There would have had to have been a lot of compost/organic matter decomposing to generate a lot of heat. It's not uncommon for compost piles and mulch piles to heat up to the point of smoldering if left unturned. However, if these plants were really dry, there would be no decomposition in progress. Also, heat from the sun is usually required to cause this. There has been several cases of so called spontaneous combustion of plants, but usually the plant is noted to be dead. A live plant doesn't burn so well. I don't know if I'm sold on the explination here, unless there was a pile or barrel of compost in the shed.

Joe

This happened at my home on Sunday, June 5, 2011. We have several large ceramic pots on our deck - four of them are grouped together containing strawberry plants. I saw smoke while looking out my bedroom window...It was coming from one of the strawberry plants. The plant was "crispy" when the night before it was - or seemed and felt - extremely healthy. The other pots were not affected. The soil is very natural - from the woods on our property - with some compost material added - egg shells, peanut shells, garlic, etc.... I had noticed a "burning" smell for about a day and a half but I couldn't tell where it was coming from until I saw the smoke. Very Scary! So very glad I was home!

A very good reason to save organic methods for the garden, and go with a more inorganic approach for containerized plantings... avoiding imbalance and overly fast decomposition leading to too much generated heat.

Usually, you only hear of this sort of thing happening in a silo, or large barn where hay has been baled and stacked while too wet.

Interesting Wikipedia article on the subject.

Here is a link that might be useful: /Spontaneous combustion

This just happened to me on San Juan island,Washington. We had quite a few 80 degree days then a little rain. I read that water can act as a catylist in this situation. The pot had fertilized soil in it and sat under an over hang so it didn't get much water. As you can see from the picture this was a very close call to wake up to a smoldering flower pot this morning.

"go with a more inorganic approach for containerized plantings"

Like what? Peat and pine are most certainly organic.
I've seen peat burn, hard to put out.

Fir bark (un-composted) doesn't break down that quickly as a medium ingredient... and the other ingredients I employ are coarse perlite, granite chips, turface... others might be lava rock chips, pumice, DE chips, cherry stone, etc...

That's a more inorganic approach to building container medium. I use such a mix because it allows me a lot of leeway for error in watering... and it allows my plants of choice to remain in the same medium, undisturbed, for at least 2 years... sometimes 3... before I have to refresh the medium. I grow mainly tender amaryllids and other tropical ornamentals.

Medium only serves the purposes of support for the plant, a catalyst for moisture and nutrition, and also as a catalyst for the exchange of gases and oxygen at the root zone. Therefore, a heavily organic soil is not necessary to use within the confined space of a container... which differs greatly from a garden setting, anyway.

It's next to impossible to duplicate Mother Nature's methodology within a pot, and next to impossible to maintain the same balances of everything that occurs in Nature, such as the vast army of living things, microscopic and otherwise... like worms, nematodes, fungi, insects, bacterias, etc... that work in harmony to break down organic matter into usable food for plants, and help keep the soil aerated. Therefore, I save organic gardening for the gardens, and employ a more inorganic tact for container growing.

Doing so allows me to control the moisture amount, the fertilizer, the micro-nutrients... and not have to worry about the fast breakdown of organic matter, imbalanced PH, perched water tables, poor drainage, an inability to properly exchange gases and fresh oxygen - which the roots require for good health, or try to maintain an exact duplicate of the masses of life underground... etc.

Most of the medium I use is larger particled, highly aerated, sharp draining... closer to a bonsai or orchid type of medium.

There are other slightly more organic medium mixes... such as the 511, as it's called, which contains fir bark, coarse perlite, peat, and some growers use other larger particled ingredients, as well... what a grower uses depends mainly on what's locally available, what they're growing, how long it must remain in that medium, their individual climate and environment, the amount of time devoted, their expectations of optimal plant growth, among other variables.

It's not so much the exact ingredients or their ratios... it's understanding the concept of such mediums that's most important... and then adjusting it to fit your individual situation.

A grower could actually go purely inorganic by using any of the inorganic items I've listed... keeping in mind the purpose a medium really serves... plant support, catalyst for food, water, and the exchange of gases and oxygen. It all depends on how much time you want to devote to watering, feeding, and caring for your plants of choice.

Hydroponic growers use strictly inorganic material as the medium... so we know it can be done.

The bottom line is... it's not a necessity to use organic matter to grow plants successfully... and in fact, I advise against trying to duplicate Nature in the confined space of a pot.

"employ a more inorganic tact for container growing."

I have been doing this for 35 years myself. But the last few years I have been experimenting with organic mixes. I'm becoming a fan of organic mixes in containers as a result. Mostly because of a few commercial productions using organics. They didn't observe many of the problems associated with organics in pots. Some even have used pots for 7 years without changing soil. We are talking for commercial production here too. The plants and trees in these mixes were extremely impressive.
I grew mostly tropical's too, and the inorganic approach works well. In the last 5 years I have been growing edibles. But after seeing a 7 year old blueberry plant in organics yield 20 pounds of berries I realized that a living media for edibles was the way to go. Soil was never changed either btw, just more organics added every year. Seeing is believing. Not only blueberries but fruit trees, and grapes. Amazing yields all grown in pots. I was blown away. The grower used pots to fit more plants in his greenhouse. Outside conditions were not ideal to growing the cultivars he had. He had much better production inside, in pots, in organic soils.
I guess I had my intelligence insulted as I always thought this was not possible with organics. Boy was i wrong.

This year I'm growing 11 tomato plants. 4 are in ground, 2 are in 5-1-1, and 5 are in organic mixes. The 5 in the organic mixes are blowing away all others. Bigger, greener, more productive. Don't take my word, try it yourself.
One advantage to in ground is that it stays a lot moister than in pots. With ground cherries, I did the same thing. I let the one in an organic container get too dry. It killed the bacteria and such. So the in ground example is doing better. I usually add more bacteria to all pots about once a month. The bacteria are super cheap. Biota, and MycoGrow are used.
I also saw a set up for super hot peppers were the guy was getting hundreds of peppers per plant. One plant had 2 thousand peppers on it. So I'm totally sold on organics.

Are you referring to Sea Spring Seeds monster Naga pepper plant that grew 2,400+ peppers, Drew? If so, it should be noted that the plant was grown in a 42-gallon container - that's a mini raised bed, not a traditional backyard gardener container - and the plant was grown in a greenhouse (due to the weather in the UK). These details dramatically influence how well the heavier organic mix worked.

Josh

Thanks for clarifying, Josh... yes, I wouldn't exactly refer to 42 gallons of medium as just "a container". That IS much closer to a raised bed.

However, I will note that even in my own raised garden beds, I've added partially composted pine/wood mulch to aid in drainage and help with aeration. I'm not sure how many gallons of medium we're talking about... but the beds are approximately 8' x 8' square, maybe larger... and about 1 1/2' tall, and the bottom is open to the ground below.

I'm not as particular about the medium in the raised beds, because they only grow seasonal food plants... bush beans, zucchini, and other vegetables. I do refresh it every spring with composted goat and horse manure, more wood mulch, spent soil from smaller containers, etc...

But that's not a container. It's a raised bed. It's considered "garden", and because it's open to the ground, Mother Nature plays much more of a role in those beds than she ever could in an actual pot.

Different growers are, of course, free to use whatever concepts they feel work for them... but keep in mind that physics will always play a role. How water behaves in a given medium, and the purposes of medium, don't change.

Can anyone please guide me to a discussion of organic container mixes? I am using gritty mix and variations of 5-1-1 now, and would really like to use an organic media to compare and contrast.

Building healthy living soil mixes has always been my goal, but I just have much better luck in container growing utilizing inert media and synthetic nutrients.

Wow- never heard of such a thing in potted plants. In people yes. In plants, no. Thanks for the post.

In order to compare and contrast the two variants... organic and inorganic... I do believe it would be necessary to grow a plant type that remains viable for more than a single growing season.

In other words, growing a tomato or pepper plant, or a petunia wouldn't tell us very much because as soon as the growing season is over, the plants are done and go to the compost pile.

A true test would include a plant type like a perennial, or a houseplant... something that would remain in the same container for at least 2 years.

I think that might be enough time to prove out the theory that it's much more to our advantage to have the control over moisture, nutrition, decent aeration, etc... instead of allowing Mother Nature to try to cope within such a confined space, minus the balances she manages to keep in the vast space of a garden setting.