A hot bath makes your Dahlias crisp, vibrant, and increases the longevity of the bloom. Heat water until it reaches between 160 and 170 degrees. Add floral food/preservative to the water (optional). Pour water into plastic buckets about 2 inches deep. Avoid using glass containers as the water seems to cool too quickly. Place Dahlia stems in water buckets until the water cools (usually 1 to 2 hrs.). I sometimes leave mine in overnight. It won’t hurt them.
You may, at times, experience that blooms freshly cut may start to wilt a little (before getting them in a cooler location). If they have a slight wilt/droop, a hot bath will usually perk them back up to their original fresh cut beauty.
It is best to cut your stems at about a 45 degree angle. This makes more surface area for your water to absorb into the stem. Warm stems absorb water more quickly and easily while the top bloom stays cool. Make sure you cut the stems long enough to place at a side angle or high center in your hot bath container. This is so that the steam can easily rise away from your flower so it doesn’t damage your petals. If you do find wilted petal damage, you can always choose to carefully pluck off the petal. The part of the stem that was in the water will turn a dark color. That is normal. The hot bath is only given once after the first initial cutting.
I use Floralife Crystal Clear 300 food/preservative. You may want to look around to find what works best for you. I like this brand because it leaves the water clear rather than having a bit of a milky look to it. This works well for clear glass vases.