before I knew that should paint my black containers white I planted and now I don't know what do about the containers getting to hot. Would wrapping them in tin foil reflect enough heat to make it cooler or can I just paint it now, also the pot I am talking about is an accelertor pot and has holes in it for the air pruning effect so some of the soil is visible.

Not the answer but what I'm doing this year is:
My pots are doubled - every pot is in a slightly bigger one.
One, for which I have not suitable 2nd pot, wears a skirt.
2nd pot should serve for termoisolation and also:
gives better stability in case of windy condition - additionaly, gap can be filled with sand...
makes more problems to ants climbing...

When temp go high (~ 28 C and higher) I move pots with smaller plants on some place where the top of the pot (top soil) is in partial or full shade during the hottest part of day.

BTW: I'm curious which light is better for new growth to come, morning or evening?

maybe you could cover the holes and paint?? I forgot to paint my pots till my trees were in.. I did not have the problem of the extra holes.. but was worried over spray would harm trees.. So I used lawn and leaf trash bags to protect the tree while I sprayed the pot..
I'd use tape or stuff wadded up paper in the holes to cover them and protect the roots and dirt while you spray the pot..
Some only paint one side so on cold days the black side of the pot can be turned towards the sun to help warm the pot.. and the lighter side turned on hotter days..
Just my 2c.
Good luck hope this helps..
Gina *BabyBlue*

Thanks would making a slip cover out of white frabric do and then on cold days I could take the slip cover off. For painting it i could just use a paint brush and brush in one instead of spray paint to.
.

I have painted accelerator pots and root builder containers many times while trees were already growing in them with no trouble what so ever. I generally use the common aerosol spray cans. If you cover the container you can lose the benefit of the air root pruning. - Millet

I would worry about soil washing out of the pot and into the slip cover and collecting there..
I've noticed with my air pruning pots that soil washes out easy.. If the slip cover collected the soil it would negate the effect of the air pruner..

I lightly water my plants in the root pruners.. but if there were a heavy down pour of rain. it might cause problems..

But then.. maybe if you made it open on the bottom and put in a slight elastic at the top to hold it up??? so soil could pass on through if it washed out some and wouldn't collect in the bottom of your slip cover..

Interesting idea...
though slip covers might be more trouble than they are worth... guess it is up to you how much work you want to put in to it..

Gina *BabyBlue*

would a green pot be any better?

Thanks guys I will just paint it anyway, but today i am going to use something temporary because we are getting up to 27C (80F) and yesterday my plants cooked (to early for such hot weather) so i have to protect them.

Nospice-- green would be only slightly cooler than black. Black absorbs all colors of light, green all colors exept green-- white reflects all colors.

I have "planted" most of my seedling pots. I have had a couple try to put roots into the ground, but I just put a piece of root control fabric under the pot when that happens.

Gina, the type of air root pruning container Valencia is talking about (Accelerator) is different than the type you thinking of. I don't think soil would wash out from his container. - Millet

I found this table on reflectance...it may confirm what some of you already do.

Quote:

The following table will illustrate the reflective value of the various materials available to the home gardener: Reflective Chart Material Reflectivity Black Less than 10% Aluminium Foil 55-70% Semi-gloss White Paint 60-70% White / Black / White Film 70-85% Flat White Paint 75-80% Polystyrene Foam Sheeting 75-85% Mylar Sheeting 90-92%

Ref: http://www.1-hydroponics.co.uk/web/manual/light/index.html

Two interesting things to me here. The first is the extent to which aluminum, with normally >92% reflectance, becomes inefficient as foil because of wrinkling or damage. The second is that flat white paint has greater reflectance than semi-gloss.

SB