Soil temps

[pj_orlando_z9b]

Is there a point where high soil temps could inhibit palm growth? Most of my yard is about 80F but checking my adonidia which is surrounded by concrete, I measured 90F.  I know this is fine but got me wondering how tropicals can be impacted by high soil temps. A better way of asking is, what is a point of too much? 100+?

Edited June 1, 2019 by pj_orlando_z9b

[Silas_Sancona]

Not sure about there in Florida..  everything i was growing grew like mad through the summers there, regardless of the soil temperature.. 

That said, here in the desert, intense heat / extra dry air slows alot of things down this time of year.   Once Monsoon season starts, raising humidity, bringing rain / putting moisture into the soil, and less intense heat, that is when you'll see a pretty big burst of growth that can extend well into the fall if it stays warm and moist, like last year.  Typically moister soils will stay cooler, even here.  Suspect 85F- maybe 105F is sorta the "sweet spot" soil temp wise for optimal growth. Once you reach what i pictured below, ya pretty much fry everything, lol

The first summer i was here, this is what i recorded out in the most exposed portion of the back yard at around 4:30pm on a day when the air temp had reached 119F ( 6-3-2016 )



  Actual soil temp might be off by a few degrees, but hot enough for sure. THE reason 95% of what i have in pots is placed where they get no / filtered afternoon sun. Learned that the hard way that year..    Supposed to only reach 99-101F on Monday  this year thankfully..

Edited June 1, 2019 by Silas_Sancona
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[palmsOrl]

I have my three Cocos in black plastic pots in full all-day sun on days when the temperature is in the mid to upper-90s F.  I wouldn’t doubt that the soil temperature at times can reach at least 110F and they are looking great and growing fast.  I think palms from hot tropical climates can tolerate or even thrive with daytime soil temperatures of 100-110 F as long as they have enough soil moisture.

[AZPalms]

Yep. Exactly what Nathan said. I’ve measured soil temps in my yard like Nathan’s above here in Phoenix. With the addition of 2” of mulch, soil temps drop drastically. It’s also amazing what shade cloth can do for soil temps with mulch. With extreme heat of soil in pots here in the desert, frying the palms usually is the end result. 

Desert native palms such as Brahea and even some Phoenix like dates, don’t show growth in my yard until this time of year where warm (hot) soil and air arrive. I’d even lump Bismarkia into this group. 

[Silas_Sancona]

3 hours ago, AZPalms said:

Yep. Exactly what Nathan said. I’ve measured soil temps in my yard like Nathan’s above here in Phoenix. With the addition of 2” of mulch, soil temps drop drastically. It’s also amazing what shade cloth can do for soil temps with mulch. With extreme heat of soil in pots here in the desert, frying the palms usually is the end result. 

Desert native palms such as Brahea and even some Phoenix like dates, don’t show growth in my yard until this time of year where warm (hot) soil and air arrive. I’d even lump Bismarkia into this group. 

Mulch, even stone ( pref. lighter colored if covering a larger area ) or leaving grass,  grass / weed clippings on the soil in areas of the yard not yet developed helps keep soil temps down /moisture in the soil longer. If you're lucky enough to have established tree canopy over head, even better here. Shade cloth is a must if your yard is lacking natural canopy.  After the big difference in soil temp, how often / or not as often i have to water i noticed using this technique last year, mulched all the potted stuff with this years' dried leaf litter after raising the canopy / doing the annual pre- monsoon season trim on the Chilean mesquite out front.

Heat this time of year is intense enough that  even Citrus trees can slowly burn to death if fully exposed to our summer sun/  soil temperatures. Lost all 3 that were in the yard.   Once the trees i  planted get big enough, whomever lives here after i've left should have a much easier time gardening / adding to the landscape out back.  House will likely stay cooler as well.  One of the Mesquite i planted in 2017 is already over 10' in height / width. Won't be surprised if it adds another 4-8 +ft this summer.  I trim it up / remove any thorns that form along branches at head / eye level as it gains height. Sat in a 1 gal for 4 years as a as a spindly 3 ft twig until i planted it.

Palm-wise, i might add stuff from Cuba ( Copernicia, Cocothrinax, Pseudophoenix, maybe others from similar arid portions of the island ) and Hyphaene to the list of stuff that seems to grow a bit faster when soil temps are on the toasty side here.


 

Edited June 1, 2019 by Silas_Sancona
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[Donald Sanders]

On the flip side of this issue.        I often wonder about wet areas at the foot of the Andes where the water coming off mountains is very cold and could cool up the land.    Palms growing around and in chilly water?    Perhaps the water warms up fast once it gets to the lower altitude.    Here in Hawaii, to me, the water seems very cold coming off the mountain.

[kinzyjr]

1 hour ago, Silas_Sancona said:

Mulch, even stone ( pref. lighter colored if covering a larger area ) or leaving grass,  grass / weed clippings on the soil in areas of the yard not yet developed helps keep soil temps down /moisture in the soil longer. If you're lucky enough to have established tree canopy over head, even better here. Shade cloth is a must if your yard is lacking natural canopy.  After the big difference in soil temp, how often / or not as often i have to water i noticed using this technique last year, mulched all the potted stuff with this years' dried leaf litter after raising the canopy / doing the annual pre- monsoon season trim on the Chilean mesquite out front.

Heat this time of year is intense enough that  even Citrus trees can slowly burn to death if fully exposed to our summer sun/  soil temperatures. Lost all 3 that were in the yard.   Once the trees i  planted get big enough, whomever lives here after i've left should have a much easier time gardening / adding to the landscape out back.  House will likely stay cooler as well.  One of the Mesquite i planted in 2017 is already over 10' in height / width. Won't be surprised if it adds another 4-8 +ft this summer.  I trim it up / remove any thorns that form along branches at head / eye level as it gains height. Sat in a 1 gal for 4 years as a as a spindly 3 ft twig until i planted it.

Palm-wise, i might add stuff from Cuba ( Copernicia, Cocothrinax, Pseudophoenix, maybe others from similar arid portions of the island ) and Hyphaene to the list of stuff that seems to grow a bit faster when soil temps are on the toasty side here.

I certainly agree with canopy and mulching.  Anything that helps compress the temperature scale will make the environment more pleasant for your plants and you.  When I got here, the backyard had canopy and the front didn't.  The grass in back stays a nice deep green vs. the grass in front burning with frost and drought.  Same story with the bananas and other plants.  Mowing in the summer is a real chore when it hits the high 90s or low 100s with high humidity and the sun beating down on you in the front yard, but it is a lot more bearable in the back.  It didn't take many trips with the mower to decide on getting another live oak for the front.

With the recent heat wave, the philodendrons in direct sunlight have some scorching on the leaves.  The ones shaded by live oak most of the day are in much better shape by comparison.  You can see the comparison below:

[Silas_Sancona]

20 minutes ago, kinzyjr said:

With the recent heat wave, the philodendrons in direct sunlight have some scorching on the leaves.  The ones shaded by live oak most of the day are in much better shape by comparison.  You can see the comparison below:

Yep, Can't remember which year it was, ..2015 i think.. Remember suffering leaf burn on my Plumeria after a similar heat wave while in Bradenton. Was the only time i experienced that while there in FL. Remember seeing similar burn as the pictures you shared on some stuff that was in sun where i worked in Sarasota at the time also.. Here, that can happen almost every summer, esp. plants fully exposed to all day sun, and /or in pots... Even under 1 layer of shade cloth if it is hot enough for several days in a row... Same with anything "leafy" ..like Philodendron, Gingers, etc..  Yet, if you have good tree canopy, all those plants can look great ..esp if given regular water, at least until Monsoon season is underway.  There's a nice Riparian-themed display located at Tohono Chul Park in Tucson where the Tree canopy surrounding a stream is dense enough that is is quite a bit cooler beneath it.. Would be a great spot where one would probably be able to grow stuff like Chamadorea metallica, or ernesti augusti  if a similar environment existed in their yard..

Sounds crazy but our intense sun / high soil temps this time of year can even torch various Cacti and Agave, hence why ..if you toured some place like Desert Botanical in June, July,  and/or August, you would see shade cloth slung over numerous things in various displays there.. On top of that, watering certain stuff when air / soil temperatures are this hot can cook it just as fast as rot that can happen under cold / wet  soil / air temp conditions in winter. Outside this time of year, nearly perfect growing conditions for 99% of things..

[Steve in Florida]

Some years ago I did some testing and found out that Washingtonia filifera switches from growth mode to preservation mode, and thus grows much more slowly, once an air temperature of 117F is sustained.

[pj_orlando_z9b]

Good discussion. I figured areas of the desert likely has soil that bakes and natives are likely adapted to those high temperature fluctuations. I couldn't imagine the Middle East where that sand could hit regular 120-140 temps. 

[pj_orlando_z9b]

On 6/1/2019 at 5:26 PM, kinzyjr said:

I certainly agree with canopy and mulching.  Anything that helps compress the temperature scale will make the environment more pleasant for your plants and you.  When I got here, the backyard had canopy and the front didn't.  The grass in back stays a nice deep green vs. the grass in front burning with frost and drought.  Same story with the bananas and other plants.  Mowing in the summer is a real chore when it hits the high 90s or low 100s with high humidity and the sun beating down on you in the front yard, but it is a lot more bearable in the back.  It didn't take many trips with the mower to decide on getting another live oak for the front.

With the recent heat wave, the philodendrons in direct sunlight have some scorching on the leaves.  The ones shaded by live oak most of the day are in much better shape by comparison.  You can see the comparison below:

Interesting. Is that winter growth that wasn't adjusted to May sun?

[palmsOrl]

I have read that the sand surface in some deserts can reach 160-180F, though I doubt the full root-zone of anything but seedlings could experience anything close to that.

[kinzyjr]

2 hours ago, pj_orlando_z9b said:

Interesting. Is that winter growth that wasn't adjusted to May sun?

Some of it toward the bottom of the plant could be considered that, but the burned leaves at the top are relatively new.  Either way, the shade definitely kept the other plants healthier.

[Silas_Sancona]

5 hours ago, palmsOrl said:

I have read that the sand surface in some deserts can reach 160-180F, though I doubt the full root-zone of anything but seedlings could experience anything close to that.

Wouldn't doubt it. Pavement can easily reach 160F+ here.  The high soil temps are one big reason most plants start below something else, ie:  Saguaro /# of other cacti typically germinate / start out life in the shade of a Nurse tree or larger bush.. Seedlings wouldn't survive one summer out on an open area, fully exposed to the sun. Over time, they will out grow their shelter and into more sun / heat.

At the opposite end of the spectrum, there are several plants which will only germinate when soil temps are hot.. Perennial Devil's Claw,  Sacred Datura, and Summer Poppy ( Kallstroemia grandiflora ) are good regional examples. While the first two produce a deeper root system which likely escape the hottest layer of the soil,  Annuals like Kallstroemia ( ..and related Tribulus, Puncture vine ) Annual Devil's Claw, and Portulaca ( Purslane / Moss Rose ) root close to the surface where no doubt the soil temp is likely running 100F+ Of course, as these plants spread out, overall mass of foliage/ stems, etc will help cool the soil around them.

Edited June 3, 2019 by Silas_Sancona
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[pj_orlando_z9b]

10 hours ago, Silas_Sancona said:

Wouldn't doubt it. Pavement can easily reach 160F+ here.  The high soil temps are one big reason most plants start below something else, ie:  Saguaro /# of other cacti typically germinate / start out life in the shade of a Nurse tree or larger bush.. Seedlings wouldn't survive one summer out on an open area, fully exposed to the sun. Over time, they will out grow their shelter and into more sun / heat.

At the opposite end of the spectrum, there are several plants which will only germinate when soil temps are hot.. Perennial Devil's Claw,  Sacred Datura, and Summer Poppy ( Kallstroemia grandiflora ) are good regional examples. While the first two produce a deeper root system which likely escape the hottest layer of the soil,  Annuals like Kallstroemia ( ..and related Tribulus, Puncture vine ) Annual Devil's Claw, and Portulaca ( Purslane / Moss Rose ) root close to the surface where no doubt the soil temp is likely running 100F+ Of course, as these plants spread out, overall mass of foliage/ stems, etc will help cool the soil around them.

I remember going to Death Valley. The air temp was 116F. When I knelt to the ground the cement was so hot I almost burned my knee. I didn't do that again!

[Silas_Sancona]

7 minutes ago, pj_orlando_z9b said:

I remember going to Death Valley. The air temp was 116F. When I knelt to the ground the cement was so hot I almost burned my knee. I didn't do that again!

Heat here is no joke for sure.. One of the local news stations did a story last year regarding surface temperatures around the valley last year.. While paved /concrete surfaces weren't a surprise, the people doing the research measured temps on various equipment at a couple playgrounds also and showed readings of 170-190F, even on slides, etc made of plastic which were lighter in color.. A little surprised by that myself.  Phoenix also enacted a ban on taking your dogs hiking in all the parks when air temps exceed 100F.. No clue why, but there are people here who seem to think their 4 legged hiking companions aren't effected when it is that hot out.. Paws burn a lot easier than human skin can. 

[Merlyn]

On 6/1/2019 at 6:28 PM, Silas_Sancona said:

Sounds crazy but our intense sun / high soil temps this time of year can even torch various Cacti and Agave, hence why ..if you toured some place like Desert Botanical in June, July,  and/or August, you would see shade cloth slung over numerous things in various displays there.. On top of that, watering certain stuff when air / soil temperatures are this hot can cook it just as fast as rot that can happen under cold / wet  soil / air temp conditions in winter. Outside this time of year, nearly perfect growing conditions for 99% of things..

This is very true, in May we had a borderline drought and several 95+ days with no clouds.  I had about 10 agaves in black pots in the backyard, and half of them were fried in the sun.  Then it rained one day and they got edema and rot.  Fortunately there were no rare plants and most will recover, but my agaves in the ground about 20 feet away were all fine.  Being in the black pots in the sun really torched them and dried out the soil bad.

[Silas_Sancona]

43 minutes ago, Merlyn2220 said:

This is very true, in May we had a borderline drought and several 95+ days with no clouds.  I had about 10 agaves in black pots in the backyard, and half of them were fried in the sun.  Then it rained one day and they got edema and rot.  Fortunately there were no rare plants and most will recover, but my agaves in the ground about 20 feet away were all fine.  Being in the black pots in the sun really torched them and dried out the soil bad.

Be glad you ( ..and the rest of Florida ) don't experience the same degree of extended summer season heat / drought we have each year..  And don't ever wish for it,  Embrace the humidity, sweat and all lol.

When i made a late summer visit to Desert Botanical after moving here in 2016, i wasn't expecting to see what spending an entire summer in full sun combined with extremely low humidity through most of the season can do to various Agave and Cacti here, vs how  specimens of the same plants were doing under high tree canopy / tucked among various perennials/ low shrubs, or under shade cloth there at the garden / other public gardens in Tucson, in yards / commercial landscapes, or at the nursery i worked at. Remember overhearing someone asking one of the garden docents why several cacti in a nearby bed were covered w/ shade cloth, and being completely surprised by the answers.  Until monsoon season arrives, summer here is tough on pretty much everything, especially anything exposed to full sun all day that sits close to the ground.

Have a "Huntington" truncata which has been slowly closing itself up a bit as it gets hotter.. Same with another A. parryi clone i planted out in the front yard. On the other hand, i have a few.. much smaller, young parryi, a couple ovata, and a pair of Dragon Toes ( A. pygmaea/ seemanniana ssp. pygmaea ) sitting in the shade house, in pots, pretty small pots in fact.. who have handled the elements through the summer pretty well under a single layer of shade cloth.. Others, specifically green -leaved sp. i have sitting where they get filtered sun until about 10-11am this time of year. A. chazaroi, and a species from Cuba i have sit under the patio and only get filtered sun late in the afternoon.

'Couple years ago, we had several nice Chazaroi at the nursery i worked at which did fine in sun until about now.. About the time we had a week of 109-117F temps, i ended up sick.  When i returned, 2 weeks later, most were badly sunburned because no one had moved them to a spot with more shade.  Wasn't happy.. Also lost several 10 gal sized Trichocereus specimens that summer also.. To the sun. 

[kinzyjr]

5 minutes ago, Silas_Sancona said:

Be glad you ( ..and the rest of Florida ) don't experience the same degree of extended summer season heat / drought we have each year..  And don't ever wish for it,  Embrace the humidity, sweat and all lol.

When i made a late summer visit to Desert Botanical after moving here in 2016, i wasn't expecting to see what spending an entire summer in full sun combined with extremely low humidity through most of the season can do to various Agave and Cacti here, vs how  specimens of the same plants were doing under high tree canopy / tucked among various perennials/ low shrubs, or under shade cloth there at the garden / other public gardens in Tucson, in yards / commercial landscapes, or at the nursery i worked at. Remember overhearing someone asking one of the garden docents why several cacti in a nearby bed were covered w/ shade cloth, and being completely surprised by the answers.  Until monsoon season arrives, summer here is tough on pretty much everything, especially anything exposed to full sun all day that sits close to the ground.

Have a "Huntington" truncata which has been slowly closing itself up a bit as it gets hotter.. Same with another A. parryi clone i planted out in the front yard. On the other hand, i have a few.. much smaller, young parryi, a couple ovata, and a pair of Dragon Toes ( A. pygmaea/ seemanniana ssp. pygmaea ) sitting in the shade house, in pots, pretty small pots in fact.. who have handled the elements through the summer pretty well under a single layer of shade cloth.. Others, specifically green -leaved sp. i have sitting where they get filtered sun until about 10-11am this time of year. A. chazaroi, and a species from Cuba i have sit under the patio and only get filtered sun late in the afternoon.

'Couple years ago, we had several nice Chazaroi at the nursery i worked at which did fine in sun until about now.. About the time we had a week of 109-117F temps, i ended up sick.  When i returned, 2 weeks later, most were badly sunburned because no one had moved them to a spot with more shade.  Wasn't happy.. Also lost several 10 gal sized Trichocereus specimens that summer also.. To the sun. 

Certainly makes me happy I'm here where the monsoon is in full swing.  I'll be heading to LV in the fall.  Definitely glad it won't be the summer.

[Silas_Sancona]

6 minutes ago, kinzyjr said:

Certainly makes me happy I'm here where the monsoon is in full swing.  I'll be heading to LV in the fall.  Definitely glad it won't be the summer.

Las Vegas can still be hot in the fall, depending on when you're making the trip.. though yea, lol.. likely not nearly the scorch fest it will be until at least mid September out here.

[kinzyjr]

1 minute ago, Silas_Sancona said:

Las Vegas can still be hot in the fall, depending on when you're making the trip.. though yea, lol.. likely not nearly the scorch fest it will be until at least mid September out here.

My trip will be around Thanksgiving.  It should be relatively comfortable both here and there at that time.  We'll see.

@Merlyn2220

I noticed some decline in plants that were in black pots exposed to sun as well.  Predominantly affected were some of my Roystonea regia.  I tossed one in the ground and it seemed to acclimate and push out new growth almost instantly - similar to your experience with the ones in the pots declining and the one in the ground doing just fine.

[pj_orlando_z9b]

3 hours ago, Silas_Sancona said:

Las Vegas can still be hot in the fall, depending on when you're making the trip.. though yea, lol.. likely not nearly the scorch fest it will be until at least mid September out here.

Deserts are interesting to me. I've been to Vegas in every season. I was there when it was 114. It was just hot as hot can be. But get in the misters or out of the pool and it feels just perfect. I was there in Jan and it was 40s and 60 mph winds. I was freezing. There are some amazing climates on this earth to see such seasonal swings!

[Silas_Sancona]

Seeing that today is supposed to be the hottest day of the year ( thus far ) took some quick, crude readings around the yard..  Air Temp, at least according to  WX stations on Weather Underground closest to the house were sitting between 110 and 116F at 4:18PM MST.  Used the same thermometer i'd used before. Didn't take pics.. maybe next time.

Open ground in the sunniest part of the yard, with some residual organic cover left on the surface from this years' winter grass: 136F

Nearby, where the ground is covered w/ darker colored stone: 140F

Soil directly under the Mesquite, covered with 3" of light colored decomp. Granite: 110F No direct sun all day. Area is shaded by the tree , Shed, Block walls.
Average soil temp of potted stuff placed there: 100F

Measured temps in a few other things that sit where they're exposed to more sun, situated further out from under the Mesquite/ shed/ walls. They also sit on decomp. Granite.  Shaded by tree canopy most of the day, roughly 11am- 6pm before it sets over the block wall.  Average temp was about 5F warmer, less in stuff i'd put Mesquite mulch in / whitewashed the outside of the pots.


On the outside of the patio. Faces directly into afternoon sun until shade from the back wall reaches them ( about 6:00pm or so atm) :

Coccothrinax in regular,  wide 3 gal black plastic container, outside not whitewashed/ top of surface is mulched however:  137F.
Large Bursera microphylla specimen in 10 gal Clay pot next to it: 140F


Shade Alley: Average of everything i measured there was 100F. No direct sun all day. Overhead cover of 2 layers of shade cloth. Shaded by the shadehouse itself after 2:00 PM until sun sets behind back wall.


Plumerias, pots topped with Mesquite Mulch. Stems / outside of pots all whitewashed. Single layer of shade cloth overhead. Sit on plastic racks roughly 3" above the concrete pad. Filtered sun all day. In 3-5gal pots:  Average of 105F.   Did notice some foliage burn on one plant where  wind had opened gaps in the shade cloth overhead.


 

Edited June 13, 2019 by Silas_Sancona
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[Hillizard]

  With real estate and with plants... it's always important to consider "location. Location. Location."