Where have all the flowers gone?

My garden is looking pretty colorless these days. The temperature is hovering around 44-45 degrees celsius and the heat is unbearable. And in case you are wondering, this was a rare day when it wasn't sunny because there was a dusty haze all over the city.
The only flowers blooming are the Portulacas on my balcony. And though the pots are too big for the planters, I decided I didn't mind them standing on them rather than in them.


And while we are on the subject of planters, these were made from wooden pallets, by a carpenter working at my home. And I quite like the way they have turned out though they have yet to be painted/polished. And that's because I'm basically not sure what to do! Any advice on the same, is welcome.