What is FULL SUN anyway?

[DoomsDave]

Class:

During one of the other topics (B. hapala) Len (LJG) mentioned what he considered to be his definition of full sun, which is full, unimpeded sun all day long, without a break. (Len, advise if I got it wrong . . . )

Back in ancient times when I managed the garden shops, people were always wondering about, and confused by, the definition of full sun.

Many many of the best garden plants want full sun: many palms, roses (say what you will . . . ), leptospermum, philodendron, the list is long.

I'd always tell people that "full sun" meant at least half a day's sun, morning till noon, or noon till evening, or more. That noon component is critical because that's when the sun is hottest, and brightest. The overwhelming majority of "full sun" garden plants have to have at least that half-day to get by on to do their best. This is particularly important where you're in an urban area with buildings all around, or even in one of those suburban hoods with houses clustered together (for safety from the barbarians?).

But, thinking about it, half a day isn't really the same at all, especially along the coast of So-Cal. There, you might well get clouds till noon.

So, class, discuss what "full sun" means to you, in the world of palming. (extra credit for specific examples in different places) Perhaps, we can reach a definition.

[John Case]

for me, in the heat of the summer, anything over 3 hours after mid-day is full sun,....and then some...

[richnorm]

full sun = maximum sun available. Then there's morning sun, part sun, light/dappled shade and deep shade.

[DoomsDave]

Well, still different in San Bernardino than from La Habra.

[paulgila]

dave,noon is not when the sun is hottest,its between 3 & 6pm.

http://www.wisegeek.org/what-is-the-warmest-time-of-the-day.htm

[DoomsDave]

dave,noon is not when the sun is hottest,its between 3 & 6pm.

http://www.wisegeek....-of-the-day.htm

Well, fullest sun could be very different than the hottest time of the day. I agree with WG, but noon is still the most intense sun -- providing it actually hits you. Or, maybe 1 p.m., more or less . . .

[paulgila]

oh,now you mean the time of most "intense" sunshine? thats between 10 am & 4 pm.

[bgl]

Dave,

I am guessing this is one issue where there may be somewhat different definitions. The way I see it "full sun" implies a location in the garden where the plant has the POTENTIAL of being in the sun for the better part of the day. Not all days are sunny. And the fact that sun exposure has different effects in different locations (La Habra, San Bernardino, the Big Island, Thailand etc...) is an entirely different issue.

Bo-Göran

[DoomsDave]

AH, good, teasing out the subtleties a bit . . .

[Jastin]

The hottest time of day for me in the summer is 3:15. That's when my temp gauge always records the high for the day.

Full sun to me is all day. My house and front yard sits south facing, but only half of it is full sun due to a large tree.

I believe full sun is also unprotected.

Full sun after 12 is afternoon sun...because... It's the afternoon!

Morning sun is...you guessed it, before 12.

[Walter John]

Full Sun for palm growing = where the planting placement of a palm allows the plant to receive unimpeded sunshine, no shade whatsoever, for a good percentage of any given day. It doesn't mean the hottest time of the day, it doesn't mean from sun up to sun down unimpeded, it means the palm can TAKE open sun for a period of the day.

The End.

[Caryota_gigas]

Full Sun for palm growing = where the planting placement of a palm allows the plant to receive unimpeded sunshine, no shade whatsoever, for a good percentage of any given day. It doesn't mean the hottest time of the day, it doesn't mean from sun up to sun down unimpeded, it means the palm can TAKE open sun for a period of the day.

The End.

Agreed.

[Kim]

"Full sun" for gardeners is often defined in garden books as six hours of full exposure per day, with no restrictions on time of day.

[LJG]

Now you can see why it is important to ask someone what their definition of full sun really is as there are a few different definitions going around.

[Walter John]

"Full sun" for gardeners is often defined in garden books as six hours of full exposure per day, with no restrictions on time of day.

Correct Kim, for general gardeners there's that rule of thumb, but in this case we are talking palm growers.

[LJG]

"Full sun" for gardeners is often defined in garden books as six hours of full exposure per day, with no restrictions on time of day.

I might be reading it wrong, but this is not full sun to me as a palm person. By this definition I could have 3 hours full sun in early morning and 3 in late afternoon to get my six. Wal's definition would be closest to mine.

[Palmlover]

Full sun in Huntington Beach may be equal to 30% shade tent in the Inland Empire.

[Dypsisdean]

For me the term "full sun" is useless without other qualifiers. The basic definition of full sun for me has meant "open sky," or "not shaded" by something other than clouds. But there are many "full sun" scenarios that are completely different. Some that I am familiar with:

Full SoCal Sun - that can be broken down to Full Coastal Sun and Full Inland Sun

Full So. Florida Sun

Full Hawaiian Sun - broken down to Full Kona Mauka Sun and Full Kona Coastal Sun - or Full Hilo Sun (in between the other two)

All of these "Full Sun" scenarios are radically different, and what can survive in one, does not apply to any of the others. So when I use the term it is usually accompanied by something like "full morning half day SoCal coastal sun." Or "full mid-day SoCal inland sun." Or "full afternoon half day Kona mauka sun." All three scenarios are close to 6 hours of "open sky full sun" but very different situations.

Many palms that would thrive in my Kona mauka "all day full sun" wouldn't have a prayer in even "half day afternoon full SoCal inland sun."

[Jeff Searle]

Full sun? IMO, this is just that, full sun, basically no continuious cloud cover, or a good part of the day. Not a half a day, not for 5-6 hours,etc. FULL SUN...full, baking, hot sun.

[Dypsisdean]

Full sun? IMO, this is just that, full sun, basically no continuious cloud cover, or a good part of the day. Not a half a day, not for 5-6 hours,etc. FULL SUN...full, baking, hot sun.

If thats the case, I've never lived in any place my entire life that had "full sun."

[Rafael]

Interesting thread. I have always thought about what full sun is and my unsure thought is now correctly told by Wal.

Thanks Dave.

[rprimbs]

On a north facing slope -- like mine? On a south facing slope? On a west facing slope? On an east facing slope? Not on a slope but on level ground?

Does "shade" mean directly under a tree? Or morning sun, evening shade? Morning shade, evening sun? sun at noon?

[Rafael]

And by the way, what should we call partial shade? Or partial sun?

[bgl]

This is getting more and more interesting - and not necessarily in a good way! The expression "full sun" refers to the LOCATION in the garden. It has nothing to do with the weather, which tends to change! If a plant is in a "full sun" location when it's sunny, it's still in that same spot if it happens to rain one day...

[Kim]

"Full sun" for gardeners is often defined in garden books as six hours of full exposure per day, with no restrictions on time of day.

Correct Kim, for general gardeners there's that rule of thumb, but in this case we are talking palm growers.

Right Wal. Palm growers will argue about it from sunup to sundown.

[Hammer]

"Full sun" for gardeners is often defined in garden books as six hours of full exposure per day, with no restrictions on time of day.

Correct Kim, for general gardeners there's that rule of thumb, but in this case we are talking palm growers.

Right Wal. Palm growers will argue about it from sunup to sundown.

Is that arguement occurring in full sun or partial sun?!

[Hammer]

For me, the real key isn't how long it is unshaded and fully exposed...but can a plant/palm survive during a period in the day that has a combination of unobstructed sun and the most intense heat. In my garden, it is all relative.

I have noticed a huge difference even in moving just a mile this summer. Many plants (palms too) that had done ok with limited full sun (morning up till about 2pm) at this new place have been burnt up in much less sun.

[Alicehunter2000]

Full sun? IMO, this is just that, full sun, basically no continuious cloud cover, or a good part of the day. Not a half a day, not for 5-6 hours,etc. FULL SUN...full, baking, hot sun.

I agree, this may be a Florida thing.....full sun means all day unobstructed sun. This argument may be the reason that alot of plants that people say should be in full sun, don't really do that well for me. I have ofton found that even though the tag or advice says full sun.....what the plant really needs is dappled shade or morning sun (i.e full sun before 12pm). Most things just don't do well in full Florida sun....even in North Florida.

[LJG]

I have found that someone's definition of full sun is also related to what they have to work with. Dean is a classic example. Like he said, according to Jeff or Wal's definition, Dean never lived in a place with "full sun". At one of the last palm tours with the PSSC I heard the home owner state a palm he was talking about was doing great in "full sun" at his place. His place was covered in plant material and I would bet his full sun was really 3 hours of sun. But to him, a somewhat open, sunny space is full sun in his garden.

[kahili]

This isn't that complicated...think of the day comprising morning sun,usually from when the sun starts to hit the area anywhere from 8-9 am to between 12-1 in the afternoon, and afternoon sun which would be between 12 and 1 pm to around 6 or so. Full sun would be the morning and afternoon exposures combined. Obviously full sun is anywhere where there are no trees or buildings to shade the area. Of course there can be some variations as to when the sun hits the area and when it stops hitting the area (such as 10 am to 5-6 pm) but full sun has to include the majority of the afternoon sun (at least to 4-5pm) . Afternoon sun is way stronger than am sun. If I needed full sun for a plant to do well, and had to choose between am and afternoon sun, I would always choose afternoon sun.

Where you are is irrelevant to this discussion, because the above definitions always apply. Afternoon sun is always stronger no matter where you are, and the hottest part of the day is between 2-4 pm.

[John Case]

This isn't that complicated...think of the day comprising morning sun,usually from when the sun starts to hit the area anywhere from 8-9 am to between 12-1 in the afternoon, and afternoon sun which would be between 12 and 1 pm to around 6 or so. Full sun would be the morning and afternoon exposures combined. Obviously full sun is anywhere where there are no trees or buildings to shade the area. Of course there can be some variations as to when the sun hits the area and when it stops hitting the area (such as 10 am to 5-6 pm) but full sun has to include the majority of the afternoon sun (at least to 4-5pm) . Afternoon sun is way stronger than am sun. If I needed full sun for a plant to do well, and had to choose between am and afternoon sun, I would always choose afternoon sun.

Where you are is irrelevant to this discussion, because the above definitions always apply. Afternoon sun is always stronger no matter where you are, and the hottest part of the day is between 2-4 pm.

Actually, where you are does make a difference for full sun. Many plants take full sun in nature, but when brought to peoples gardens, they may not make it. For example, in my area, full sun plants are often cautioned, 'protect from afternoon sun'. This applies in my area because of extremely high temps in the summer (over 105) coupled with extremely low humidity (under 10%). Once summer passes then full sun warnings are ignored.

It does makes a difference; based on location, season, and 'nativeness' of the plant.

[Jimhardy]

9-3pm(at least 3pm)in summer.

10-2pm(at least) in winter

[kahili]

John-as far as I can tell reading the original post-we are only talking about what constitutes "full sun". Not what the requirements are for various plants-whether they are in your yard, my yard or in their native habitat. If I am correct in reading the first post-then its not complicated. Each person has to fully evaluate what full sun will do to whatever plant they are planting in their yard-but the definition remains the same

To have a discussion of the magnitude that you are referring to would almost be pointless..way too many variables (plants and locations) to make it a meaningful discussion, imo. Except, I guess if one person gets a certain plant and wants to know how much sun/shade it would take-but even then, the only really relevant answers would be from people in his area. But full sun would still be full sun.

[Kim]

This isn't that complicated...think of the day comprising morning sun,usually from when the sun starts to hit the area anywhere from 8-9 am to between 12-1 in the afternoon, and afternoon sun which would be between 12 and 1 pm to around 6 or so. Full sun would be the morning and afternoon exposures combined. Obviously full sun is anywhere where there are no trees or buildings to shade the area. Of course there can be some variations as to when the sun hits the area and when it stops hitting the area (such as 10 am to 5-6 pm) but full sun has to include the majority of the afternoon sun (at least to 4-5pm) . Afternoon sun is way stronger than am sun. If I needed full sun for a plant to do well, and had to choose between am and afternoon sun, I would always choose afternoon sun.

Where you are is irrelevant to this discussion, because the above definitions always apply. Afternoon sun is always stronger no matter where you are, and the hottest part of the day is between 2-4 pm.

The distinction you are making about morning sun vs. afternoon sun is a question of heat, not sun exposure. Plants that need full sun can get it from 7 am to 1 pm. If a plant requires heat, then of course the gardener will look for the warmest location, with hot afternoon sun. But 6 hours of sun, whether morning, afternoon, or a bit of each, constitutes "full sun". This is an accepted measure in the nursery trade, and is based on plants' requirements to flower, whether palms or petunias. By practical necessity, it is a generalization used for labeling plants to be sold to the general public.

When we discuss sun/shade requirements on an international palm-specific forum, the generalization is inadequate, and the specialists share their own refined and more specific terms, but that does not change the basic definition of "full sun".

[kahili]

Kim, I would disagree, and I am in the nursery industry. We would not refer to 7am to 1pm as full sun. That would be morning sun,and at 7am-barely that. The sun is just not bright enough to qualify at that time of morning! And there is a huge difference in light intensity (not heat) between am sun and afternoon sun-of which you have to have some of to have it be full sun. Its all about the amt of light intensity and how much of it a plant gets/needs. I would also say that full sun is more like 8 hrs a day-not 6 hrs

Here is something that I just copied-

Figure 2. Light intensity for indoor and outdoor situations.

Landscape plants vary in their adaptation to light intensity. Many gardening texts divide plants into sun, partial sun and shade. However the experienced gardener understands the differences between these seven degrees of sun/shade:

• Full sun – Direct sun for at least 8 hours a day, including from 9 a.m. to 4 p.m.
  
• Full sun with reflected heat – Where plants receive reflected heat from a building or other structure, temperatures can be extremely hot. This situation significantly limits the choice of plants for the site.
  
• Morning shade with afternoon sun – This southwest and west reflected heat can be extremely hot and limiting to plant growth.
  
• Morning sun with afternoon shade – This is an ideal site for many plants. The afternoon shade protects plants from extreme heat.
  
• Filtered shade – Dappled shade filtered through trees can be bright shade to dark shade depending on the tree’s canopy. The constantly moving shade pattern protects under-story plants from heat. In darker dappled shade, only the more shade-Tolerant plants will thrive.
  
• Open shade – Plants may be in the situation where they have open sky above, but direct sunlight is blocked during the day by buildings, fences and other structures. Only more shade-tolerant plants will thrive here.
  
• Closed shade – The situation where plants are under a canopy blocking sunlight is most limiting. Only the most shade-tolerant plants will survive this situation, like under a deck or covered patio.
  

Here is the link to the article http://www.cmg.colostate.edu/gardennotes/142.html#quality

Hope this helps!

[Dypsisdean]

Why are we asking for the definition of "full sun?" Is it purely for definitive purposes, or is it to help determine the best place to plant a palm?

If it is the latter, then simply hearing that "palm x" grows best in full sun (direct sun for at least 8 hours a day), means very little. And planting "palm x" in those conditions could easily kill it in many locations.

It's a little like asking "What is hot?"

[Kim]

Thanks for the information, Kahili. I can find a dozen other university sources that say "6 hours", "minimum 6 hours", or "at least 6 to 8 hours" equals full sun. Let's not google each other to death over this.

The article you cited seems to contradict your own statement that morning sun "is not bright enough to qualify". Morning sun in the fine summer weather we had in California recently was brilliantly hot very early. Light intesity may be greater at certain times, but plants do grow and photosynthesize in morning sun. No matter how anyone measures it, morning sun will not qualify as shade.

[BS Man about Palms]

Very interesting coming into this thread at this point. In simple terms, relatively speaking, we are ALL the same distance from the sun. So, its a factor of "other things" that affect how our palms (or other plants) will react to the "other things".

To me, chief among them is humidity. For if you managed an all day sun at the beach and one at the Sahara desert, the reaction of the plant would be very different, assuming the same temps.

The "other things", can be angle, actual temp, humidity, cloud cover, and even to a point the "location exposure" for lack of a better description. For if you had a mini courtyard roughly 8foot/3 meters square with walls on all sides, I can GUARANTEE you the temp will be hotter there due to the reflected and radiant heat than out in the center of your open yard of your same property.

So, to me the "other things" at a site would/will affect my definition of what is "full sun" in any given place.

If I read correctly, many of us are more or less agreeing and there are several salient points amongst these posts.

[kahili]

Dean-I think its more to define how many hours a day a plant needs for full sun-not how well a plant will do in a certain location with x amt of hours of sun. I think that when Len gave an example of being in a yard where the owner said that the plant was in "full sun" and it only got a few hours of sun, that that person probably did not have an understanding of what full sun meant. It might help to understand when a plant that needs full sun and is not getting it,and is not doing well that the reason may be that its not getting enough sun, because its not getting "full sun". I can see where this discussion could help with gardening in general.

Kim, I certainly don't mean to "google" you to death! As a commercial plant grower for over 20 years-I don't need to google what full sun means. Any nursery person will tell you that they live and die by the amt of sun that their plants get. Its something that we think about all the time, mostly every day. It just threw me when you said that full sun could be from 7am -1pm-hence the chart -which I do think contains some interesting info for anyone reading this. Any commercial grower would never accept 7am -1 pm as full sun. The amt of foot candles available at 7 am is mostly insignificant when growing plants that do require full sun. Thats why the chart started full sun at 9am. It also does not negate what I said in my previous post. What I said is that full sun was a combination of morning sun and afternoon sun-which is what you need for at least 8 hrs of good growing sunlight. I guess that I don't really qualify 7am as morning sun though. I said 10 am. the chart says 9 am-either is fine as a starting point for a full sun exposure.

Bill, while I agree with you that there are many other factors in how a plant grows where-I am simply addressing what the title of this post is-"What is full sun?" Its the same everywhere. It may be that some plants cannot handle full sun in one place on earth-but can somewhere else. I am sure thats the case-but thats not what I am addressing-just to clarify!

[Walter John]

So, class, discuss what "full sun" means to you, in the world of palming.