My summer container garden has a few annuals, but it’s more a mix of perennials, shrubs, vegetables, fruits, herbs, houseplants, and small trees. Every year a few of these plants outgrow their pots and need larger containers.
Unless it’s really cramped in the pot it’s in now, when I move a plant up in size it goes in a pot the next diameter up, usually only an inch or two bigger. Although smaller containers dry out faster, and require more frequent watering, don’t put a small plant in a huge container with the idea it will grow to fill it. The root system isn’t large enough to absorb all the moisture in the soil, and can lead to root rot.
Remember to consider the height of a container as well as its diameter when potting up.
When measuring for a larger pot, consider the diameter of the pot – the width as measured across the rim– but especially consider the depth. A pot may be wide, but not deep enough for the roots to expand.
And when choosing a pot, go for one with holes. Seems obvious, but there are lots of pretty containers out there to tempt your eye that don’t have them. Containers without holes are called cachepots and are not meant to be planted in directly, because excess water can’t drain and the plant will rot. If you love a particular pot, pot the plant in a smaller plastic container and slip it into the cachepot. Empty the cachepot of standing water every day.
The new pot should be clean. If it held a plant before, wash it, and then soak it in a solution of one part bleach to nine parts water for up to an hour. Then rinse the pot before refilling with soil. If it’s a terra cotta pot, soak in plain water for an additional 10-15 minutes after rinsing to be sure all the bleach has leached from the absorbent clay.
A rose, weigela, strawberry, and blueberry are some of the perennial plants moved to bigger pots this year.
I prefer one plant to a pot, and create vignettes by moving the pots around and setting them at different heights. Other people like to combine lots of plants in one container, but I find caring for them easier when there’s only one type in a pot.
How to Repot:
Water the plant before removing it from its present pot.
While I sometimes lay pieces of paper towels, newspaper or coffee filters over the drainage holes, especially if there are a lot of them, it isn’t necessary. Not much soil comes out of the holes anyway.
Put some moist potting mix in the new pot, enough so the roots can rest on the soil and still have room to grow down. The crown of the plant should be about an inch or two below the rim of the pot.
Take the plant out of its old container and examine the roots. Are any dead or rotted? Carefully cut those away. Gently tease out the white living roots from the rootball so they don’t grow in a circle. Center the rootball on the new soil and hold the plant upright while you backfill around the sides up to that inch or so from the rim. Be sure all the roots are covered – a very pot bound plant can have roots even growing on the soil surface.
Firm the potting soil gently. Don’t press out all the airspace. Water again, not too much, enough so the soil settles. Some gardeners use a vitamin solution like SuperThrive in the water to help with transplant shock, but it isn’t necessary.
Minimize stress by keeping the plant out of direct sun for a day or so. Wait a few days or a week before fertilizing to be sure it has successfully settled into its new home.
A hydrangea paniculata (center) and a male and female winterberry were repotted into containers that are two inches wider in diameter.
A question that frequently comes up: should you put gravel, packing peanuts, or anything in the bottom of the pot before filling it? There are two minds on this.
Gravel doesn’t help with drainage the way we’ve all been taught, and while some people use packing peanuts to keep their pots light so they can move them or don’t want to use lots of expensive potting mix, I’m no longer a believer. I don’t put anything but soil in the pot; I want to give my plants’ roots as much running room as possible. If you are using the properly sized pot for a plant or plants, you shouldn’t need to put filler in the bottom.
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By Justin Hancock, Monrovia Horticultural Craftsman
Photographs courtesy of Monrovia
Labor Day may represent summer’s unofficial close but now is a perfect opportunity to add late-summer perennials that will continue to beautify your landcare until fall arrives. click here for an article that identifies 9 perennials for late summer.
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