When and why should you repot a plant
• Just because you WANT to!
• To check out the root system.
• To divide a plant to share with friends.
• It’s out growing the pot
• Getting rid of salt build-up (white, crusty salt build-up in the soil)
• All indoor plants need repotting from time to time. The frequency of repotting depends on the growth rate of the particular plant. Fast-growing plants may need repotting annually, while slow-growing plants may require repotting every two to three years. Some plants (e.g., amaryllis) also thrive when pot bound.
• Growth will be encouraged by moving plants into larger pots.
• You can replace poor soil during repotting.
• Examine the soil in the pot. If there is a small gap between the soil and the edge of the pot, the plant might need to be repotted.
• Soil turned into a brick!
What kind of soil should be used?
• I recommend using a commercial potting soil that contains a combination of organic material (usually peat moss) and inorganic material such as washed sand, vermiculite, or perlite. The organic materials will hold water and the inorganic materials will provide drainage and aeration. These materials are virtually devoid of essential plant nutrients, so fertilizers that include micronutrients are always added to commercial products.
• You can either purchase this yourself, or use what’s in the Potting Room in the big tub below the counter.
• Do not use garden soil because it is likely to contain plant disease organisms and provides poor drainage and aeration.} For that reason, NEVER, Never, Never put used potting material into clean potting soil ALWAYS discard used soil into the trash (compost). It is good for NOTHING, and perhaps HARMFUL!
• Pour some potting mix into a bucket or bowl and add an equivalent amount of warm water, then blend thoroughly.
How about pots?
• Use only pots with a drainage hole in the bottom.
• Unfortunately, some plant containers such as terrariums, plastic pots provided with bulb forcing kits or decorative gift plant containers do not have drainage holes. If you own such a pot and want to use it to grow plants, transplant your plant into a pot with a drainage hole. Then place the planted pot (with the drainage hole) into your fancy pot without the drainage hole.
• Previously used pots should be scrubbed with detergent and sanitized in a 10% chlorine bleach solution before reuse to minimize disease transmission.
• Plastic pots are easier to sanitize than ceramic pots or wooden boxes.
• Plants in plastic pots will not need to be watered quite as often as clay pots.
Check the roots
• To remove the plant from its old pot, slip your hand over the top of the pot, holding the plant’s stem between your fingers, and turn the pot upside down, striking the pot so it dislodges the plant from it’s pot.
• Examine the roots after the plant is out of the pot. The roots should appear firm and white or light-colored. Black, dark colored, squishy or smelly roots are symptoms of root disease caused by overwatering or poor drainage. Rotted roots should be trimmed with a clean, sharp knife or pruners. If there are just a few sickly roots, simply prune them off. If most look sickly, then discard the plant but try making some stem or leaf cuttings first.
• Roots may also be pruned to keep a plant at a certain size. To do this, you trim off up to 1/3 of the bottom of the rootball. Again, only use clean, sharp tools.
• If thick roots totally encircle the plant, cut away a 1/2- to 1-inch slice of roots and soil with a sharp knife — not only all around the pot, but also from the bottom
• If roots have grown in a circular pattern at the bottom of the old pot, clip them. Break the root ball apart slightly to ensure that the root system will move into the new soil.
• The next step is to cover the holes in the bottom of the pot with a paper towel or coffee filter to keep soil from washing out the hole.
• All plants require good drainage for a healthy root system.
• To repot, put some medium in the bottom of the new pot. Set the rootball in the middle of the new medium. Fill medium around the sides between the rootball. Do not add medium above the original level on the rootball, unless the roots are exposed or it has been necessary to remove some of the surface medium. Gently press or firm the medium with your fingers.
• if you are moving a plant into a larger pot for more rapid growth, the new pot should be about one inch larger in diameter than the old pot.
• Remove about one-third of the old potting mix from the root ball, loosening it gently with your fingers, a stake, a pencil, or a chopstick inserted straight down into the roots. The goal is to have the newly repotted plant sit in the new container at the same level it was in the old container with some new soil around and on top of the old soil ball.
• If white salts, moss or other growth is on the surface, scrape this off before planting and replace with fresh potting mix. Don’t bury the stem base. Firm the new soil around the old soil ball, being careful not to pack it down too tightly.
• After watering and settling, the soil medium level should be at least one-half inch from soil to rim.
• Keep the plant out of the sun for a few days after you repot it.
• Water well, let drain, and you’re done!
What if the plant is too large to re-pot?
If a plant is too large to repot, “top-dress” it every few years. To top-dress, scoop out the top two or three inches of soil, taking care not to disturb too many of the roots. Refill the pot to its original soil level using a fresh potting mixture.
You may want to remove a piece, or divide the whole plant into sections. Sometimes there are obvious shoots that can be easily separated. Many vines like the pothos or an upright cane like the dumb-cane or umbrella plant, may drop leaves as they get older. If your plants get leggy, you may just need to root a section of stem and then pot this, discarding the original plant after your cutting is rooted.
To root a stem section of about 3 to 4 inches or so, simply remove the lower leaves, only leaving a few near the tip. Some such as the pothos or coleus,P root easily in water, others you may want to stick in a rooting medium which drains well and has lots of air space.
Good rooting media are perlite, vermiculite, and a 50:50 combination of these two, or even moist sand and peat moss mixed.
Place cuttings in pots, then enclose loosely in a plastic bag out of direct sun. Check daily for moisture, misting if needed, but don’t keep too wet. After several weeks, gently tug or pull on the cutting, and if it doesn’t pull out, it is likely rooted enough to pot.
Read Full Post »