I often say that nature never created a houseplant. The plants we call "houseplants" or "indoor plants" are native to various, generally tropical, areas of the world. And in all cases, their natural habitat is outdoors.
It's not surprising, then, that houseplants moved outside during the warm summer months grow better and more vigorously than those kept inside year-round.
I often provide some R&R for my houseplants by moving them outside this time of the year. Houseplants may be moved to locations outside and left there for a few months, or until the weather begins to cool in the fall.
Plants form an important part of our indoor environment, so you may not want to move them all outside. But houseplants that have not been doing well, those that you want to encourage to grow or bloom better, or those that need rejuvenation will particularly benefit from some time outside.
Moving houseplants outside can be tricky because the plants become acclimated to lower light conditions while indoors.
So, at first, move houseplants to shady locations outdoors where they receive no direct sunlight. Plants that favor low light conditions can stay in those locations all summer.
Others can be gradually introduced to direct sun over a couple of weeks. Eventually, sun-loving houseplants, such as bougainvillea, hibiscus, plumeria, tibouchina, cactuses and some orchids, can be placed in locations that get six hours of direct sun or more.
(Be careful: Even sun-craving houseplants may burn if put in a sunny location as soon as they leave the house.)
Once outside, most houseplants would enjoy a good rinsing off with the garden hose. Months of indoor dust can be cleaned away by doing this.
Plan your repotting carefully
Now is also a good time to begin to look at which plants might need to be repotted.
If you will need new pots, check out local nurseries and pick some out. It is so much better to have the pots you need on hand when you decide you want to repot.
Don't forget the principle of hand-me-downs. I always had to wear my older brother's clothes when he outgrew them -- same thing with houseplants. As you shift one plant into a larger container, you can repot another into the now-available pot. So, you might not need a new pot for every plant you intend to repot.
You can tell a plant needs to be repotted when the plant fills up the container with roots -- a condition called root bound or pot bound. Look for a solid mass of roots on the soil surface or roots coming out of the drainage hole.
You can also lay the pot on its side and gently pull the plant and its rootball out of the pot to check the roots. If the plant does not slide out of the pot, set the plant back upright. Use a long knife and run it around between the sides of the pot and the root ball. Lay the pot back on its side. The plant should slide out with the root ball intact.
If you see a solid mass of roots, it's time to repot, but you don't necessarily have to. A root bound condition tends to slow down the growth of a plant. This sounds bad, but if the plant is already about as big as you want it to be, it may be an advantage. Being root bound means you have to water more often and fertilize occasionally, but if the plant is healthy and looks good, repotting is optional.
Eventually, though, the root bound condition will begin to affect the overall health of the plant. You will notice yellowing older leaves with little new growth to replace them. At that time, repotting is recommended. Plants that you are trying to encourage to grow should be repotted as soon as the roots fill the pot.
Water more often outdoors
Houseplants that are moved outside will likely need to be watered more frequently than when they were indoors.
Air movement, brighter light and faster growth all contribute to faster water usage by plants in containers.
Feel the soil often and monitor the soil moisture carefully until you reestablish a watering schedule. As the temperatures rise, you may need to water even more often.
Daily watering is not unusual, especially for plants in smaller containers and those located in areas with more light.
Plants that have been repotted, on the other hand, may need to be watered less often. The additional soil space will not dry out as rapidly as when the plant was pot bound. Once again, monitor the plant carefully until an appropriate watering schedule can be established.
Plants moved outside for the summer often grow vigorously, and if you want to encourage that growth, it's a good idea to fertilize them.
Fertilization is especially important to plants that are growing in soilless potting mixes, are root bound or that seem pale and lack vigor.
It is optional to fertilize plants that appear healthy, vigorous and are already as large as you want them to be.
You do not need a bunch of different fertilizers for your houseplants. One general-purpose houseplant food will do the trick.
One option is to use your favorite soluble fertilizer (one with a 20-20-20 analysis is good for just about everything). These are typically applied every two weeks through the growing season.
Slow-release and houseplant spike formulations, on the other hand, feed slowly over a long period and do not have to be reapplied constantly.
Soluble fertilizers are great for gardeners who like to fuss, slow releases for those who would rather not have to remember to fertilize every two weeks.
If you've got some houseplants that have been languishing indoors, try giving them some time outside this summer.
You will often be amazed as nature transforms your houseplants into the happy, vigorous plants they were meant to be.
DAN GILL'S MAILBOX
Loved your article on Angelonia. Sounds like a great plant for our garden (corner house, lots of sun). We are having a difficult time locating the plant in Metairie. Any suggestions? Many thanks.
David and Cindy Hoerner
You need to make sure the nurseries where you shop know that you want this plant, so they will know there is demand. Always make sure you ask to see the manager/owner and tell them that you came in looking for this excellent plant and are disappointed that they did not have it available. When it comes to Louisiana Super Plants selections, such as the Serena angelonias, ensuring that plants are available at local nurseries is part of the program. A listing of nurseries participating in the Louisiana Super Plants program can be found at the website lsuagcenter.com/superplants.
What is the best chemical I can spray my crape myrtles with to prevent the leaves from turning black and (developing) a white powdery substance under the leaves? Your help would be greatly appreciated.
Good news, you don't have to spray: There is an excellent drench you apply to the roots. Look for products containing the insecticide imidacloprid, such as Bayer Advanced Tree and Shrub Insect Control, Ferti-lome Tree and Shrub Insecticide Drench or other brands.
Is it true that if you plant hotter peppers on the same row as sweet peppers, the sweet peppers will become hotter than usual?
Although peppers are self-pollinating and generally do not cross, sweet peppers and hot peppers belong to the same species and can cross with one another. However, the type of pepper produced by a flower is based on the genetics of the plant producing the fruit -- not by the pollen it was pollinated with. Say a hot pepper fertilizes the flower of a sweet pepper. All of the hot pepper genes from the father plant go into the embryo and the seed. The fruit, the pepper that we eat, is developed from the ovary of the flower of the mother plant. The pepper does not contain any and is not affected by the hot pepper genes that were in the pollen. The heat or mildness of the pepper itself is strictly determined by the genes of the mother. As a result, even if a flower of a sweet pepper is pollinated by and the eggs are fertilized by pollen from a hot pepper plant, it does not affect the fruit produced by the sweet pepper plant and will not make the fruit hot.
Now, if you plant the seeds inside that sweet pepper, then you will see the effect of the male parent's genes. The embryos inside the seeds inherited half of their genetic makeup from the male parent. That means it is entirely likely that plants grown from the seeds inside the sweet pepper may turn out hot. So, if cross-pollination does occur between a sweet and hot pepper, it does not affect the fruit produced, but certainly may affect the characteristics of the next generation grown from the seeds in the fruit.
Dan Gill is extension horticulturist with the LSU Ag Center.
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