Insulating garden beds from the HEAT

So we moved to a new place, it's a rental, and there are some garden beds installed by the previous tenant in the backyard. Since we are in mid Texas, raised beds are the worst idea for the hot and dry climate here, because the sun beats on the beds from three sides, kills all the microflora, dries them out, etc. So I normally do beds that are level with the ground or even slightly below to preserve moisture and cooler temps in the summer (as a result I usually have much better harvest in the toughest months than most people). I don't wanna put in too much work and resources into this property since we are renting, but digging up the beds and making them level with the ground is a possibility I will probably consider. For now, what can I use to insulate the pallet wood beds from the heat in July and August that's cheap?

I should mention I'm a short and weak girl but I can swing a hammer.

I'm in DFW, so similar situation.

I think people under-appreciate how hot and dry our garden beds get here in the mid south during summer. On clear summer days, when humidity is low, during a long dry spell, I've measured the foliage getting up to 140-150 degF. When its windy, plants dry out fast.  Plants die after that double whammy. Rain water stored in barrels runs out fast, and I don't want to pay a lot for irrigating using city water, so much of my garden becomes somewhat fallow during the hottest parts of the summer.
The best areas turn out to be:
1.  Those that had some uncontrolled weed growth in late spring, keeping the sun off the soil.
2. Wherever I "over did it" with the mulch.

My learning from this is to try to acquire even more free mulching materials like bagged leaves from the neighborhood, and to keep the soil covered at all times. With the recent heavy winds, a lot of mulch leaves escaped until I laid down some branches to hold them down as a windbreak, like a snow fence for leaves.

To finally get to your question - protecting raised beds - if you also have access to free mulch like leaves or wood chips, along with branches and wood scraps, I would lay that down between the beds ridiculously high until it is protecting and insulating the raised bed sides. It will act as a rain collecting sponge for spring rains, and allow worms and soil life to find a refuge from both flooding/drowning and heat later in summer.

Meanwhile keep the soil surface of the beds covered in living mulch at all times. The lambsquarters grow pretty well even in the heat if they get just a little water. Plant under and around them, clipping off the thickest and tallest before they outcompete your crops. Be sure to avoid letting them go to seed too much, or every bed will become a seed bank of weed seeds.

My ideas here are focused on what's free and easy. For your particular situation, more info on your soil type, location (rural or suburban, etc), garden size, type of plants you hope to grow, etc... that would help to tailor the solutions to your problems.

Duh... almost forgot the other major effort for my garden this year - cardboard.

Its an excellent insulator, perfect for your application. If its plain and free of tape and plasticky gunk, its a relatively natural material, and the glue is super-worm-food.

I'm laying it down in layers in the garden pathways, alternating with leaves, clipped weeds, and enough small branches to keep the wind from lifting it into the neighboring yards.

I've got a few experimental beds of coarsely shredded cardboard with leaves, grass clippings, etc as a Ruth Stout style bed to plant early potatoes by burrowing the seed spuds down to the soil level inside the mulch.

The obvious answer is shading fabric, but it's made of plastic. I'd say it's quite cheap.
The less obvious one is casting a shadow with a big shrub or a small decidious tree, but I don't think you have time for that, especially if you think you will be moving later.

We know of a garden that mulches everything with flat stones in combination with shrubs. The vegetation prevents direct sun over the stones, and the stones prevent evaporation.

I would also ask about "walls" for the raised beds, maybe even with something like sweet potato growing on them? That way it provides some shade and maybe less moisture loss to wind. Does that lead to more pests?

After painting the raised bed side-boards with flat white outdoor latex paint (watered slightly to make a wash), my beds here in New Mexico came to life. Huge impact. The flat white paint reflects the heat rather than absorbing it and frying the plants. I have also used the flat white paint on ~6" river-stones both to reflect the heat and serve as mulch keep the moisture in the bed as the seedlings are starting. If you don't want to paint, you could try surrounding your beds with white sand-bags or even white Agribon. For tomatoes, sew Agribon into "pillow cases" and slip them over your cages. Works like magic!

     Howdy Tatiana,


       This is a topic close to my heart and timely for the projects I'm working on this growing season. I have always thought that raised garden boxes are a vernacular that comes from the East coast and similar climates. Raised beds to my mind are used for getting the root crown out of too much water and to drain that water away. Of course they are easier to harvest from, however that was always secondary consideration, or so it is for me. As you know, we who live in hot, drier areas in Summer do need do things differently than our friends in other climates. And we can share that.
       To that end, and dispensing with the preamble, here's what I think so far, and this is from Mollison and others: 1. Begin with shade. Shade cloth or the ever-present ramada which appears in many arid cultures. 2. Mulch, which from my experience isn't as powerful as shade, but can make great deal of difference. 3. If you have the potential change the aspect of your beds, that also can achieve quite a bit. Of course, this difference shows most where the margin of life is at its slimmest. 4. Change the width of the sides of the raised bed on the South and West sides.
        Plants are a bit like us, I know in the heat of Summer I don't stand in the sun, I seek shade. Of course there are people who love the heat just like some plants and they can stand it. One last point, the heat generated from the sun can kill roots to a depth of 8"  when temperatures of the soil reach 100 deg. or more. Not so common in some climates, common in others. Those are my thoughts, I hope they provide a good point of orientation for your decisions. Good luck!


      Thomas,
     
       Mitama Farm

Thomas Agresti wrote:

     Howdy Tatiana,


       This is a topic close to my heart and timely for the projects I'm working on this growing season. I have always thought that raised garden boxes are a vernacular that comes from the East coast and similar climates. Raised beds to my mind are used for getting the root crown out of too much water and to drain that water away. Of course they are easier to harvest from, however that was always secondary consideration, or so it is for me. As you know, we who live in hot, drier areas in Summer do need do things differently than our friends in other climates. And we can share that.
       To that end, and dispensing with the preamble, here's what I think so far, and this is from Mollison and others: 1. Begin with shade. Shade cloth or the ever-present ramada which appears in many arid cultures. 2. Mulch, which from my experience isn't as powerful as shade, but can make great deal of difference. 3. If you have the potential change the aspect of your beds, that also can achieve quite a bit. Of course, this difference shows most where the margin of life is at its slimmest. 4. Change the width of the sides of the raised bed on the South and West sides.
        Plants are a bit like us, I know in the heat of Summer I don't stand in the sun, I seek shade. Of course there are people who love the heat just like some plants and they can stand it. One last point, the heat generated from the sun can kill roots to a depth of 8"  when temperatures of the soil reach 100 deg. or more. Not so common in some climates, common in others. Those are my thoughts, I hope they provide a good point of orientation for your decisions. Good luck!


      Thomas,
     
       Mitama Farm

Living in the desert of Southern Utah I think Thomas is giving good information here.  Would it be possible for you to dig down a bit in the center of your raised beds and plant your veggies and flowers closer to the ground, but leave the dirt mounded up on the sides?  I know it would be less growing area but that dirt and mulch would act like insulation and your plants roots would reach into the ground for cooler temperatures and maybe more moisture.

Also, you could consider using foam board insulation on the outside of the walls on the raised beds, then cover that with low cost or repurposed wood to make it look nice.  You could also add a top plate of wood extended out wider than the side walls and the overhang will provide some shade to the ground around the raised beds.  Depending on the height of the beds it may also give you a better seat for weeding and tending to the plants.

Are the raised beds in the lawn or grassy area?  Or are they surrounded by bare dirt?  If dirt be sure to mulch around the beds to help keep the ground moist and cool, and to keep weeds down.  If grass, water in the evenings just before sunset to cool the area and allow the water to soak into the raised bed and the surrounding area.  But, as others mentioned, shade is a good thing on the hot, dry summer days.  Solar shades come in a variety of shapes and different sizes. Just make sure they are tied to something solid or the wind will take them for a ride.

Interesting thread. I'm in South Carolina, and have the same problem with raised beds due to most of our summer days being in the upper 90sF with long dry spells. I tried a few raised beds, but have been switching to double dug hugelkultur swale beds, which are bordered, but not raised. Tatiana, I know that doesn't help you, since you're renting, but this other idea might.

What I wanted to share, though, was an Australian gardener whose blog I follow, Outback Tania. Her garden is entirely in wicking pots in an enclosed area under shade cloth. It produces beautifully. Out of respect for her copyright I can't post photos, but you can see how they set her garden up in this blog post ->"New View of the Veggie Patch".

I grew up in Bermuda which was very hot and humid in the summer and all the old-timers used to have wooden slat or lathe houses to grow through the summer months. I remember visiting a few as a child and they they were very beautiful and effective.  It was always cool inside and there was usually a breeze.  They also keep the moisture levels up if there was a dry spell. This is the best picture I can find of what they used to look like:



I have dreamed of building one myself out of scrap wood if I ever get to live in a hot climate again.  

Perhaps mini slat house would work over raised beds.  

   

I don’t really have anything to share, but wanted to say thank you to everyone who has shared!

I currently have raised beds I’m just kind of living with until we move.

But then you also have people like my friend who really wants raised beds because of her aching back- but we live in central Texas!

On my new property I was thinking of building terraces... would the same issue with raised beds be true for the raised part of the terrace?

I live in southern AZ and deal with the same issue.  I don’t rent but one thing I found at my last place(raised beds but sunken below grade).  Maybe you can dig out the paths a bit, lay down a bunch of mulch.  Whatever you have.  I used Woodchips.  When it rained the area filled up, the beds drained but the Woodchips soaked it all up.  I also grew sweet potatoes.  Though I didn’t get much in the way of potatoes because I didn’t irrigate enough, the vines were everywhere and did a great job of shading the ground as a ground cover and I let them trellis up 4x8 remesh fixed to emt conduit frames.  I also had it on drip and would irrigate for 5 mins every 2 hours or so during the heat of the day just to keep the soil moist.

I don't know if it is something you have in the US, but here in France you can get any number of these, in stores and markets, they are usually discarded or given to you to transport your groceries home:

https://www.hellopro.fr/clayettes-2015611-520582-produit.html

I stand two of them on their end above my seedling when the temperature gets too high - they hold each other up into a steeple sort of structure.  It gives a dapple shade and protects the smaller crops from the worst of the heat. It works well for small crops and it's free but for taller/larger ones, I don't know, maybe, a few sticks and large cardboard pieces or an old bed sheet???

South Carolina is not Texas, but it get dry here too.
That is just one of the reasons, I use Robert Rodale's raised beds instead of wood, tin, concrete or plastic.
Mr.Rodale, one of the Fathers of organic garden double dug & used a low arc to make his raised bed, with no walls.
That leaves very little to heat up, a little mulch & some water will win the day.
Tomatoes do not like a lot of heat, but young plant seem to do better, so I replant so I will have fruit in the cooler Fall.

I am getting ready to build a bunch of raised beds for my new garden. (have to wait a bit as currently am enjoying the sun and sea on St Croix visiting family here).

I have a lot of 2 inch foam board left over from when we insulated our trailers from the cold a year ago when we were building our homes, (one of my sons bought property next to us and we had a bit of a trailer park)

The foam board seems like a good idea to help insulate the raised beds.  Plenty of room inside the framework of the bed.  I also have a few shade cloths that I am planning on using.

We are considered high desert and after 2 years on this property I can see that everything mentioned so far will be put to the test by me in my new garden.

Mulching will definately be a priority for us.

Thanks everyone for the great idea's !!

In my desert garden in Tucson the summer heat would cause insti-bolt. I had shade netting domed over it in a tunnel, but still, when the temps popped over 100F and the hot desert breeze washed over, it was like raising plants in an oven.

I increased the water, on the drip system timer, but….
…Up north you use a greenhouse in the winter. Down here, the summer generally requires it. We can start with an earlier spring, racing before the summer heat.

With some shade, the soil temperature hasn’t been an extreme issue. As a kid in New Mexico, we’d visit White Sands National Monument. The white sand reflected the heat, but ankle deep it remained cool, even refreshing. I’ve often considered spraying shadecloth white from that lesson, but have yet to try it. Has anyone beat me to that experiment?

John wrote: With some shade, the soil temperature hasn’t been an extreme issue. As a kid in New Mexico, we’d visit White Sands National Monument. The white sand reflected the heat, but ankle deep it remained cool, even refreshing. I’ve often considered spraying shadecloth white from that lesson, but have yet to try it. Has anyone beat me to that experiment?

I see you are asking the important questions.

I have absolutely no experience with shade cloth (though it sounds like I should get some- living in Texas)
However, it would make sense white would be better. Just like how having a light colored roof makes for a cooler attic than dark shingles or metal.

The only thing that I know will help is to have morning sun and afternoon shade.

Maybe some sort of tunnel would work with a constant misting system to cool the air as they have tried in some restaurants.

A drip system doesn't cool the air though keeping the soil moist might.

Sarah Elizabeth wrote:

I grew up in Bermuda which was very hot and humid in the summer and all the old-timers used to have wooden slat or lathe houses to grow through the summer months. I remember visiting a few as a child and they they were very beautiful and effective.  It was always cool inside and there was usually a breeze.  They also keep the moisture levels up if there was a dry spell. This is the best picture I can find of what they used to look like:



I have dreamed of building one myself out of scrap wood if I ever get to live in a hot climate again.  

Perhaps mini slat house would work over raised beds.  

   

 The slat houses are beautiful! I'm in Oregon but I like the idea for the hottest months. Maybe even something without sides. A half sheet of lattice on legs could work and could be placed wherever its needed! Thanks for sharing!

I manage a 1/2 acre vegetable market garden in Oklahoma for a non profit that has a pretty low budget for inputting materials.
The first year our tomatoes, cucumbers, peppers, beans etc...all stopped producing from July 1st-Sep 1st because the temperatures were so high and the plants had no protection from the sun. I wanted to put shade cloth over the entire half acre but the price would of been wayyy to high.

Last year I experimented with growing the shade for those summer crops with Sunn Hemp. And it was incredible! In May I would cut a little furrow on the very outside edge of the beds (our beds are 3 feet wide), sow the sunn hemp seeds in the furrow pretty thickly, then rake the soil back over it. It germinates crazy fast, even without much moisture. And then it would grow crazy fast! I would just chop and drop however much to get to the amount of shade I thought was best.



-So I ended up getting the shade I needed at a way cheaper price. And I didn't have to build a structure to put the shade cloth on. And I don't have to find somewhere to store the shade cloth when its not hot.
-It became a constant source of green mulch to lay around the summer crops (the plants I chopped and dropped kept growing back super fast so I was able to rechop them every other week).
-It's a nitrogen fixer!
-The plants I didn't chop and drop make these really pretty yellow flowers that would attract birds and pollinators.
-We had troubles with Bermuda grass in the walking paths and it couldn't get past the thick wall of sunn hemp into our garden beds!
-The tap roots go down really deep and I suspect bring up water and nutrients to share with the vegetables rather than competing.
-it's an annual so after the first frost it dies and that big root system decomposes over the winter and helps decompact and feed the soil.


I was super happy with it and I'll be experimenting more this year. I imagine if it's a hotter climate than Oklahoma I would plant a row down the middle of the bed as well as the borders for extra shade in the very middle of the day.

Thank you for this big time!

I believe you may have just solved about 5 excess heat and sun problems I've been puzzling over for a while...not to mention the added benefits.

So, I went looking, and found a resource for Sun Hemp bulk and many other very interesting and different cover and other crops:

https://petcherseeds.com

He even has ancient peruvian corn as it was before it was Zea Mays corn:

https://petcherseeds.com/collections/spring-summer/products/teosinte


The only other I found in small enough quantity were on Ebay, and a good bit more expensive, but small quantities of 300 seeds available if that's of interest.

The ebay source does have a dwarf version called Tropic Moon.

Again, many thanks.

That Petchers site you linked to says sun hemp does not go to seed in Alabama because it gets cool enough before they seed. Any idea where I can get more information on this?

It would be awesome to plant some on my land before I move to help build the soil but I don’t want it taking over. I’m a good bit south of Alabama (Central Texas) so I bet it would go to seed here, but it would be nice to read more on it.

Dave Bross wrote:Thank you for this big time!

I believe you may have just solved about 5 excess heat and sun problems I've been puzzling over for a while...not to mention the added benefits.

So, I went looking, and found a resource for Sun Hemp bulk and many other very interesting and different cover and other crops:

https://petcherseeds.com

He even has ancient peruvian corn as it was before it was Zea Mays corn:

https://petcherseeds.com/collections/spring-summer/products/teosinte


The only other I found in small enough quantity were on Ebay, and a good bit more expensive, but small quantities of 300 seeds available if that's of interest.

The ebay source does have a dwarf version called Tropic Moon.

Again, many thanks.

Thanks for that link! That corn looks really cool. I've been trying to figure out how to grow more forage for our pigs, chickens, and ducks and that looks like a really cool addition.


There's a local seed store in our area that we buy the sunn hemp seed from in 50 pound bags and it's pretty cheap.
50 pounds will go really far, especially if your just using it on the borders of beds for shade.

Here's where I've also looked at buying it and other cover crop seed from:

https://hancockseed.com/collections/best-sellers/products/sunn-hemp-seed?_pos=1&_sid=3d8e02c16&_ss=r

Cindy Baker wrote:

   The slat houses are beautiful! I'm in Oregon but I like the idea for the hottest months. Maybe even something without sides. A half sheet of lattice on legs could work and could be placed wherever its needed! Thanks for sharing!

Thanks Cindy.  I really like your lattice on legs idea as it can get moved around as needed.  Portable shade.

I live in Northern California and we see high temps all summer long.  If it rains in the summer we all run outside and do a little happy dance.  I like raised beds, other wise my garden is over run with Bermuda grass.  I have been converting my beds to hugel beets, and use mulch. This has made a big difference.
I was excited about the sunn hemp, thinking I could plant it on the west side to give a little relief from the brutal afternoon sun.  Unfortunately I read the seeds are quite poisonous to chickens, and my chickens will gobble up what ever they can get through the fence.  It's a great idea though, I just need to find an alternative. To bad because the sunn hemp has so many benefits.  Good luck to you. Happy gardening.

Jen Fulkerson wrote:Unfortunately I read the seeds are quite poisonous to chickens, and my chickens will gobble up what ever they can get through the fence.  It's a great idea though, I just need to find an alternative. To bad because the sunn hemp has so many benefits.  Good luck to you. Happy gardening.

You might ask a company that sells it if they think it would go to seed in your climate. Supposedly it needs a pretty specific climate in order to go to seed.