How to water a houseplant properly
Almost every plant that comes back to us in a paper sack was watered a little, often. The habit that fixes most of them is the opposite one: water thoroughly, then wait until the pot tells you to do it again. Here is how you decide when, and how much, using the same three tests we use on our own benches.
How much water, exactly
Water until it runs freely out of the drainage hole, then stop. That is the whole rule. In practice you are pouring about a fifth of the pot’s volume — a cup for a 4″ pot, two cups for a 6″, a quart and a half for a 10″ — slowly enough that it soaks in instead of running down the inside of the pot and straight out the bottom.
What you’ll want to avoid is the small splash every few days. It wets the top inch, the roots follow the water upward, and the bottom two thirds of the root ball stays dry and dies quietly. When someone tells us a plant has been sliding downhill for months on a careful little schedule, this is nearly always what happened.
Tip the saucer out afterward. Fifteen minutes is plenty of time for the pot to take back whatever it wants. A pot left standing in half an inch of water all week is the most common cause of root rot we see, and you won’t spot it at all if the saucer is a dark one.
Deciding when: three tests, in order of usefulness
1. Weight
Lift the pot the day you water it, then lift it again four days later. A pot that has used its water is startlingly lighter, and after two weeks of doing this you won’t need any other test. It is what we use on the two hundred pots in the shop, because it costs you half a second per plant.
2. The finger test
Push a finger in to the second knuckle — about two inches down, not the surface. Cool and damp: wait. Dry and crumbly at that depth: water it. The surface of a pot in a heated room goes dry within a day of watering and tells you nothing at all, which is why so many people end up watering twice as often as they need to.
3. A wooden skewer
For a big pot, push a plain bamboo skewer down to the bottom, leave it a minute and pull it out. Dark and clinging with soil means wet; clean and pale means dry. We keep one stuck in the big monstera by the door and glance at it on the way past.
About moisture meters. We bought three of the cheap probe kind in 2021 and tried them in the same 8″ pot within two minutes of each other. They read 3, 6 and “wet.” They mostly answer how tightly the soil is packed around the probe and how many minerals are dissolved in it, and in a bark-heavy mix like ours that makes them close to useless. If you already own one, use it to confirm what your finger told you rather than in place of it.
Winter watering table
These are our own intervals for a 6″ plastic nursery pot in the shop’s front room: around 60 °F at night, no forced-air heat, and the gray overcast that runs from November into March here. Take them as a starting point rather than a prescription — a warm apartment with a radiator under the window will run through water considerably faster.
| Plant | Nov–Mar | Apr & Oct | May–Sep |
|---|---|---|---|
| Golden pothos | 12–16 | 9–11 | 6–8 |
| Monstera | 14–18 | 10–13 | 7–9 |
| Snake plant | 56–70 | 30–40 | 21–28 |
| ZZ plant | 42–56 | 28–35 | 21–28 |
| Rubber plant | 16–20 | 12–14 | 8–10 |
| Wax plant | 28–35 | 18–24 | 12–16 |
| Calathea | 5–7 | 4–5 | 3–4 |
| Maidenhair fern | 4–6 | 3–4 | 2–3 |
Three things shift every row of that table at once. Terracotta instead of plastic: about a third faster. A pot too big for the plant in it: much slower, and this is where you are most likely to get into trouble. Forced-air heat blowing anywhere near the plant: faster, with drier air on top of it.
Telling too much from too little
Too much and too little both give you drooping, and both give you brown leaves, which is why guessing between them goes wrong so often. You tell them apart by the feel of the leaf and the smell of the soil.
| What you see | Too little | Too much |
|---|---|---|
| Drooping leaves | Limp but dry; firm again within hours of watering | Limp and soft, often yellowing; no change after watering |
| Browning | Crisp edges and tips, paper-dry | Soft brown patches spreading from the leaf base |
| Leaf drop | Oldest leaves first, from the bottom | Anywhere on the plant, several at once |
| Soil | Pulled away from the side of the pot | Still damp a week on; sour or earthy smell |
| Recovery | Fast, and complete | Slow; usually needs repotting into dry mix |
If the soil has shrunk away from the sides of the pot, pouring water in just sends it down the gap and out the hole. Stand the whole pot in a basin of water for twenty minutes instead, then let it drain properly. Once will do it — do not make a routine of it.
Keep a note, not a schedule
We are not going to tell you to water on Sundays. A fixed day is how a plant gets drowned in January and starved in July. What works is writing down the date you watered and the date anything went wrong — an index card taped inside a cabinet door is plenty — and then reading it back after six weeks.
Nearly everyone who tries this finds their real interval is nothing like the one they thought they were keeping, and that one particular plant has been getting a drink every time they walk past with the can for a different one.
Guide rewritten August 18, 2025. The winter table was measured again in February 2025 and the numbers held.