Cilantro leaves are only good until the plant bolts (grows a flower stalk) in hot weather. Then the leaves change shape and lose their flavor. At that point, you can consider it dead or wait to collect the seeds which can be ground as a spice. (aka: coriander).
Lucky... I found out about...
The main thing I do with lemon balm is tea. I commonly add a few crushed leaves when I brew green tea for the flavor. The leaves can be added to a mixed salad and used as a flavoring in other foods.
Mints are good medicinals. Lemon balm in particular is good for reducing stress & insomnia...
Quite a collection you have going there. I have a fair number, but have a small property and garden so I've had to be more selective.
A dehydrator will indeed make a room or so smell like whatever you are drying. It is basically warm/hot air (90-140 degrees) blowing over your product. My...
Most herbs are too thin to really need a dehydrator as they can pretty quickly air dry. Dehydrators are really better for larger/thicker items that would take forever to air dry- vegetables, jerky, etc.
Basil is a short-lived perennial or biennial (2yr) plant, so it can be overwintered indoors. 69° is a very reasonable temperature, so I'd suspect other issues like lack of sunlight or possibly pests if you brought it from outside. You could keep it alive through the winter and have it grow...
Ahhh... Chickens deprived of greens can will eat almost anything. Be careful with that. They can be induced to eat something not healthy for them in those conditions.
Don't know why, but that is very individual. I have mints and comfrey and my girls ignore them. They do free range, so there are plenty of other options.
Are you bringing them in from the outside? That will generally bring in gnats.
If you've eliminated gnats and then start them in "potting soil" (which is sterile), then you shouldn't have a problem.
Many mints are good for herbal teas or to flavor ice-water. I've often brewed green tea with a sprig of some type of mint (peppermint, spearmint, lemon balm) to vary the flavor. Also, many have medicinal value. Just search for "<mint-name> medicinal" or "<mint-name> herbal" to find out where...
Generally leaves are easily air dried. They will dry as quickly (12-48 hrs) as thicker things in a dehydrator. Just do the best you can to keep them away from dust for that period. If you are concerned about dust, I'd store them in mason jars or crush them and put in spice jars longer term.
No need to reseed. Just clone any existing mints. They are very easy to propagate. I think the problem is that they become root-bound in the container. Just clone the old mint and let them grow inside during the winter.
The parent mint will be hard to kill, but I did it via dehydration...