“One, we want brand new fresh soil that’s filled with nutrients,” says Greene in the latest episode of Greene Thumb by Well+Good, a series on the Well+Good YouTube channel. “The second reason—plants run out of space, and so you want to report them in something an inch or two bigger, so they can grow nice and tall.”
Just prior to the new growing season, late winter or early spring is the time of the year to repot a plant, according to Susan Spanger, professional gardener and floral designer of Bloomful Floral Design. There’s a good chance yours needs it, too: “The general rule of thumb is that young and fast-growing plants will need to be repotted every six months to a year, and older plants need to be repotted every few years,” she says.
There are more reasons to repot a plant aside from its age, though—Greene says your plant will tell you it needs a bigger home is by dropping leaves.
“The first sign is seeing equal rates of new growth and a couple of leaves falling off at the same time,” says Greene. This happens because the new roots are being squished by the old roots, she says. Roots desperately need additional space to stay healthy and grow.
“If a plant’s root system is confined to a container for too long, it can become root-bound. Simply put, most root-bound plants are those that have grown too large for their container or pot,” says Spanger. “You’ll know if this has happened if the roots have taken up too much space within the pot, forming a circular dense web of roots. Or, if the roots are protruding from the drainage holes or are too exposed with inadequate soil covering them.”
Additionally, the soil may start to change colors. “You might see the little white rocks called perlite, turning yellow or brown, and that’s a sign that it’s time for fresh oil,” says Greene.
But, if you’ve got a really massive plant, you may not need to repot it. I often get the question a lot, ‘Do I need to keep reporting my really massive plant?’ Not necessarily,” says Greene. “You may just need to replace the soil content. So one of the things you can try is adding topsoil.”
To make sure your plant thrives for years to come, follow these easy-to-follow instructions on how to repot a plant without killing it.
How to repot a plant without killing it
1. Choose the right pot
When you’re repotting your plant, you don’t necessarily need to move it to a bigger one. Sometimes your plant’s potting mix just needs to be refreshed to provide it with new nutrients. But if your plant is getting too big for its pot, choose a new one that’s only a little bigger. “You want to make sure you find the right size pot for your original plant,” says Greene. “Ideally you’re finding something with one to two inches in diameter of extra room.” If you choose a pot that’s too big, you run the risk of overwatering and root rot (the most common killer!), which is more likely when a plant is swimming in potting mix.
2. Buy the right soil
If you’re unsure which type of potting soil to buy, Spanger recommends a blend that’s 70 percent coarse-fibered peat moss ($7) combined with a 30 percent perlite ($16). “You’ll recognize perlite as the tiny, roundish white specks which introduce air into the soil amid the other components,” she says.
When repotting the plant, start by filling the pot a third of the way up with fresh soil to the pot. “That way it has room for all the new roots to grow,” says Greene. “How much soil you add is often a guessing game, but you can always add more.”
3. Inspect and loosen up the roots
Now that you have everything you need to repot your plant, you’re ready to get started. “Once it comes out of the [old] pot, you can inspect the roots and you can see that it’s perfectly in this cylinder shape, and ideally we want to untangle the roots so that it can grow out,” says Greene. “Roots can be kind of delicate, so you don’t want to pull too much. You can use your fingers to get rid of as much soil as you possibly can without disrupting the system. The reason we’re getting rid of soil is because we’re replacing it with new soil. ”
If your plant is super root-bound with a really tight root ball, Spanger you might need to use a clean knife. Simply make a few cuts on the bottoms and sides of the plant that allow you to loosen the roots up.
4. Put your plant in its new home
After you loosen up your plant’s roots, it’s time to repot it. “After filling the pot to the base with fresh potting soil, place the root ball on top in the center. You need to make sure the surface of the root ball is below the rim so it’s covered sufficiently with soil,” says Spanger. “Once it’s correctly positioned in the pot, gently place soil around and over the roots, giving them the ability to move and grow.”
When adding soil, you want to pat the soil down. “You want to do the finger test because if you put your finger on top of the soil and it falls through, the soil isn’t tightly packed enough,” says Greene. “Use two fingers to pat it down. Roots really enjoy tight, compact soil for them to grow into.” Leave about half an inch to a quarter-inch of space at the top so water doesn’t overflow over the pot while watering. “And this is the best time to center your plant,” she says. Finish by lightly watering your plant, then don’t water it again for at least a week to give it time to adjust.
Here’s how to keep your plants alive, according to a professional gardener. Then learn the six most common mistakes people make with their indoor plants.
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