the droplet.

PaLEEZE, you two. Stop that bickering. ;-) (just kidding)

Does anyone have a smart solution for wobur's plight, other than relocating the plants from the driveway?

Wober, I mist religiously..Since I've been growing plants, I've misted and hosed all types,(except fuzzy leaves) during strong, afternoon sun, but I don't recommend it..I do not want someone trying it and burning foliage..lol
It's best to mist/hose in early morning or late afternoon, and anytime on cloudy days.
Wober, since you have the hose handy, why not just use that to spray foliage? Toni

I water twice every day, morning and night. My ponderosa sits on concrete patio stones which get very hot. As long as I water 2 times per day the leaves do fine and the fruit is growing every day. It was around 98 degrees today and at 10:30 p.m. is is still in the mid-80s. It is supposed to coll-off Sunday, down to 95*.

Good discussion everyone! Thanks! I moved my trees to a part of the driveway where they get partial shade later in the day and at least I feel better. If I actually moved them off of the driveway they would get shade all day and they are too heavy to move back on. I have been misting them some but not sure it is helping. I have ordered cooler weather for next week! ;-) Wobur

I realize this is a very old post, but to provide an update, I noticed that my citrus trees in shade appeared to be much healthier than those in full sun; especially when the 90-110 deg F weather started here in Houston in June/July. As an experiment, I briefly watered some with the hose twice a day (12:00 PM and 6:00 PM) during the "heat of the day". The citrus trees that received this brief (15 second) watering of the leaves (I did not try to drench the soil) did MUCH BETTER than the control group (that did not receive the brief watering of the leaves twice a day).

Best of luck to all.

Same as humans running through the hose.

I want to go back and rehash the magnifying glass concept....it's been 13 years since we argued over that :>)

The citrus trees in California seem to do better in full sun than the South Texas coast. If I had to guess, and it's only a guess, the difference in humidity (Houston humidity stays around 80%), and nighttime temperature (Houston nighttime temperatures rarely drop below 80 deg F at night when the daytime temps are above 100 deg F). The elevation is about the same, so I don't think that has anything to do with it.

that I have no knowledge of

The other glaring difference between agricultural areas of California (such as Modesto) and my location in South Texas is the daily average temperature curve. I think this might be the most telling variable. Today where I live in South Texas (Fulshear, Texas to be exact), the average daily temp will be 86. In Modesto, CA, the average daily temp will be 79. This is despite the fact that the high temperature in Modesto will be 100, versus the high temperature in Fulshear will be 98. I bet this will be the case on nearly every summer day. In other words, the average daily temperature in Modesto, CA is about 10 degrees less than the average daily temperature in Fulshear, Texas. Since tomatoes seem to do best when the average temperature is about 80 degrees F, it makes sense that they do better on average in Modesto, CA versus Fulshear, TX.

just put them in a bit of shade and check for incects

The citrus trees are all planted in the ground (most for at least 2 years now). Again, the ones in the most shade are doing the best. The ones in full sun, are struggling, but a quick drench with the hose in the morning and afternoon has helped.