Yes, it must be the temperature. It is the first time I've tried planting wallflowers when they should be planted....!
But, also in relation to the heat, I put a fan on the shelf with two of my best tomato plants,to try and keep them a little cooler. I think the vibration took them to the edge - a big crash and two-thirds of my green tomatoes came off with the plants on to the floor. Boohoo.
Now I am trying to ripen them on a windowsill.
Another assassination attempt on Donald Trump
The main room in your house...
