Why do we put houseplants in small pots indoors, yet outdoors plants grow in huge amounts of soil no problem?

You’ve probably been warned not to ‘pot up’ too many sizes at once. Or been told you’ve got your plant in too big a pot and that’s why it’s on struggle street. This is why…

The #1 reason is YOU. Yep, as Taylor would say: I’m the problem, it’s me. A pot size that’s a snug fit around the roots helps protect our plants from us over-watering them. Give a plant a too-big pot and the risk of root rot from over-watering goes way up.

Too-big pots also make it harder to keep the soil the same moisture level throughout. Some roots could be stuck dying a slow death in a patch of soil that’s dried out, while the rest have wet feet.

That’s because of the combo of the pot keeping water in, and all that soil holding a lot more water. A small plant in a big pot means way more moisture around those roots.

Too much water for too long means not enough air, and that puts the welcome mat out for root rot causing bacteria and fungi that love wet conditions with low-oxygen.

But in nature outdoors, there’s no pot keeping water in and water doesn’t just sit and stay where it’s put. In fact, you normally have the reverse problem and have to switch to a more moisture-retentive soil to hold on to the water for longer. Shift that plant inside with the same soil in a pot and say hello to root rot (and goodbye to your plant).

That’s also why chunky, airy, soil-free mixes are so popular for most indoor plants. My faves are Wildvine’s Hoya and Aroid Blend, and Bio Leaf’s Aroid and Hoya Mix. Both are soil free (and made right here in New Zealand by fellow small, family businesses).

Another problemo with too-big pots is when you go up too many sizes at once you can temporarily slow or stunt your plant’s growth. Actually your plant is getting busy below ground filling up all that space with roots, but above ground there’s no action. If you’ve ever heard of people’s plants going ‘dormant’ for weeks or months after repotting, that’s a common reason why.

Play it safe. Go small :)

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