Overwintering Plants Indoors
In fall, a gardener's thoughts turn to saving favorite plants for the next year. Perennials and shrubs are hardy plants and can be left to fend for themselves with little more than fall clean up and, in some cases, a nice mulching. Annuals are going to have their last hurrah and will eventually succumb to the freezing temperatures of fall nights. This leaves us with tropicals, tender perennials and a few assorted plants that can be overwintered in the house.
Which plants are good candidates to bring inside for the winter? Many tropicals and plants sold as houseplants will do fine throughout the winter indoors.
There is nothing wrong with trying to bring any plant inside for the winter. Gardening is, after all, all about trying new plants and moving old plants to new places. Sometimes it works, sometimes it doesn't, but half of the fun is in trying!
What is it about the inside of a house that makes it difficult for many plants? You probably would guess that low light levels are one potential problem. Your home has lower light levels to begin with and the short days of fall and winter also contribute to the problem. The second reason many plants don't adapt to indoor conditions is low humidity. The air inside your home, especially in winter, tends to be very dry. Many plants do not deal well with low levels of humidity.
If you would still like to overwinter a plant in your home, however, abide by the following simple steps for the best result.
The first thing to do is choose the plant or plants you want to bring inside. Be sure to bring your plants inside before frost has damaged the foliage. Choose only healthy plants to bring inside as the stress of the move will likely be the final blow to struggling plants. If the plant is already in a pot, you can skip to the next paragraph. If the plant is in the ground, use a sharp spade or shovel to dig it up. You will want to try to get a good chunk of the root system. Remove part of the garden soil and place the plant in a pot, filling it in with a good potting mix; garden soil tends to lack enough air space for container plants. Keep the soil level even or very slightly above the level of the garden soil. If you bury a plant too deep in soil, it will not happily thrive.
If the plant has been in a rather sunny area, you can help decrease the shock it will experience coming indoors by placing it in a shady spot for a week or so. This will get it used to lower light levels and make the transition easier.
Next decide if the plant needs to be pruned before you bring it inside. Plants can generally be pruned back by as much as 1/2 of the plant without damaging its health. When pruning, use a sharp pair of pruning shears or scissors, or a sharp knife.
Once you have your plants potted and pruned, it is time to inspect them for debris, disease and insects. Remove any dead foliage or other debris from the top of the pot. Dead and decaying foliage is a hiding place for insects and an incubator for diseases. Clean plants tend to be healthier.
Check for any insects and treat as necessary. It is important to remove insects before plants come inside, because insect populations tend to increase and spread quickly indoors. In the case of larger insects, like beetles, you can remove them by hand. If you see aphids or spider mites you will want to use a spray to kill them. If the infestation isn't large you can probably remove them by spraying the plant with a mixture of soap and water. A few drops of dish soap in lukewarm water can be a very effective means of controlling insects. Spray the plant until it is dripping with the soapy mixture - be sure to get the underside of the leaves and the stems. If you can visibly see insects (like aphids and spider mites), you may want to take a damp cloth and gently wipe off the infested leaves and stems. For obvious reasons it will be easiest to use this method outside. If the plant is badly infected with aphids, mites or scale you should consider discarding the plant rather than trying to bring it indoors.
While checking for insects also look for disease. Common diseases include mildews and viruses. Mildew will generally be a white or grey powdery substance. Viruses will often cause the plant to have foliage that is yellowing, mottled or stippled, where the foliage just doesn't look right. Mildew can be treated with the same soap and water mixture used against insects. If you think your plant has a virus, discard it and start new next spring.
Water the plant thoroughly before bringing it inside. Be sure to allow a good amount of water to run out of the drainage hole. This will help flush out any excess buildup of salt or fertilizer in the soil. You may want to follow this flush with a light fertilizer application.
Move your plants indoors and place them in areas with bright light. Sun porches are great for overwintering plants. If you don't have a sun porch, you can also use grow lights for supplemental light.
To help combat low humidity in your home, place a shallow pan filled with gravel underneath your plants (it is best to buy gravel from the store where it will be clean; if you get gravel from your driveway be sure to wash it well). Add water to the gravel. This water will evaporate, keeping the area right around your plants more humid. You can also spray the area with a spray bottle a couple of times a week to help increase humidity.
While the plants are inside, do not fertilize them unless the plant is growing vigorously - then fertilize lightly about once a month. You will also need to be careful not to over water. Plants inside will not use as much water as they did outside. Water only when the top of the soil is dry to the touch. When you do water, try to dampen the whole root zone (a bit of water should drain out of the bottom of the pot). It is very easy to accidentally kill your plant with kindness by over-watering it.
Plants in lower light situations will have a tendency to stretch and become lighter green in appearance. Don't worry too much about this; if you can keep your plant alive until spring, you can deal with the stretched plant then.
In spring, when the days start to get longer, you should see your plant begin to grow more vigorously (or again, some plants may not grow throughout the winter). When this new growth starts, fertilize lightly with a water soluble fertilizer. Prune your plant back if it is looking stretched and unhappy. Your plant is likely to begin using more water at this time so be sure to keep an eye on how quickly it is drying out. Lightly pinching new growth will encourage your plant to branch.
Once you start getting warm days, you may want to start introducing your plant to outdoor conditions. Gradually introducing a plant to cooler temperatures (hardening off) will help it acclimate to outdoor conditions. Moving plants outside during the day and inside at night will help them harden off. Plants are like people; that first 40-degree day seems awfully cold. However, after a week of 40-degree temperatures, it begins to feel nice. Once the threat of frost has passed, you can place the plant outside permanently.
Things to Remember When Overwintering Plants Indoors:
1. Choose only healthy plants.
2. Bring Plants indoors before frost damages foliage.
3. Treat for disease and insects before bringing plants indoors.
4. Once indoor, place in bright areas and add humidity using pebble trays or spray bottles.
5. Be careful not to over water.
6. When active growth starts in spring, fertilize and prune as needed.
7. Introduce your plants slowly to outdoor conditions again in spring.
First published on www.provenwinners.com