Morning frosts last longer now. Ice forms on mud puddles overnight and lasts all day. The gardening season has officially ended. Well, not entirely. Plant lovers can always feed their desire to cultivate some growing thing with the help of potted plants.

Indoor gardening is tricky, especially in winter. The main culprit is low humidity. For that reason our potted plants should never be placed near heaters or air vents, because these tend to draw moisture from plants. Other factors come into play too, including sunlight and water.

Regarding sunlight, we have two choices. First, a south-facing window has the benefit of direct, natural sunlight. But cloudy, dark days often see our plants begging for light until bright sunlight returns. The other choice is to use plant lights, special lamps that afford our plants the equivalent of real sunlight. Of the two, the windowsill is cheaper and easier to deal with.

Humidity, though, no matter where we situate our indoor plants, presents a totally different challenge. Dry winter air is a plant’s worst enemy. We have a few tools at our disposal, though, that can keep our plants happy and healthy during the dry months. First, it helps to keep plants in a humid environment. For most of us, that means near the kitchen sink. A sunny kitchen windowsill makes a good place to grow houseplants.

But when indoor humidity drops to dangerously low levels, we need to take extra precautions. One temporary fix is to place a clear plastic bag over our the potted plant. Moisture from the plant condenses on the inside of the plastic, creating a humid environment. This fix, while unsightly, can mean the difference between a desiccated, dried-up plant and one that continues to live despite arid surroundings.

If  I am going away for a few days, I always give my potted plants the plastic bag treatment. And it always works. As long as the plant has adequate water at the time of putting up in plastic, it will recycle that water and grow happily and fast.

Easy houseplants

Unless we specialize in some specific group of plants, African violets, for instance, most of us are happy with easy-to-grow potted plants. Luckily, there are lots of attractive plants out there to choose from. The following list, while not all-inclusive, includes lots of commonly available, user-friendly potted plants.

Cactus

With indoor humidity in winter being similar to that of a desert, it seems reasonable to select plants that can deal with desert-like conditions. One group of plants comes immediately to mind. cactuses.

Cactuses appear to thrive on neglect. Are you a bit lax when it comes to watering your plants? Then there’s a cactus out there for you. Cactuses can go for long periods without watering and still survive. Some good cactus varieties include pincushion cactus, old-man cactus, opuntia and urchin cactus. Slow-growing and enduring, cactuses are one tough group of plants.

Sansevierias

Common names for Sansevieria include snake plant and mother-in-law’s tongue. And if cactuses are tough, sansevierias are as tough or tougher. These hardy plants will grow in too-small plastic pots in dimly lit rooms. Or they will do just fine in direct sun on your kitchen windowsill. They are equally at home in a bank lobby or in the rest area of a shopping mall.

The worst thing you can do to a sansevieria is to overwater it. These plants can go months without water, but indoors during a Maine winter, watering should occur once each month. Feeding should take place every two or three months. This brings to mind an important consideration. Most plants benefit from regular applications of plant food. But growers' directions are designed so that we use more plant food than is really needed. So cut the suggested amount of plant food in half and your potted plants will thank you.

Asparagus fern

Hardy and resilient, asparagus ferns had their heyday in the 1970s. Then, nearly every kitchen window in America had an asparagus fern hanging in front of it. Every office had its obligatory asparagus fern, as did most restaurants.

Those days have passed, but asparagus ferns still work their magic in Maine homes. Like sansevieria, asparagus ferns can go for long periods without watering. They don’t necessarily like it, but they can survive.

Asparagus ferns belong in the lily family and are closely related to garden asparagus. Sometimes the plant even develops small, white flowers and tiny, red berries, the same as their namesake. These potted plants can go outside in summer and be brought back inside just before frost hits.

For the deepest shade of green for your asparagus fern’s foliage, situate it in partial shade. Plants in direct sunlight will exhibit a lighter shade of green.

Pencil cactus

Common names are so often misleading. Pencil cactus, Euphorbia tirucalli, is not a cactus, but rather is related to poinsettias and has similar milky sap. The common name refers to the thin, twiggy stems that may be said to resemble pencils.

This rather unique-looking potted plant thrives on dry soil, something all too common in Maine houses in winter. If not allowed to completely dry between waterings, the stems will rot. Also, pencil cactus performs best in full sun.

To my eye, pencil cactus bears a slight resemblance to one of my favorite seaside wildflowers, sea lavender. But others no doubt make lots of other comparisons. Interestingly, I never fully embraced the “pencil” connection. We all see things differently.

Pothos

The common name for this friendly plant, “devil’s ivy,” seems misplaced. Pothos prefers bright light and will accept medium light conditions. As a vining plant, it frequently shows up around windows and doors in restaurants.

Pothos is one of those plants that companies try to imitate with plastic versions. Indeed, my last visit to a local Oriental restaurant had me feeling the leaves on a pothos by my table to see if it was real or plastic. It was real.

I’m planning to set up a pothos as a hanging plant on the non-moving half of my front sliding-glass door. As it grows it will be easy to train the vines and their glossy leaves to follow the contours of the door frame.

Reasonable care will see to it that your pothos plant lives for many decades. It may, in a way, live forever if you take stem cuttings and pass them on to other gardeners, who will be expected to follow suit sometime in the distant future.

Hen-and-chicks

Hen-and-chicks, Sempervivum, is a perennial succulent, and another common name is live-forever. That speaks volumes about the plant’s hardiness. Often used in rock gardens, these drought-resistant plants grow with wild abandon. And in early winter, greenhouses offer smaller varieties for indoor growing.

As stated earlier, most potted plants will benefit from a light feeding every two months. Not so for hen-and-chicks. They thrive in poor soil and don’t need to be fed, ever. Do try to give them adequate sunlight, though.

And being succulents, hen-and-chicks needs water, but can persist a long time in moderately dry soil, making it the perfect potted plant for forgetful gardeners. Their succulent nature also allows them to thrive in shallow planters where water never lingers long. This allows indoor gardeners to get creative with container types.

Here’s an interesting note regarding hen-and-chicks' medicinal qualities. The sap can be used the same way as aloe vera for burns and abrasions.

Finally, while not flashy (the plant will sometimes sprout a flower stalk, but not always), hen-and-chicks ranks as a must-have plant for anyone, no matter their gardening ability or greeness of thumb. A must for growing inside during our dry Maine winters.

Geraniums

Most people trim their geraniums back in fall and place the plant in an attic to sit out the winter. But geraniums will bloom in winter, too, when given moderate care as a houseplant. It doesn’t hurt to trim your geranium back before bringing it inside. Just trim enough so that it isn’t spindly. Try to give a symmetrical shape if possible. After that, moderate light and occasional watering should keep your geranium going all winter. I don’t feed geraniums in winter, but for those who choose to, go light on the fertilizer and keep feeding to a minimum.

Tom’s tips

All plants need at least some water, but the worst thing you can do is to overwater. To prevent overwatering, absolutely do not water all your plants on a regular schedule, since they all have different water needs.

Instead, water “as needed.” Lift the pot to see if it is feather-light, in which case the plant can use some water. But always err on the side of caution. Water only as the plant demands it.