A New Pot? Why Not?
Thursday, May 17, 2007
Most houseplants begin active growth in the spring, which makes this the ideal time to repot them.
How to tell if a plant needs repotting
Look for signs of root crowding -- roots growing out of the drainage hole or over the lip of the pot. In extreme cases, bottom root growth will raise the plant up noticeably. In addition, a root-bound plant will need watering repeatedly because of the increased ratio of roots to soil.
Turn the pot and plant upside down, ease the root ball from the container and see if root growth is excessive. On large or stubborn plants, run a knife around the inner surface of the pot and have a helper hold the lip of the pot while you remove the plant.
A noticeable buildup of fertilizer salts on the sides of the pot, and salts or moss on the soil surface, suggests a need for a fresh growing medium and a repotting.
Get a new pot
If you are tired of the old pot and want to treat yourself to something nicer, now is the time to do that. Your new pot won't need to be freeze-resistant because your plants must come indoors before the first autumn frost. However, it will need to drain. Look for drainage holes on the bottom. You could return the plant to a same-sized pot if you trim the roots a little, but this seems like a missed opportunity. Move up to the next size or two, for example, from a 10-inch pot to a 12-inch, from a 16-inch to an 18-inch, etc. That will give you two or three years before repotting again. Increasing the pot size too much will encourage excessive soil moisture and run the risk of root rot.
Place gravel or clay shards at the base of the pot to provide for drainage. A clay pot absorbs water and should be thoroughly soaked before repotting to prevent soil wicking.
Brush away much of the old soil, the point of the exercise being to provide a fresh growing medium. Don't use garden soil or pure peat moss. Invest in a high-quality potting mix.
Place the crown of the plant no lower in the new pot than its previous level, and make sure that the roots have full contact with the fresh mix. Tapping and shaking the container occasionally as you fill it will allow the soil to settle. Take this opportunity to trim and tidy some of the foliage, and give the plant a good watering.
Watering and feeding
Resume a regular watering schedule once the soil begins to dry, and fertilize at recommended rates when new growth is evident. Fertilizer can be applied as a slow-release granular feed or as a liquid. Synthetic and organic feeds are available.
Many houseplants love the increased light and humidity levels found outside the home in spring and summer, but most will become stressed if placed in full sunlight. A sheltered, shady patio is ideal, or at least an area that will be protected from afternoon sunlight. Do not put a saucer under the pots: This will cause waterlogging.