Tips for Growing Chrysanthemums Indoors

Mums don’t make good full-time houseplants, but you can certainly enjoy them inside for part of the year. You can bring outdoor potted specimens indoors to overwinter and keep the store-bought plants alive for planting out in spring.

While it is possible to keep them in the home all year long, they might not bloom.

In our guide to growing chrysanthemums, we cover how to cultivate these charming late-season bloomers in your landscape.

This article discusses how to grow mums indoors. Here’s what I’ll cover:

Can Mums Grow Indoors?

There are numerous species in the Chrysanthemum genus, perennials that are part of the Asteraceae family.

Those typically grown in the home garden are cultivated hybrids, divided into 13 classes or classifications.

The hardy garden types that we plant out in spring, bloom in late summer to fall in a variety of colorful shades. Hardy in Zones 4 to 9, many garden varieties can also survive in Zone 3, with a little winter care.

There are also florist or exhibition chrysanthemums, showy, delicate types used extensively in the cut flower industry, which require careful cultivation and lack the cold hardiness of the garden varieties.

You can learn more about the different types of chrysanthemums in our guide.

When you buy potted chrysanthemums at the store in the fall, they are almost always in full bloom.

Usually, these have been cultivated in greenhouses and the grower encourages the chrysanthemums to flower by giving them growth hormones or by careful manipulation of artificial light to stimulate blooming.

But here’s the caveat. After they stop flowering, mums often won’t bloom again if kept indoors or if they do, the flowers will be sparse.

The reason is that these are what are known as “short-day” plants, which means they need relatively short periods of light – under 12 hours – to trigger flowering. They also need cool temperatures below 60°F for a few weeks to signal to the plants that it’s time to start producing buds.

Unless you keep that thermostat extremely low during the winter, your house probably doesn’t have the right temperatures to encourage your chrysanthemum to produce new buds and blossoms.

You can manipulate the light exposure by putting them in the dark for about 14 hours and in light for nine hours over the course of two months. Then, put them in at least 13 hours of light and 11 hours of dark for another few months.

If you leave them outside all year long, this happens naturally. But when you keep them indoors, there generally isn’t a large enough shift between light and dark and cool and warm to encourage blooming.

On top of this, the potted mums that you find at the store in fall typically aren’t the same types that grow so gorgeously in the soil in the garden. They’re less hardy, for one, and are sensitive to drainage and light.

So yes, you can grow chrysanthemums indoors, but they probably won’t bloom unless you put them outside during the summer months. You’ll need to enjoy them for the foliage, which is beautiful on its own. It’s also delicious in tea.

How to Grow Indoors During the Winter

Whether you are bringing home a potted mum in bloom from the store or taking your outdoor chrysanthemums indoors for the winter, place them as close to an exterior window as possible.

South-facing is best, but east- or west-facing works, too. Just don’t rely on a north-facing window to provide sufficient light or your chrysanthemum will become pale and leggy.

Indoor chrysanthemums require a lot less water than those growing outdoors in the garden. This is because there is less wind and sun inside, so evaporation is slower and the plant takes up less water and fewer nutrients during the winter.

Let the top few inches of soil dry out before you add more water. Overwatering is a quick way to invite diseases or even kill your plant.

Once the last predicted frost date in your neck of the woods has come and gone, you can work on moving your plant outside.

If you’re keeping your chrysanthemum in a container rather than planting it out in the garden, spring is the time to repot.

Choose a container one size up from what the plant is currently growing in, and ensure that the new pot has drainage holes. The material the pot is made from doesn’t matter. If you’re reusing an older container, be sure to wipe it out with soapy water first.

Then, and this is important, harden off the mum for a good week or two.

Your plant is used to living in the protected environment of your home. There’s no harsh wind or other kinds of environmental conditions that outdoor chrysanthemums face.

So you need to reacclimate it. Think of hardening off a bit like taking your plant to base camp for a bit before you let it scale Mount Everest.

To do this, take the plant outside and place it in a protected area in direct sun for half an hour to an hour on the first day. Then, take it back inside. The next day, add a half hour to an hour. Keep adding a half hour to an hour until the mum can stay outside for eight hours.

At that point you can leave it out there in its container or transplant it into the ground.

How to Grow Indoors Year Round

If you want to keep the chrysanthemums indoors year-round, you can do so, but just remember that the plants might not flower or, if they do, the display won’t be anything like you’d see outside.

Chrysanthemum leaves are edible, but they aren’t as tasty as the type that is grown specifically for food.

Known as shungiku in Japan, C. coronaria​​ produces more tender, less pungent leaves than the hybrids we grow in the garden. C. indicum is typically grown for its flowers, which are dried and used in tea.

You can technically eat the leaves and flowers of the hybrid types, but it’s best to sample just a small amount first to see if you have any sensitivities or allergies and avoid it altogether if you’re allergic to species in the Asteraceae family.

If you decide to keep your plants indoors, proper watering is the key to success. Mums don’t like to have their roots dry out, but conversely it’s easy to overwater indoor specimens. Let the surface of the soil dry out between watering.

Better yet, stick your finger into the soil down to the second knuckle. Does it feel like a well-wrung-out sponge? Excellent. If it feels soggier than that, stop watering until it dries out.

If the soil feels dry to the first knuckle, add water. If you notice that the soil feels wet down at the tip of your finger, you might have drainage issues. If this is the case, pull the plant out of the pot, make sure the drainage hole is unblocked, and replace some of the soil in case it has become compacted.

You’ll also need to fertilize your chrysanthemums regularly. A general-purpose or houseplant-specific fertilizer is perfect.

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