The days are getting noticeably longer now, and even though our snow-covered gardens are weeks away from spring planting, my houseplants have noticed the difference and are starting to put out some new growth. March is a good time to direct my yearning to garden towards my houseplants while I wait for spring to arrive outdoors.
During the depths of winter most houseplants go into a slowed state of growth, so pruning or dividing them then would not be such a good idea. But now that they are waking up and putting out some new growth, they will be able to respond to the stress of pruning and re-potting with no problem. These practices do cause some stress to the plants but it also induces them to push out more new growth in response, so this really is the ideal time to work on your houseplants.
There are three main tasks to consider this time of year: repotting, pruning and propagating. Each task can fill a whole column so I will just touch briefly on each one, and a huge variety of plants can be grown indoors, so my comments cannot apply to every houseplant you might have, but they should apply to most.
The best way to tell if a plant needs re-potting is to knock it out of its pot and take a look at its roots. If you do this carefully you can just slide it right back into the pot. Ideally, the pot should be about an inch wider than the root ball of the plant. Do not double the size of the pot, increase the size gradually so the roots and top growth can stay in balance. If the root ball is packed solid with roots, it’s time to pot up. If the soil is loose around the roots, or if a good amount stays in the pot when you pull the plant out, the pot is either just right or a bit too big. Consider re-potting into a smaller pot if the roots are filling less than half of the current pot.
So many folks hate to prune their plants, thinking it’s hurting them, but actually the opposite is true; pruning is invigorating, not harmful. Yes, the plant may look a little rough at first after you’re done but it will quickly push out lots of new, more vigorous growth as a result.
Long, vining plants such as pothos and ivy may look their best at the tips of their shoots, but bare and straggly at the base of these shoots, closest to the pot. It’s hard to cut off that nice growth at the tips, but it’s the only way to make the plant thicken up closer to the pot. Be ruthless and cut the stems quite short, up to the rim of the pot. Save the best tips for rooting to make more plants and soon you’ll end up with plenty of spare plants to share with friends.
Most people like to root cuttings in a glass of water. While this does work in many cases, it’s really best to stick the cuttings into moist potting mix and let the roots form right into the medium where they’ll be growing.
For vining plants I like to stick three to four cuttings in a four-inch pot, and for larger plants like geranium I stick one cutting per pot, then I cover the pot loosely with a clear plastic bag. I keep this out of direct sunlight until the cuttings are rooted, then remove the bag and set the plant in the kind of light it likes. This method works well for Christmas cactus, peperomia, goldfish, and many other types of plants.