How much sun do pines really need?

[Brian Van Fleet]

Full sun to me means unprotected exposure during at least 4 hours of either first light or end of day light. In our area, full sun during the middle of the day can be brutal and may keep some plants (like hornbeam) from thriving, or actually kill them. I think that is probably the heat during the middle of the day and angle of the sun in our area (8a), more than the actual sun. IMO, if you can get 4 hours of direct sun, that will be sufficient for the plant to thrive if it is a full sun plant. In 8a, junipers seem to be able to take the most direct, hottest exposure we have, and are planted beside the city streets in parking lot beds and in roadway median flower beds. Any plant that survives planting in the strip separating automobile traffic likely loves the direct sun. Not your question, but there are excellent bonsai in many roadway, and parking lot beds in my area. Cars and sun exposure seem to accomplish a lot of the same rugged looks that growing on the diff side of a mountain accomplishes. There is only the problems you will encounter when the police discover you in the middle of the road with a shovel harvesting a nice juniper for your collection.

Full sun is full sun. Horticulturally it’s defined 6-8 hours of direct light. Hornbeams are not full-sun plants in our climate. Pines & junipers are.
In other words…

 

[WNC Bonsai]

You also need to consider the intensity of sunlight. Therefore 6-8 hours at the equator is different than it would be in Michigan or Wisconsin, etc. Peter Warren discussed this in one of his YouTube videos and pointed out that in England the solar intensity is inadequate to reliably produce two growth spurts for JBP in one season. He said that on a really, really good summer with little cloud cover it might happen but otherwise don’t count on it. Here in NC we get much higer solar intensity so I do fine with only 6 hours.

 

[Mike Corazzi]

She Who Must Be Obeyed

A hard pruning might correct that a bit.

 

[Leo in N E Illinois]

I only know growing in my 600 ft above sea level climate. Most pines need full sun as Brian van Fleet defines it, 6 to 8 hours of direct sun, and bright shade for the rest of the "day". However some pines like Pinus banksiana need sunrise to sunset unobstructed full sun, or they will "fail to thrive". Some pines clearly need more sun than others. The eastern white pine does quite well in 50% shade, though it grows loose and open, even more so than normal making it even less acceptable for bonsai than it already it. Pines like Pinus sylvestris really do best with about 8 hours or more of unobstructed sun during the summer.

So in general consider most pines to be full sun, even more sun than roses or tomatoes, updating my old reference. You might get by with a little less but then grow tends to be loose and lanky.

 

[Paradox]

Since this thread has been bumped for further discussion and since I am the OP of the thread.

6+ years later I have learned that my yard has spots that get enough sun for pines based on the fact that Ive been able to keep several species alive for 10+ years. I have done "sun studies" of my back yard at different times in the season (May vs July/August" to gauge how sun exposure might change over the season. This involved drawing a diagram of my yard with the bench locations labeled and checking once an hour as the day progressed and recording whether the benches were in shade or sun. We also relentlessly cut any branches from my neighbor's trees that extend over our fence (perfectly legal to do as long as the branches are encroaching on our property and we offer to give the wood cut back to the neighbror).

As for some of the discussion. I am at elevation 39, basically sea level and I do keep 3 species of high elevation pines (Scots, mugo, JWP).
During the height of the summer, the bench area where I keep my pines gets sun from early morning to mid afternoon. So far they seem to do fine.

 

[roberthu]

I hope more people chime in and share how many hours of direct sunlight their trees get. It will be interesting.

 

[chicago1980]

Full sun
sun rise to sun set
East to west
South facing
3000 miles north of equator
595 ft above sea level
General score low to moderate on uv index

 

[cmeg1]

18 hours

 

[cmeg1]

Mine are a lower intensity,of course.Outdoors they grow in much better ways that are nearly impossible indoors…….like proper candle extension only happens when these are put in natural sunlight.It just does not occur in my grow tents.They just set a terminal bud eventually and get fatter and bushier.When a terminal bud does erupt it is rather short.No 2 footer candles in a grow tent.

 

[penumbra]

She Who Must Be Obeyed

I have one of those. I think they are everywhere.

 

[penumbra]

Mine are a lower intensity,of course.Outdoors they grow in much better ways that are nearly impossible indoors…….like proper candle extension only happens when these are put in natural sunlight.It just does not occur in my grow tents.They just set a terminal bud eventually and get fatter and bushier.When a terminal bud does erupt it is rather short.No 2 footer candles in a grow tent.

That is an awesome set up my friend. Your grow tent is pretty low isn't it? Or is that an illusion? I would love to have the space to set up a couple more grow tents but I would want lower ones than the one I have which is 60 inches.

 

[cmeg1]

That is an awesome set up my friend. Your grow tent is pretty low isn't it? Or is that an illusion? I would love to have the space to set up a couple more grow tents but I would want lower ones than the one I have which is 60 inches.

These are next to 60” perhaps…….more lights need hogher tents if you want to conserve co2.
There will be higher temps and your exhaust will turn on too much.
Probably 2.5’ above the lights.
I have 3 tents……3x3—-2x3———18x3

I need a window vented floor ac running and also a seperate demunidifier running all year.
I prefer to vent quality dry and cool air into the tents as this saves co2 BIGTIME!!!
It vents in usually when humidity maxes at 60-65%.

 

[penumbra]

These are next to 60” perhaps…….more lights need hogher tents if you want to conserve co2.
There will be higher temps and your exhaust will turn on too much.
Probably 2.5’ above the lights.
I have 3 tents……3x3—-2x3———18x3

I need a window vented floor ac running and also a seperate demunidifier running all year.
I prefer to vent quality dry and cool air into the tents as this saves co2 BIGTIME!!!
It vents in usually when humidity maxes at 60-65%.

This is quite a passion for you.
I will wait for your book.

 

[cmeg1]

This is quite a passion for you.

It is I prefer part-time jobs in the evening and gig work in the morning so I have time in the morning to just live with Bonsai!!!!!

 

[Leo in N E Illinois]

@Zerobear - I wrote a message, re-read your message, realized I had no clue what the hell I was taking about, and so I deleted my message. Sorry, if you read the message and are spinning up a response, "sorry about that"

I gotta lay off the Nyquil when typing on BNut. I'm seeing things this morning.

 

[MaciekA]

Mine are a lower intensity,of course.Outdoors they grow in much better ways that are nearly impossible indoors…….like proper candle extension only happens when these are put in natural sunlight.It just does not occur in my grow tents.They just set a terminal bud eventually and get fatter and bushier.When a terminal bud does erupt it is rather short.No 2 footer candles in a grow tent.

Hey Curtis, granted we're in a pine thread but I believe you use similar lm301h based lights as I do and I'm curious: Have you tried juniper under these lights and found any similar parallels to your pine findings? Specifically the "interesting/strong growth, but also weird and missing some features only found outdoors" part.

Also with the pines, have you A/B'd high CO2 vs low CO2 to see if that's a confounding factor in "proper candle extension"?

BTW, the seedlings you sent me are doing great! Just grafted a wart bark JWP onto one of them last weekend.

Cheers

 

[Frozentreehugger]

For me sun is a struggle . Live zone 4 old town . Large lot but old tall ceiling 2 story house on southeast corner is worst culprit . There are other things in the way like big old trees . Slat best central back yard gets 6 hours . My max sun spot gets crowded . Just restarting bonsai but grew . Mainly Scits and Nigra before . Plus low southern sun in spring . Best is hot mid summer . Larger problem for me . Is short growing season . Still slight snow outside today . Traditional plant garden time is mid May . When I see you guys post about the growth you get in one season . I LMAO . I have a small area top Center of my roof of house . That is flat and can access thru a trap door . Full sun all day breeezy 35 feet in the air . Going to try that this year . Should be fun hauling water good exercise . the crazy things we do . For success Wait we are painstakingly growing tree in pots that need daily care . When we an just plant them in the ground . And walk away done but then there would be no reason to talk here . And the neighborhood. Already thinks I’m nuts . After all who waters plants in the rain . Hey come look at the crazy .

 

[Frozentreehugger]

For me sun is a struggle . Live zone 4 old town . Large lot but old tall ceiling 2 story house on southeast corner is worst culprit . There are other things in the way like big old trees . Slat best central back yard gets 6 hours . My max sun spot gets crowded . Just restarting bonsai but grew . Mainly Scits and Nigra before . Plus low southern sun in spring . Best is hot mid summer . Larger problem for me . Is short growing season . Still slight snow outside today . Traditional plant garden time is mid May . When I see you guys post about the growth you get in one season . I LMAO . I have a small area top Center of my roof of house . That is flat and can access thru a trap door . Full sun all day breeezy 35 feet in the air . Going to try that this year . Should be fun hauling water good exercise . the crazy things we do . For success Wait we are painstakingly growing tree in pots that need daily care . When we an just plant them in the ground . And walk away done but then there would be no reason to talk here . And the neighborhood. Already thinks I’m nuts . After all who waters plants in the rain . Hey come look at the crazy .