18 gal earthtainer heat problems: 99 deg even with sunshade

[Vespertino]

My balcony hovers in the low to mid 100's daily thanks to the radiant heat island effect. As a result the temp inside my earthtainers is 99 degrees this morning, even with a sun shade. I stuck a therma-pen into the soil to see what the reading was.

My earthtainers are smaller than the standard 31 gallon, I made two 18 gallon ones since my balcony is really small. I'm guessing in an environment like mine where the temps stay high over 100 for most of the day, the 18 gallon ones heat up much faster since they're smaller, and perhaps more prone to swings in temperature than a 31 gallon would be.

My sungolds are just fine, but my Brandywines have been noticeably suffering : major BER (cal mag didn't fix it), stunted growth at the top, fruits that were set grow very small, and this week I noticed little bumps forming on the lower stem- all signs of root stress as far as a newb like myself tell. The BER has subsided since I added the sunshade on the earthainer, but no improvement otherwise.

While I'm inclined to blame the heat warming up my 18 gal 'tainers, I'm a novice so I'm wondering if it might be other factors?

1) Maybe the brandywines need more root space- while a 31 gallon 'tainer can hold two, perhaps and 18 gal 'tainer is better suited for one plant? I have 2 brandywines in the 18 gal 'tainer, maybe the roots are crowded?

2) I'm using Lady Bug Brand square foot mix in the 'tainers. They use coco coir instead of peat. Too much moisture retention? I'm not sure about this, since it's an issue with the brandywines in one earthtainer, while my sungolds in the other seem perfectly fine. Sungolds are known for being more heat tolerant, so if it were a moisture problem with the mix wouldn't I be having problems with the plants in both earthtainers?

3) Maybe it's just the Brandywines themselves? Maybe the size of the earthainer doesn't make a difference? Perhaps they just don't grow well in earthtainers where the summers are as hot as mine (North Texas). Perhaps I should have gone with a variety more suited for the weather, like my sungolds are.

Anyway I think my branywines are kaput. I have BBB and SCP plants growing in pots to replace the BW's in August for the fall season.

[amideutch]

I think your major problem was that you planted out too late for your location. Most folks down in your neck of the woods have already harvested their maters and are getting ready or already have started seedlings for their fall crop.

I remember when I enlisted in the Air Force we flew into San Antonio for basic training just about this time in July and landed around midnight. When we got off the plane it was like a blast furnace. Didn't do many activities outside the whole time I was there do to the heat.

Ami

[rwsacto]

Hi,

Because you are on a balcony, you do not get the benefit of ground contact cooling the reservoir. Well shaded containers will be closer to the average air temperature.

I use 18 gallon earthtainers also. My first line of radiant heat defense is to build a wooden screen 2 ft high out of fence material positioned to the west of the swc's.

Second, I use white compactor bags as the mulch cover. If you slit the bottom and one side of the bag, you have enough material to cover the top and drape it over and around three sides of the container to reflect the sun. I let it hang down so there is air space between the cover and container wall.

My cover is not "air tight", just reduces evaporation and reflects sun. Small bark in the top of the swc also helps insulate radiant heat from the top. The aesthetics of the white plastic over the side may not be pleasing for everyone.

HTH
Rick

[Vespertino]

Originally Posted by rwsacto

Hi,

Because you are on a balcony, you do not get the benefit of ground contact cooling the reservoir. Well shaded containers will be closer to the average air temperature.

I use 18 gallon earthtainers also. My first line of radiant heat defense is to build a wooden screen 2 ft high out of fence material positioned to the west of the swc's.

Second, I use white compactor bags as the mulch cover. If you slit the bottom and one side of the bag, you have enough material to cover the top and drape it over and around three sides of the container to reflect the sun. I let it hang down so there is air space between the cover and container wall.

My cover is not "air tight", just reduces evaporation and reflects sun. Small bark in the top of the swc also helps insulate radiant heat from the top. The aesthetics of the white plastic over the side may not be pleasing for everyone.

HTH
Rick

thanks for the advice, I was using black plastic bags and cedar mulch on top. I'll remove all of that stuff and replace it with a white bag and loose the cedar mulch, anything would help at this point. I haven't lost more fruit since I put on a shade last month, but the plant still seems really stressed. Poor thing.

[Balr14]

I use Earthboxes (19.3 gallons) and the temperature on my patio is typically mid 90s to 100+ in July and August. I fill the reservoirs in my containers once a day. The plants grow like crazy and I get tons of tomatoes. This picture was a week ago. The plants have since grown at least another foot.

[Rockporter]

Bubble wrap on the outside of the container would probably help with the heat by insulating the outside of the box. A white cover is definitely needed in the hot heat. What about hanging a white sheet or white sun cloth on the wall behind the plants to help absorb some of the heat? Just ideas.

[rnewste]

Wrap a section of bamboo or rattan around the outside of the container to help shade it.

Raybo

[fishtrap]

i posted this in another thread, but i will post it here also. This is my second year with 'tainers on a black rubber garage roof. Both years the plants have basically struggled and quit in July when it heats up - ber, blossom drop, leaf curl, stunted growth. I have meticulously followed directions this year and have flushed with Fox Farm Sledgehammer. I thought last year it might have been salt build-up. While they are up on wood leveling platforms a couple of inches, i am thinking now that the heat is too much for the roots. It is 95 ambient today, a bit over 100 ambient on the roof, and 120 sitting directly on the rubber. I just went to Lowes and purchased some 24" Reflectix double bubble reflective wrap and put a skirt on each 'tainer. Bought some cheapo nylon rope and some bungees to hold it on. We'll see if that helps.