September is your last chance to divide these 7 houseplants – and this easy propagation method will double your plants instantly

Propagating houseplants is not only a hobby of mine but a task I see as essential to get done before the coldest temperatures settle in. While milder temperatures still linger, us indoor gardeners can take advantage and divide clump-forming houseplants for new plants instantly.

Many of the best indoor plants are best propagated by division, rather than being the easiest houseplants to grow from cuttings. While spring is often the ideal time for division, ahead of new growth, September offers a unique window to get new plants for free. It's a month where temperatures are still mild and houseplants haven't yet entered dormancy, providing a last chance to divide them before the coldest temperatures arrive.

Although division can seem intimidating, it's actually a very straightforward propagation method. It does require some expertise, but once you get the hang of it, you'll be tempted to divide your entire indoor garden. Here, I share five houseplants to divide in September so you can double your collection ahead of fall and winter.

7 houseplants to divide in September

Propagating houseplants by division is much the same as dividing plants in the yard. You'll need a few essential gardening tools to help you get this job done, including a garden knife (from Amazon) or trowel and houseplant potting mix (from Amazon).

1. Blue star fern

This houseplant to divide in September is at the top of my list because my blue star fern has doubled in size this year.

If you have a blue star fern, you'll notice rhizomes that grow on the soil surface or just below. They're identifiable as fleshy, hairy horizontal rhizomes that tend to spread across the surface. Above, sits a mound of this iconic blue houseplant foliage.

This makes dividing blue star fern one of the easiest houseplants to propagate in fall and winter, and it can be fundamental to supporting their health if they're showing signs of becoming pot-bound.

You simply need to carefully remove your fern from its pot and clean its roots and rhizomes of soil.

Look for natural separations between the rhizomes, which is where you'll make cuts using a garden knife. You want each section to have at least two fronds and a healthy rhizome and set of roots.

Before repotting each new section in well-draining houseplant soil, prune damaged houseplant roots. Take care, however, not to remove too much of the root system as these plants can be sensitive to disturbance.

Water each new plant well, using this houseplant watering can from Amazon.

2. Monstera deliciosa

In September, your Monstera deliciosa is still actively growing, making it a good time to divide it and successfully propagate your monstera.

Waiting until late fall and winter would be a mistake, as it could disrupt your dormant monstera too much and hinder its health, possibly resulting in both the original and new plant struggling.

While it is possible to propagate a monstera from a stem cutting, its much quicker to divide it. Although, this will only work if your monstera has grown large enough to have two or more separate clumps.

You'll want to gently remove your monstera from its pot and wash away the soil from its roots. Look for natural separations in the root ball, i.e. where there is a new clump of foliage.

When I've previously divided my monstera, I've found you can sometimes just tease the roots apart. But, if your plant has grown to be quite large, you can use something like this garden knife from Amazon to carefully cut and separate clumps.

Make sure each section has multiple healthy stems on it, and even a couple of aerial roots if possible. You can then pot them up – using DIY monstera potting mix – and water well to help each plant settle into its new home.

3. Peace lily

If you're keen to propagate your peace lily and it isn't currently flowering, this is the month to do it.

It's best not to divide indoor flowering plants while they're in bloom because it can cause stress, kill off the flower, and stunt the plant's growth.

September is an ideal month for dividing a non-flowering peace lily because temperatures are still mild and the plant's growth is slowing down.

Use a similar technique to dividing a monstera: remove your peace lily from its pot, clean away soil, and gently tease apart the root ball until you have new sections.

One trick to make this division easier is watering your peace lily well the day before you divide it. The soaked roots will be softer to work with, making it easy to pull them apart.

This can be an excellent way to revive a droopy peace lily if it has become overcrowded by its luscious foliage. Creating new plants from the original will give each one sufficient room to grow and it will improve air circulation, reducing issues like mold and mildew.

4. Snake plant

This is a houseplant I often recommend to beginners because it's one of the most low-maintenance indoor plants to grow. In the right conditions, a snake plant can grow a couple of meters tall and this sword-shaped foliage can soon become overcrowded. That's where division is beneficial.

To propagate a snake plant by division, you should remove it from its pot, clear away the soil, and start to separate the entangled roots. It's possible to tease them apart, but you may also find you need to cut them with a knife or trowel.

When dividing your snake plant, you want to aim for each new section to have its own robust root system and at least three leaves.

You can then pot them up in a well-draining and even sandy potting mix, like this succulent and cactus potting mix from Amazon.

Use this opportunity to also prune away any damaged snake plant foliage, to give your new plants a better chance of survival with healthy leaves. The leaves of snake plants tend to be thicker, so you might need pruning shears like these from Amazon to make clean cuts.

5. Spider plant

You can propagate a spider plant at nearly any point in the year, thanks to its easy and resilient nature. Although you might be more familiar with propagating it from cuttings of the 'spiderettes' they produce, division is also a good option if your plant is becoming overcrowded.

You'll need to ensure your spider plant has distinctive separations before jumping in with division. You can do this by looking at the crown of the plant and seeing if there are multiple clumps.

Then, remove it from its pot, clear soil off its roots, and simply tease the clumps apart. Each new plant should have a fairly robust root system, ready for planting up.

I often find that spider plants become pot-bound quite quickly, which they don't like (this might even be the cause behind your spider plant turning yellow). This will make it harder to pull apart the separate clumps, so consider the help of a garden knife at this stage.

I've previously divided my spider plants and it's resulted in a boost of growth and lots more spiderettes – I've even allowed them to stick around to grow a hanging spider plant.

6. Areca palm

If you want an instant indoor jungle, dividing your areca palm is the quickest way to do it. These tall indoor plants have luscious fanned foliage that can create canopies in your home as they grow taller. Becoming overcrowded, however, may impact their ability to perform their best, including damage to their fronds.

Of course, you need to be careful when dividing your areca palm because it's a larger plant to handle and you don't want to cause damage to their delicate leaves. Consider lying down this houseplant potting mat from Amazon to keep the process tidy.

Just like dividing peace lilies and snake plants, dividing an areca palm consists of teasing apart the root ball where the plant has natural separations. Looks for stems that have their own set of roots.

To help your areca palms recover from this division, prioritize a warm and bright location. You might even want to consider using a grow light (from Amazon) to provide extra light as your plants settle in.

7. Pothos

Pothos is a collectible houseplant, with so many pothos varieties to choose from. You can quickly multiply your collection by dividing these plants. In fact, it's possible to propagate a pothos at any point of the year, but the active growing season (from spring to fall) is an ideal window.

To propagate your pothos by division, look for natural separations. This is much easier to spot on a trailing indoor plant like pothos, where different vines typically have their own roots.

You should be able to gently untangle and pull apart pothos roots with your hands. Make sure to pot up each new section with a DIY pothos potting mix, or a commercially available pothos potting mix (like this from Amazon).

To provide some extra warmth while your pothos plants establish, try using this plant heat mat from Amazon, and water each new plant well.

FAQs

Should I fertilize houseplants after dividing them?

No, it is not wise to fertilize houseplants after dividing them. This is because division is already a disruptive process for your plants and it's best to let them settle and establish in their new pots after using this propagation method. Adding fertilizer into the mix risks adding stress, which may cause a number of problems from wilting to yellowing, and stunting growth. Rather, wait until your houseplant has established and until the active growth season (spring and summer) to feed your plants.

Another reason I make use of these houseplants to divide in September is because it gives them time to establish ahead of gift-giving season, so I can then share my houseplants with loved ones.

If you're keen to experiment with other propagation techniques, check out our guide to growing plants in water and speeding up houseplant propagation.