Oklahoma Cooperative Extension Service, Division of Agricultural Sciences and Natural Resources
David Hillock, Consumer Horticulturist
With cooler temperatures of fall and winter fast approaching our gardening interest often turns from plants outside to plants indoors. Success with houseplants is governed by one’s careful management of light, temperature, water, nutrients, and humidity, along with using the proper potting medium.
Light – Very few plants tolerate dark corners. Most houseplants require the light that would be found within four to eight feet of a bright south window. Some will tolerate a spot very near the window, while others will prefer less light some distance away. Too little light can result in tall, lanky, small-leafed plants. Too much light can cause leafburn on sensitive species like African violet. If the room is not naturally lit, artificial lights should be used.
Temperature – Most houseplants prosper in a temperature of 65°F to 75°F, but the humidity of the average home is too low to suit them. A plant prospers in relative humidity of about 50 to 60 percent, which is more than most people like. This can be helped by using a humidifier or by setting the pot on a tray of moist gravel or pebbles. Do not allow the water to touch the bottom of the pot, as the water would then be wicked into the potting medium and keep the plant too wet.
Watering – More houseplants succumb to improper watering than from any other single cause. In general, most houseplants need to be thoroughly watered and then allowed to nearly dry before the next irrigation. Use tepid water when watering houseplants. Enough water needs to be poured over the potting medium to allow water to drain freely through the drain hole at every watering. If water does not drain out the bottom, rewater until it drains freely. Never leave a houseplant standing in water, as this will cause the roots to rot.
Drainage – Drainage is an integral part of watering a plant. Do not include aggregates in the bottom since the aggregate actually slows water’s movement through a pot. If a decorative, drainless pot is desired, it would be better to use a “pot within a pot” technique: pot the plant in a container with drain holes and then set that into the larger, decorative pot. Never allow excess water to collect in the outer pot.
Potting Medium – Consult your local garden center, greenhouse or florist for help selecting an appropriate potting medium. It is important that the potting medium has good water holding capacity yet is loose enough to promote good drainage and aeration.
Fertilizers – The easiest way to fertilize your houseplants is while watering. Select a houseplant fertilizer and dilute according to label directions. Houseplants can be fertilized at every watering with a very dilute rate or fertilized at a slightly higher rate once every third or fourth watering. Do not fertilize as often or as much in the winter, in dimly lit rooms or in potting mixes that contain soil.
For more information about growing and maintaining houseplants see OSU Extension Fact Sheet HLA-6411 – Houseplant Care.
We have been busy planting bulbs in the gardens, but we do not have to wait until spring to enjoy these blossoms. Many spring-flowering bulbs can be forced indoors for a colorful winter display. What better way to brighten up a winter day than with fresh flowers?
“Forcing” is the term used to describe the process that stimulates bulbs to bloom out of season. The easiest bulbs to force are Paperwhite Narcissus because they don’t require chilling. Other commonly forced bulbs include amaryllis, muscari and hyacinths. More challenging bulbs for forcing include colchicum and miniature iris. When selecting bulbs for forcing look for varieties that are specifically recommended for this purpose. Most bulbs require a chilling period or period of cold temperatures before they will bloom, but bulbs sold specifically for indoor forcing are pre-chilled, removing this step for the gardener.
Paperwhites are quick and easy to start and will bloom within four to six weeks. Start by selecting a container without any drainage holes. A clear glass vase can be used so you can see the roots of the bulbs growing, but many different types of containers can be used, if it is deep enough to hold about 3 inches of media.
When forcing bulbs, it is not necessary to use soil as the medium, though you may. It may be easier to use washed pea gravel or glass pebbles that can be purchased at craft stores. The stones or gravel will hold the bulbs in place as they grow. Fill the container with about 2 inches of growing medium. Then, place the paperwhite or other bulbs on top of the pebbles. For a nice display, set 7 or more bulbs close together so they almost touch. A large bunch of bulbs will be more dramatic. Set the bulbs so they are perfectly upright. Wiggle the bulbs down into the pebbles a little bit and then fill in around the bulbs with more pebbles. You do not want to completely bury the bulbs, instead, leave 1/2 to 1/3 of the bulb exposed.
Once you have the bulbs in place, add just enough water to the container to reach the base of the bulbs, but not touch the bulbs. Do not let the bulbs sit in water or they may rot. One of the reasons to use a glass container is that it is easy to see the level of the water. If you are using a solid container, just dig a small hole next to a bulb so you can see the water depth.
To start the rooting process, place your container in a cool room that gets low light or no light, such as a windowless room. Keep your container at low light levels until the roots begin to grow well and the shoots start showing – usually about 1-2 weeks. Keep an eye on the water level and refill as necessary to keep the level just below the bottom of the bulbs.
Once you have good root growth, move your bulbs into a warmer bright, sunny window and watch them grow! Once the bulbs begin to flower, move them out of direct sun so your blooms will last longer. Your home will be filled with beautiful flowers and the refreshing aroma of spring in the middle of winter. Plant batch after batch to keep flowers blooming all winter long. Paperwhite containers make beautiful centerpieces for the table during the holidays and are also great to give as holiday bouquets. Or force paperwhites with your children to create unique gifts for their teachers or grandparents.