Things that affect the watering rate of plants

You have to water more often when...

• ...the pot is small.
• ...the pot is shallower.
• ...the potting mix drains fast.
• ...the soil-to-root ratio has more root.
• ...there’s a lot of green mass.
• ...the plant is in a growth stage.
• ...the weather is hotter.
• ...the weather is drier.
• ...the plant position gets more sun, heat, or dryness.
• ...the plant species is tolerant of wet soil (=vibes well with wetter soil life).
• ...the plant species is thirsty.

You have to water less often when...

• ...the pot is oversized.
• ...the pot is taller.
• ...the potting mix holds water.
• ...the soil-to-root ratio has more soil.
• ...there’s little green mass.
• ...the plant is in a rest stage.
• ...the weather is colder.
• ...the weather is wetter.
• ...the plant position gets more shade, coldness, or humidity.
• ...the plant species is sensitive to wet soil (=vulnerable to wetter soil life).
• ...the plant species is adapted to little drinking.

It is impossible to mentally calculate all these variables; therefore, regular schedules for plant watering are unreliable. The reliable way is to stick a finger deep into the hole and see if it's wet. Be careful of tall pots, which depending on other conditions may be dry in the top but still wet in the bottom (watering from the bottom prevents this issue).

Another technique for small and medium pots is to lift them up. They’re a lot heavier when the soil is holding water. Do this a couple times and you’ll see, it’s really obvious if they’re dry or not.

If in doubt, err on the side of too dry. But the ideal is to avoid going full bone-dry, as that hits the soil life negatively.

If your plant is doing badly and you're a beginner, you're probably giving her too little sun. If you're sure you're giving her enough sun (are you really sure tho), watering issues are #2. If your well-lighted plant is doing badly, stick a finger in the hole.

• If it's wet and the plants look awful, change your watering approach to water less often. In bad cases, unpot the plant, wash the roots, clip any soft or rotten root, and repot in new soil.

• If it's super dry and the plant looks flomped or wilting, water it throughly and immediately, and take care to not let the soil dry to much. it might be a lot easier to repot in more soil / slower-draining soil, or alter any of the other factors above, than trying to keep demanding watering schedules. You can also buy or DIY a self-watering pot; you add water in a bottom container, and it wicker upwards as the soil dries.

It's very unlikely that the problem is the soil being too acidic/basic or lacking nutrients etc. Consider that it's possible to grow any plant healthy and fine in pure water with minimal nutrients (aquaponics) or in a shallow bowl of rocks (bonsai). Even tiny rocks have enough macro- and micro-nutrients to feed plants for years—as long as the minerals are made soluble & edible to plants, which only happens if you got a healthy soil ecosystem metabolising it, which needs good watering. Investigate the sunlight and watering first; these are the big causes of problems.