What to do with rosemary to keep it from drying out?
Since rosemary is not winter hardy in the midwest, we bring them in every year. We get the same results every year. It holds steady for a few months. Then, no matter how much I water, it starts to flower, and then dries out within a week and dies.
We LOVE rosemary and use it all the time, but can't seem to keep it thriving.
We live in Ontario and I've figured out (I hope) a way to keep my rosemary alive all winter, after losing quite a few plants over the years. First, I keep it potted all year round - even outside. A nice roomy pot that allows it to grow. When frost threatens, I bring it into a bright but cool place where it spends the winter. Kitchen temperatures would be deadly - my rosemary plants spend the winter in my husband's workshop which is heated but not comfortably. They live right in front of a south-facing window which is bright but, let's face it, in the northern winter the sun is pretty anemic. Keep it watered regularly and don't worry about trimming off any leggy growth until it goes outside in the spring. At the first sign of warm weather, start letting it stay outside - first just during the day, and then eventually you can let it stay out overnight (unless expecting a very hard frost). When it goes outside for good - in this area it's probably late April - I give it a shot of fertilizer and trim off the leggy stuff. New growth will be heartier. Feed it once in a while all summer and repeat the cycle. Works for me.
A friend never has trouble with rosemary. She puts a humidifier next to it all winter. I think some varieties are hardier than others. I had one that did ok in a pot on the back of the toilet in a north window of a very small bathroom. The shower probably helped with the humidity in the room. I ended up giving it to someone else after two winters.
A friend used to leave her rosemary all alone during the week sitting on her deck on the Maine coast. She had it in a terra cotta pot and would fill the saucer with water when she left each sunday night. Frankly, I almost didn't believe her. Maybe some neighbor was sneaking over to give it more water during the week.
Some helpful info from Growing Herbs Indoors:
A plant that is adapted to abundant light often turns brown and drops leaves indoors. This is because it can't produce enough food to maintain itself. The plant tries to make food by shedding the inefficient leaves and producing efficient leaves higher up and closer to the light source. When you bring herbs indoors, this leaf drop and increased leggy growth can happen within weeks, or even days. Some herbs cannot make the transition fast enough to survive.
Rosemary is a case in point. This slow-growing evergreen doesn't have the chance to adjust to changes in light before the plant slowly starves itself. By January, February, or March, the leaves dry up, and the plant dies. This sudden death is by far the most common complaint about growing rosemary indoors. Here's what to do: Gradually adjust the plant to lower light. Place it in partial shade for two to three weeks, then in deeper shade for another two to three weeks before bringing it indoors. When plenty of new growth appears, the plant is ready to go into the house.
My Mom used to bring her rosemary plants inside and place them in the sunniest window. She would have a spray bottle handy and spritz it about 5-8 times a day. She had pretty good luck with it. When she went away for a few days she would put a large, clear plastic bag loosely over the plant and fill the tray under the pot with water.
To me, it sounds like the air is too dry. Do you have a window in the bathroom so it would get light but get the steam also? Is your ground usually under snow alot of the winter? If not, you might be surprised how hardy rosemary is when in the ground. When we lived in Oregon, we rarely got snow but had subfreezing temps alot. The rosemary grew like a weed. I had to use loppers to control it.