Most of us look forward to a little more living space in summer. The houseplants go to the porch, patio or deck. Some folks don’t do that because of bad past experiences. The friendly patio becomes the patio of death.
That can easily happen if we place plants outside too early or at least don’t climatize them first. The same can be said for those tomato seedlings. Taking them from the warm humid greenhouse to the garden is a harsh change.
We all can relate to temperature. It doesn’t take a genius to realize plants going from 70 degrees to perhaps 40 might encounter difficulty. Wind is also an issue we readily understand. Anyone living here knows damaging winds are always a concern.
Probably the most important variable and one often not considered is light. Many people think plants kept in a bright window have no problem adjusting to outdoor light. That’s ridiculous. Most plants in our greenhouse sunburn when we put them outside in nearly full sun.
Plants in full sun on a typical sunny day encounter a light intensity of about ten thousand foot candles. High interior levels might approach about a tenth of that. Even a sunporch which will drive you to another room can’t begin to match light intensities of outdoor conditions.
So how do we deal with it? We gradually harden our plants off. Place them on a covered porch or provide shade by placing them on the north side of the house. Otherwise they will sunburn, which usually won’t destroy them long-term. However, it does hurt their appearance. It might even force you to severely prune them back.
Many houseplants must be kept under low light conditions outside or they suffer. A structure with a solid roof is probably best for these. Ficus, Boston ferns and many palms can eventually handle nearly full sun.
Water is another concern. Plants kept outside will require more water than they did in their indoor location. This is especially true of plants in windy locations.
We must also be cognizant of rainfall. Too much water is usually a greater threat than too little. Feel the soil and keep an eye on the drain pans. Once root rot starts it is tough to control.
Also, when moving plants outside it is sometimes necessary to add a little potting mix. Most potting mixes are largely comprised of organic matter. This organic material decomposes over time.
Finally, if you don’t want to see a floor full of leaves this fall, you have to acclimate your plants in reverse when the weather cools. Ficus trees going from full sunlight to interior conditions might lose over half of their leaves. Even when well climatized they still might shed a third of them.
Perhaps this could discourage you from moving your houseplants. It shouldn’t. Houseplants can add to our outdoor environment. All we have to do is think about what we’re doing. Plants adapt to changing environments. We just can’t force them to adjust too quickly.
Ted Manzer teaches agriculture at Northeastern High School (firstname.lastname@example.org).