Wintering Herbs Indoors (part 2 of 2)

Yesterday I began a presentation on what to do when winter arrives and you want your plants inside with you.  Previously I discussed what to bring in, what not to bring in and how it is done.  Today I am continuing with making the plants comfortable and how to treat them while indoors.

Acclimatization

At this time of year there is still summery weather and frost is mild if at all, so rather than bring the plants in too soon, I leave them outside.  If a cold night is forecast, I bring them in over night, and then take them back out in the morning, much like I would to get greenhouse plants ready to be out in the spring.  This reverse hardening off, keeps the plants growing, but helps them realize there is change ahead.

As I said I move them closer and closer to the house as the weeks progress, sheltering them under trees or up against the siding so they can absorb the heat from the day into the night.  I also place them in shady areas away from direct sun so they becomes used to the lower light levels.  Once the days stay almost as cold as the nights, then they will stay in permanently.

 Cut Them Back

Once your plants are ready to move indoors, it helps to cut them back slightly (by as much as a quarter depending on the plant.)  Cutting them back stimulates new growth that will adjust to indoor conditions.  In many cases the older foliage will drop off when the plant comes inside.

Watch for insects

Whiteflies, spider mites and aphids are three main pests you can bring in with the plants.  You might want to go as far as examining your plants with a magnifying glass, checking for insects and eggs.  One of the last steps I take before moving a plant inside permanently is to give it a wash.  Using room temperature water, give them and overall gentle washing that includes tops and bottoms of leaves.  Mild dish soap can be used, but is not needed, the washing itself dislodges the little creatures rather well.

Caring for the Plants Indoors

I arranged the pots in the sunniest windows of my home.  In this case the picture window in the living room and the bedroom.  I like the scented geraniums in the bedroom.  There is nothing more intoxicating than being able to reach up a stroke the leaf of a scented geranium in the morning (relaxing too!)  They get leggy in winter so the ability to spread along my headboard seems to appeal to them.  Try to find a place with daytime temps near 70 degrees and evenings 55 to 60 degrees.

Humidity is required for indoor plants.  If you begin to see brown leaf tips or edges, this is usually a sign of low humidity levels.  To encourage enough humidity for your plants, sit them close together (they give off moisture) or set them on oversized trays of sand or pebbles.  Fill the tray with water so the bottom of the pot sits above the water line.  As the moisture evaporates it will fill the air around the plant with humidity.  Misting has been used to assist with this issue, but for perfect protection you would need to mist almost constantly.

As light levels diminish with the approach of winter, the herbs seem to enter a holding pattern. They generally don’t appear to be growing.  Water only when the soil becomes dry or nearly so. Sometimes I am lax with this, but the scented geraniums don’t mind.  Rosemary will, however require constant humidity, so if you bring one indoors, place it on a tray of pebbles and keep a level of water in the tray at all times.  This will protect it from the lack of humidity you have in a heated home in January and February.

Although the days begin to lengthen in late December, the herbs don’t seem to begin to grow until March. When I notice the new growth, I started fertilizing the plants occasionally with a dilute solution of soluble fertilizer.  Don’t fertilize them until then.

Keep a close eye out for pests.  They can lay dormant on the leaves of plants until reawakened by the heat and stress of the plant.  Dish soap diluted in water and sprayed on plants can cut down the numbers, as well was washing off the plants leaves, but depending on infestation you may need to segregate an infected plant.

Another issue that can affect indoor plants is mildew.  I have heard, but have not tried a mixture of baking soda and water used as a dip for stems can retard this once it starts.  However, good air circulation should keep it from happening at all.

Providing adequate light in winter is always a problem. Grow lights are a good idea, but even with them plants can become leggy, so do not expect too much.  I have used flood lights, fluorescent lights and even the new LED lights, but nothing can be a true substitute for sunlight.  I have stopped using them because I just trim the branches back in the spring and let them do what they want in the winter if it keeps them growing.

Putting Them Outside Again

At the end of April, I began hardening off the herbs I have wintered over indoors. I place the pots close to the east side of the house where they get morning sun but are out of the wind. Once the nights are mild you can leave them out all night.  This hardening off period can last a couple of weeks depending on the season.  But once the fear of frost is past you can then plant them outside again to enjoy another season.

Once the herbs are outside you can relax, -- or maybe not!

For more articles and recipes about the use of herbs, check out our Facebook page and websites through http://www.backyardpatch.com/

Wintering Herbs Indoors (part 1 of 2)

Finally our first frost has come.  Not a tough one and most plants were unaffected, but that automatically changes my focus from brining in the harvest to bringing in the plants.  I know that some herb gardeners live where winters are frost-free may be able to get away with doing what my body wants right now which is to relax and wait until the seed catalogs come in January so I can plan for a new year.  However in Illinois, in Zone 5, I have to recognize that some of the plants I love cannot possibly stay outside all winter and return in spring after a nap.  Plants like rosemary, tender lavenders, flavored thyme plants, or other plants that will die if the temperature goes below 15°F must be handled in some way and now is the time.

For me I like to have some plants indoors for winter.  The scents and the ability to cook with them in winter are important to me, so over the years I have devised a plan for saving the plants from winter’s chill.

What Not to Bring In

Perhaps you love all the herbs in your garden equally, and you’d like to bring them all indoors. I suggest you don’t, even if you have a huge house with dozens of south-facing windows.

First of all, forget about the annuals, such as summer savory, chervil, cilantro, borage, and dill. Their lives are about over; if you want them indoors in winter, you can start new plants from seed.

Don’t bother bringing in tough perennial culinary herbs whose dried leaves have good flavor—I’m thinking of sage, oregano, and thyme—unless you think you can’t get along without the fresh leaves. Consider the size of the plants, too, and how many smaller plants you could put in their place in front of the window.  I grow lemon thyme in a window box along with a small bunch of chives and that window box always comes back inside in the fall, so I can snip fresh thyme and chives.

Don’t bring in huge tender plants if you don’t have room for them, no matter how badly you need them for next year’s herb garden.

And if space is limited, abandon tender perennials that are easy to start from seed. Marjoram is a good example—unless you ­absolutely must have it for midwinter salads.

Lastly, turn your back on plants that are diseased or pest-ridden. Even plants that are healthy now can become afflicted in the harsh atmosphere of the indoor desert, but there’s no sense in helping disease and pests get off to a good start.

What to Bring In

Several plants are worth bringing indoors. I suggest you keep tender perennials on which you’ve lavished special care and affection. These include unusual cultivars; plants of sentimental value for me that is my lemon verbena; expensive plants such as bay laurel; and herbs that you intend to propagate next spring (such as scented geraniums). And bring in plants that will look great as house plants, such as that prostrate rosemary in the hanging basket.

What about that absolutely wonderful tender perennial pineapple sage or pineapple mint that smells so good? Chances are they are too large for any window you have and may be too big for any pot you have, the solution is to take cuttings right now.  Using a rooting compound, take slips near leaf nodules, dip them in rooting compound and place them in water or moist sand. They’ll root in a couple of weeks and will occupy only a modest space by the window thereafter. If the new plants show signs of taking over the windowsill, take cuttings from them, and so forth, until it’s time to set them outside in the spring, after the danger of frost is past. If you’re not sure about the hardiness of a large perennial plant, you can take cuttings now and winter them indoors in case the original plant doesn’t survive.  I’ve done this with some of my favorite thyme plants because in Illinois, you never know if winter will cooperate and leave a protective blanket of snow in January or not.

What I Brought In

In September, a couple of weeks before our anticipated first frost, I looked over my herb garden, then looked over my sunniest windows, and tried to predict my craving for fresh herbs in the depths of winter. The herbs I decided I had to bring in included five tender perennials: a prostrate rosemary (Rosmarinus officinalis) I was training into a pine tree shape.  My two scented lemon & lemon rose geraniums (Pelargonium crispum ’), W small savory plant I got as a gift, and a lemon variegated thyme.  This year I did not bring in the Pineapple sage, even as a clipping because the plant was so effected by the heat this year, that it just did not seem healthy enough to give me good cuttings.  Oh well!

 How I Did It

All the herbs I planned to bring indoors had spent the summer in the ground. The healthy top growth hinted that the roots had also grown significantly, and so it turned out. I’m always surprised to discover how big the root mass gets when it’s not restricted by a pot.

I mixed up a potting medium that includes course sand and organic matter for nutrients and draining.  When I transplant I try to keep the soil with the roots, just knocking off the excess.  This cuts down on the shock to the plant.  That means I just need the new soil to fill in the bottom and the top of the pat as I am transplanting.  I keep some on hand incase the soil sinks in the winter.  If you don’t like the weight of sand you can substitute vermiculite or perlite.  I use a blend that is 1 part potting soil, two parts peat moss (organic matter) and one part course sand (be sure not to use play sand, that is like clay.)  Dampen the mixture so it does not leach the water out of the existing soil.

You can dig the plants up with a shovel or trowel, but using a trowel requires strong wrists.  This year, following my hand injury, I don’t have the strength back yet, so I used a shovel.  I found it to be much easier and may switch to this from now on.

Choose pots that are slightly larger than the root mass of each herb. I have a wide variety I have collected and saved over the years, but any pot will do, if you want a uniform look you can choose all terra cotta or you can wrap them in aluminum foil like I did one year.  It looked sparkly from outside!  If you have used the pots this year, be sure to wash and bleach them before reusing.  After laying in the plants, I watered them thoroughly and moved the pots into the shade.  I move them closer and closer to the house as it gets colder, bringing them in overnight if frost is predicted, but setting them back out during the day.

TOMORROW

I will finish up this post tomorrow with details on the final prep before brining them in permanently and how to care for the plants while indoors.  Please stop back!

And for more articles and recipes about the use of herbs, check out our Facebook page and websites through http://www.backyardpatch.com/

by Marcy Lautanen-Raleigh