Overwatering or Underwatering? I Got It Wrong for Months

My rubber plant was dying. Leaves turning yellow, dropping off one by one. The classic signs of a thirsty plant, I thought. So I watered it more.

It got worse.

More yellow leaves. More dropping. A weird smell from the soil. I watered even more, convinced it was drying out.

By the time I figured out what was happening, the roots were black mush. The plant was overwatered. Every time I added more water "to help," I was drowning it faster.

This is the cruel irony of plant care: overwatering and underwatering can look almost identical. And if you guess wrong, you make things worse.

Why this is so confusing

Both problems can cause yellow leaves. Both can cause wilting. Both can cause leaves to drop. Both can make your plant look generally miserable.

The reason is actually logical once you understand it.

When a plant is overwatered, the roots start to rot. Rotting roots can't absorb water. So even though the soil is soaking wet, the plant is effectively experiencing drought. It can't drink. The symptoms look like thirst because, at the cellular level, it is thirst.

When a plant is underwatered, the roots are fine but there's no water to absorb. The symptoms look like thirst because, well, it's actually thirsty.

Same symptoms. Completely different causes. Opposite solutions.

The one diagnostic that actually works

Forget the leaves for a moment. Check the soil.

This sounds obvious, but I spent months looking at leaves and ignoring what the soil was telling me. The soil doesn't lie.

Stick your finger an inch or two into the soil. What do you feel?

If it's wet or moist, and your plant looks sad, you're probably overwatering. The soil should not be constantly wet.

If it's dry all the way through, and your plant looks sad, you're probably underwatering.

That's it. That's the diagnostic. Everything else is secondary.

Overwatering: the silent killer

Overwatering kills more houseplants than underwatering. By a lot.

It happens because most of us, when we're not sure if a plant needs water, give it water "just to be safe." We see a slightly droopy leaf and reach for the watering can. We feel guilty for not paying attention, so we compensate with extra water.

The problem is that soil needs to dry out periodically. Roots need oxygen. When soil stays constantly wet, roots suffocate and start to rot. Fungi take over. By the time you see symptoms above ground, the damage underground is already serious.

Here's what overwatering looks like:

The soil stays wet for days after watering. You might notice little flies (fungus gnats) hovering around the pot. There might be a musty or rotting smell. The lower leaves start turning yellow and falling off, sometimes while still feeling soft and plump.

In severe cases, the base of the stem turns soft or black. Leaves fall off with barely a touch. The whole plant wilts even though the soil is wet (this is the cruelest symptom, because it looks exactly like thirst).

If you unpot an overwatered plant, the roots are brown or black, mushy, and smell bad. Healthy roots are white or tan and firm.

Underwatering: dramatic but usually fixable

Underwatering looks different once you know what to look for.

The soil is completely dry. Often it pulls away from the edges of the pot, creating a gap. The pot feels very light when you lift it.

Leaves droop, but they're not soft and squishy like with overwatering. They're more crispy. The edges go brown and papery. Some plants curl their leaves inward.

Here's the good news: an underwatered plant usually recovers quickly once you water it. Unless it's been neglected for a really long time, the roots are probably still healthy. They're just dry. Give them water and they'll bounce back, often within hours.

This is why underwatering is generally less dangerous than overwatering. A thirsty plant can usually be saved. A plant with rotting roots is in much more trouble.

How to tell them apart (the cheat sheet)

When I'm not sure what's going on with a plant, I run through this checklist:

First, check the soil. Wet soil with a sad plant means overwatering. Dry soil with a sad plant means underwatering. This catches most cases.

Second, feel the leaves. Overwatered leaves tend to be soft, limp, and may feel slightly swollen. Underwatered leaves tend to be dry, crispy, and papery.

Third, look at the color. Overwatering often causes yellow leaves that are still somewhat plump. Underwatering causes brown, dry edges and tips.

Fourth, smell the soil. If there's a rotting or musty smell, that's overwatering. Healthy dry soil just smells like... soil.

If I'm still not sure, I'll carefully unpot the plant and look at the roots. Mushy brown roots mean overwatering. Dry but intact roots mean underwatering.

Fixing overwatering

If you catch it early, just stop watering and let the soil dry out completely. Move the plant to a brighter spot (more light helps the soil dry faster) and improve airflow if you can.

If it's more severe, you need to deal with the root rot. Unpot the plant, wash off the soil, and cut away any roots that are brown, black, or mushy. Use clean scissors and cut back to healthy tissue. Let the roots air out for a few hours, then repot in fresh, well-draining soil.

After repotting, water very sparingly until you see new growth. The plant is vulnerable right now and doesn't have the root mass to handle much water.

Some plants don't recover from severe root rot. That's just how it goes. The earlier you catch it, the better the chances.

Fixing underwatering

This is usually easier.

Water thoroughly until water runs out the drainage holes. If the soil has gotten really dry and hydrophobic (water just runs down the sides without soaking in), try bottom watering: set the pot in a tray of water for 20-30 minutes and let it absorb from below.

Trim off any leaves that are completely dead and crispy. They're not coming back.

Give the plant some time. Most underwatered plants perk up within a few hours to a day. Some dramatic plants (like peace lilies and fittonias) recover so quickly it seems like a magic trick.

Why tracking helps

I mentioned that I got my rubber plant diagnosis wrong for months. Part of the problem was that I had no idea how often I'd actually been watering.

I thought I was watering "every week or so," but in reality I was watering much more frequently than that. A little bit here when I noticed it, a splash there when I walked by, more whenever the leaves looked slightly less than perfect.

If I'd been tracking my watering, I would have seen the pattern immediately. "Wait, I've watered this plant four times in two weeks? That's too much."

Now I log every watering in an app (I use Beflore). When a plant starts looking unhappy, I can look back and see exactly what I've been doing. The pattern usually reveals the problem.

The rule I wish I'd learned earlier

When in doubt, don't water.

Seriously. If you're not sure whether a plant needs water, wait a day or two and check again. An underwatered plant will tell you it's thirsty (drooping, curling), and you can fix it quickly. An overwatered plant may not show symptoms until the damage is done.

The risk of waiting is low. The risk of overwatering is high.

My rubber plant never recovered, but I haven't made that mistake since. Every time I'm tempted to water "just in case," I remember the black mushy roots, and I put the watering can down.