Posted: 20/03/2015 at 18:52
For hardy perennials you can leave the vents open now, and the door. My doors haven't been shut for weeks. I only close down for gales and the vents sort themselves out. As you know Fishy, my gardening style is not as precise as some but the plants grow. I water in the morning while the night are still coldish.
Another thing to consider for later is shading, it reduces the stress.