You can keep poinsettias from year to year, but it might be easier to compost them

The end of December is the start of the New Year, and if you want to make 2020 the year you keep your indoor and outdoor plants healthy, here are some tips and answers to your growing concerns:

Q. I purchased a dozen poinsettia plants to line the stairway in our home. The display was lovely but now that the holiday season is ending, what is the best way to keep these plants alive to use next year? — J. via email

A. Potted poinsettias can be kept alive if grown in bright light (an Eastern exposure is ideal), kept watered when the soil feels dry to the touch and then properly pinched or pruned in early summer to encourage branching. But there are a lot more steps to take if you want those potted poinsettias to bloom again next year.

They can enjoy the summer outdoors in light shade, but once October arrives you will need a big, dark closet. So here is the tricky part — it is the short day length that forces the leaf bracts to turn color and any bit of light during the night will upset this coloring process and leave you with nothing but green foliage for Christmas.

You must remember to put your poinsettia into a dark closet every night for the months of October and November. Be sure you bring the plants out into sunlight during the day.

Because poinsettias are short-day plants, they need total darkness from 5 p.m. to 8 a.m. every single night. All this covering up or moving a dozen plants at night is a lot of work.

You must also make sure the plants get enough humidity, fertilizer and water. Perhaps the best thing that could happen is for you to forget to water. Then all your poinsettia plants will drop leaves and turn yellow this week. Then you won’t feel so bad about dumping them all into the compost pile and starting with fresh plants again next year.

Q. I was given an orchid for the holidays, and I really want to keep it alive. The instructions say to place an ice cube once a week on top of the soil. My neighbor says this is nonsense and I should just feel the soil and water when dry. The orchid is not in soil, it is growing in bark chunks. What do you say, ice cube once a week or listen to my neighbor? — J.M., Tacoma

A. Score one for the neighbor. The local orchid growers that I talked to insist that the ice cube treatment is risky as watering needs change depending on humidity and sunlight.

Also, you most likely have a phalaenopsis orchid, and this warm season bloomer hates ice-cold water. Your orchid needs to dry out completely then soaked with water.

Do this instead: poke your finger into the bark and feel down a few inches. Water only when the bark is completely dry — better to under-water than over-water.

The ice cube method came up because it was a simple way to keep people from over-watering their orchid plants.

To soak the roots of your potted orchid let the pot sit inside a bowl of water for 10 to 30 minutes. Do this only when the bark is very dry — usually once every 7 to 10 days, but it could be once a month.

Orchids need very little fertilizer, so only use a slow-release plant food once a year or so. There is no need to buy special orchid food.

The secret to orchid-growing success in Western Washington is not to over-water. Our wet winter days mean high humidity and low light so plants need less water in the winter. Just feel that soil before you think about watering. Better yet, wait three days after you think the soil is dry. Once you get the hang of how lightweight the pot feels when the bark is totally dry, you will have an easier time just lifting the pot and knowing it is time to set it back down into a bowl of tepid, not freezing, water.

Q. We were given a living Christmas tree of clipped rosemary. The plant has been clipped into a cone shape, but now I think it needs more pruning as it is growing bushy. My question: Can I plant this potted rosemary plant outdoors? — T.J., Kent

A. Yes, rosemary is a Mediterranean herb plant that can survive cold weather, but it cannot survive poor drainage, heavy snow or winter temps below 0 degrees.

If you have a protected spot in the sun with perfect drainage, and, if you promise not to over-water, your rosemary plant can live for years outdoors in Western Washington.

Before transplanting your potted plant into the ground let it sit outdoors on a covered porch or patio for a few weeks until it gets used to colder weather. Move the potted plant indoors if a freeze is expected.

Rosemary loves sandy soil and does not need fertilizer. Prune the fragrant foliage by a few inches any time of year to keep the tidy cone shape or allow the plant to grow into a taller shrub.

Fresh rosemary sprigs are great for adding to stews, soups and meats. They also can be used to make a pungent tea or to perfume bath water.

This story was originally published December 21, 2019 at 10:00 AM.