Out weather is finally starting to warm up to 60's for highs and 40's for lows. Does the ground need to be a certain temperature before I can plant my Gladiolus bulbs and Dahlia tubers? I also have Glads growing in pots. Will nighttime lows in the 40's hurt the plants if I plant them out in the ground now? Here is a picture of them in my garage. The two outside pots are Calla Lily.

Hmmm... I honestly do not know - I have mine in pots and will not plant them out for at least another couple of weeks and I'm in a slightly warmer zone than you. I do not think they would die if you planted them out now, but they might suffer a setback - the question is how serious?

Have you been putting them outside in a protected spot to harden them off? Because that is definitely a good idea before planting them out.

Hope someone else will know more!

Thanks Lilli. I guess I will wait another week or so. I will be sure to harden them off before planting them out.

Gladiolus bulbs should be safe as they take some time to emerge. I've sometimes heard that the soil temperature should be around 50F for dahlias. In reality it also depends on how your soil is. In lighter soil you can plant them out whenever you can manage to keep them frost free. The risk is of course rot and I would be very careful with water before the plants start to grow.