The wet, cooler weather of these last few days has prompted many folks to bring their summer patio tropicals back inside. Actually, late August is the best time to recall your houseplants vacationing outside. The climatic change is not too abrupt at that time, and they will adapt more quickly to inside conditions. Half-hardy plants like fuchsias, geraniums and lantanas do not like normal household conditions and since they will tolerate light frosts, leave them outside just as long as you can, probably until the end of October.
Several major problems arise, however, when tropical houseplants come back inside. Unwanted visitors often come back in with them. Many insects lay eggs on plants, and these eggs will hatch indoors and begin causing problems almost immediately. It would be wise to spray most of your plants with organic ‘Safer’s Insecticidal Soap’ or with the more broad spectrum ‘Trounce’. Spray three times five to seven days apart. For scale and other more challenging insects, horticultural oil, used at the growing season ratio, is also very effective. If you’re not sure if the oil will affect some plants, the rule is to spray a few leaves and wait 24 hours to see if any burning takes place. We have had great success with organic oils on all kinds of plants with little or no problems. Be sure to use the growing season ratio.
It is more difficult for plants to adapt to a household climate, rather than to an outdoor environment. You really must create a somewhat humid condition around all these plants until they can tolerate the less humid indoor air. This is easily done by placing three to four long bamboo canes in the pot and draping clear poly over top of create a mini-hothouse. If you mist the foliage with warm water two to three times daily, you will be able to remove this tent in about seven to ten days. This may seem like a lot of work and can look a little tacky, but it will make a tremendous difference in the quality of your plants. The secret to good maintenance on all plants during winter is plenty of light, lower room temperatures and proper watering. All plants will need higher light intensity during the short, often cloudy, winter days, so place them near indirect light, such as near windows on the north or east side of your home. Not only is it more economical to run your house temperatures lower, it is also more beneficial to your plants. Most tropicals will tolerate a low of 55˚F (10°C) but 62-65˚F (16-18°C) is most preferable during winter. If your furnace comes on less frequently, the air will be more humid. If you can, leave the summer fan running on your furnace for better air circulation. When you water all your indoor plants, water them thoroughly with warm water. The secret is to allow the soil to become dry before you water again. By picking up your plants and feeling their weight, you will instinctively know if they need water. Also, plants love to be root bound, so don’t repot them in large pots with volumes of soil. Try this approach on your indoor plants, and I’m sure you will notice a tremendous difference.
As far as other outdoor plants are concerned, leave them outside as long as you possibly can. Slips and cuttings can be taken now, but ‘mother plants’, especially those near the house, can often stay out until the first real cold spell. You can protect them from heavy frosts with protective coverings like the new insulating clothes now available.