Round pot mystery....

[Deb P]

I potted on my chilli and pepper plants ten days ago, and yesterday was organising them on my greenhouse bench, putting the largest at the back. I then noticed that the largest plants were all growing in round pots; I had used a random mixture of round and square pots, same height and soil capacity, the same phenomenon seemed to be applicable; what is going on?

[oldherbaceous]

Deb P, just wondered are the round pots the same colour as the square pots?
Something strage is going on.

Kind regards Old Herbaceous.

Theres no fool like an old fool.

[Deb P]

The round pots are terraotta coloured, the square pots are black; do you think that would affect the heat absorbtion? Perhaps the square pots are heating up more and affecting the roots? Everything else, soil, watering etc has been the same, but the difference in height is quite marked, about 3" taller in the round pots, both the same bushyness (if that's a word!)

[David]

Dont worry I've ordered up the men in white coats the'll be round in a minute - in the meantime stay off the parsnip wine................

D

[oldherbaceous]

David, thats the sort of comment i normally come out with.
Deb P, i really don't know about this, i'm wondering if it could be the soil temperature making a difference. You will have to try it again some time just out of interest..
I think bushyness is a lovely word.

Kind regards Old Herbaceous.

Theres no fool like an old fool.

[Garlic_Guy]

Interesting one Deb!

A minor point, but in sunlight, something black would absorb heat more quickly than a lighter colour. However given the heat of the last few days, the air temperature might have got both quite warm.

I suppose the other obvious factors bewteen the two might be differences in:
- The overall volume of soil
- The drainage in the bottom

It would be really good if someone could repeat this experiment, to see if it was just chance. You might laugh, but I'm sure I read that a brewery decided to replace their original spherical brewing vessels with rectangular ones. However after several batches of noticeably different beer, they changed back to the originals and all was fine again.

Now, I think it's time for a glass of David's Parsnip wine........

[Carole B.]

I potted my peppers in round terracotta pots except for the last three which went in round black plastic ones and those three are noticably greener and bigger....could be something in the warmth theory.

[Deb P]

I feel an experiment coming on.....!

[peter]

Rusty on the maths, BUT :

Does a cylinder have a lower ratio of surface area to volume than an oblong cube?

A curved surface presented to the effects of the sun will absorb less radiant energy than a flat surface.

Both the above could give a significant temperature and water loss difference between the two types of pot.
The colour will also make a difference, black will both heat up and cool down quicker.
Finally the material the pot is made of will also alter the growing conditions, a terracotta pot will "transpire" where a plastic one will be impervious.

OK, thats the dictionary dealt with, someone do the experiment.

[Chez]

We've found exactly the same. Plants seem to do better in the round terracotta-coloured pots, than the square black ones.

I was responsible for the purchase of the square ones, as they fit better when stacked in trays, etc. OH has always maintained they are not as good. When he was a commercial grower, he only ever used round pots. In agreement with your maths Peter, he also prefers round pots as they allow more air to circulate between the plants when the pots are grouped together. He has commented in the past, that that roots grow in a round shape so round pots were better for that reason. He readily accepts that none of his thoughts have any scientific foundation by the way. But he still won't use the square pots for 'his' plants.