Wont help much. Suggest that they sit inside the window sill instead, where indoor temps are a bit milder. Very large real clay pots cna help a little, but they do need lots of water too.

You can do a combination of things:

1- preferably use plastic pots. Clay will loose water much faster.

2- preferably, use bigger pots. Smaller pots dry up quicker.(less resrvoire of water)

3- Use a water tray under the pots and keep them full.

4- The poting medium has to have peat moss , pearlit, compost and some clay to retain moisture. Avoid sand and sandy soil.

5-use light color pots. Avoid black and gray. White(egg shell) is the best.
6- Wrapping the pots with aluminum foil can reflect the direct sunshine heat and reduce temperature built up.
With an egg shell white color pot probably wou won't need to do that.

The final note: Water the plants, very early in the morning or several hours after sunset whem it has cooled off. Never in the middle of the day, unless it is an emergency.

by doing these and when the plants shade over the top, less moisture will scape/ evaporate

How about trying those crystals that keep soil moist. I've used them and they work great! You can work them into your pots, water and they will swell to keep the soil moist.

Carrie

Great advice everyone, thanks.

But what I'm most worried about is the actual heat. The soil will roast in that sun and especially if it has a lot of water in it, it will steam. I think water could potentially only worsen the situation after it has time to heat up (and hold all that heat). It would definitely be best to bring it inside or shade the pot.

I was using the aluminum foil as a way to shade the pot..
But am afraid it could insulate it too

You could also try double-potting -- put the planted pot inside a larger plastic pot, leaving a space between the two to insulate from the sun. But if the sun is directly overhead, it sounds like your plants will need a parasol!

What about erecting some sort of shade to cover them in the really hot prt of the day/? Even a open umbrella will cool it a tad....-cass

I don't know how large these herbs are - but if they are not that big - the Dollar store sells baskets of all sizes with holes on the sides (and obviously the bottom no holes)...I use them to cover new seedlings in the garden - to keep the hot sun from scorching them and to keep rabbits from eating the new greens.

The holes vent the plants and lets in enough light -

Carrie

Shading is the best idea. There are lots of shade materials out there...like a dog kennel shade, has grommets, you could attach it to the fire escape with zip ties.

this is crazy...freeze bottles of water and put them in the pots...prick them with a pin so that the water drains out slowly as the ice melts. you would not want the frozen bottle to touch the plant material and damage it though...or use cubes of ice.

Double potting sounds like a great idea, if cost is not an issue.
If there is some room between the two, put some heat insulation, home insulation type or fill with pearlite/popcorn stuff. This should minimize radiative heat penetrating into the pot a great deal.

I like your idea, jmpete - :0)

Carrie

If we read the original post, you'll see that rashomon is not allowed to put up anything that will provide shade on the FIRE ESCAPE (this is not a patio or porch).

Double potting is truly the best bet. You could even use something like vermiculite or bubble wrap as an insulator between the two pots.

If you water thoroughly in the evening or early morning, your plants will have the time to take as much water as possible into their little plant bodies before the heat of the day commences. If the containers are relatively small, you may need to water twice a day. Watering is a beneficial practice for plants...not only does it provide the required H2O, but flushes the soil with a new supply of fresh oxygen.

I respectfully disagree that you should keep a full water tray under your plants at all times. If you do anything to create a water-logged situation, then roots begin to die right away. Then your plant is really in trouble. Plant trays should be emptied a short time after they fill up following a good drenching.

Hopefully, you are using a soil-less potting mix (peat based) and is porous and well-drained. Avoid adding sand, clay, compost, or anything like that to a container as those ingredients clog up the small pores in the soil system that ought to be filled with water and air.

The level of water in tray is not going to be that high to cause root rotting. That is why a built-in tray is incorporated to most hanging baskets. With a soil-less medium, as the water is depleted (by evaporation from top) the water in the tray is sucked in. This may help prevent drying out too fast.