Croton: what your moisture meter reading means

The healthy band for a croton, on whichever scale your meter prints — and, more usefully, what the same number means in different situations.

Percent (0–100)

38–65%

what the four-in-one we recommend prints

Ten-point probe (1–10)

4–7

if your probe prints a bare 1–10 sweep

Analog dial

2–3

Moist to Wet — of 4 zones

That is the band you are aiming for, not a target to hit exactly. These ranges are published horticultural consensus and are deliberately banded wide — these are unpowered galvanic probes, two of them in the same pot routinely disagree, and fertilizer salt raises the reading with no extra water present.

Got the plant in front of you? Point your camera at it — Plant Tender names what is in the pot from one photo and gives you the numbers it wants. No account, no card.

What each reading means for a croton

A croton wants water below 38% and starts staying wetter than it likes above 65%. If your probe prints a bare 1–10 sweep instead of a percentage, that works out like this.

Reading	For this plant	What to do
1	Bone dry	Well past dry. Water thoroughly now — look for the whole plant drooping sharply, often within a single day.
2	Thirsty	Dry enough to water. Water on the next check unless you watered in the last day or two.
3	Thirsty	Dry enough to water. Water on the next check unless you watered in the last day or two.
4	In the healthy band	Inside the healthy band. Leave it — the useful question is whether this number is falling since last time.
5	In the healthy band	Inside the healthy band. Leave it — the useful question is whether this number is falling since last time.
6	In the healthy band	Inside the healthy band. Leave it — the useful question is whether this number is falling since last time.
7	Wetter than ideal	Wetter than ideal. Fine a day or two after watering; a concern if it has been a week.
8	Wetter than ideal	Wetter than ideal. Fine a day or two after watering; a concern if it has been a week.
9	Saturated	Saturated. If this has not fallen in several days, check drainage before you change anything else.
10	Saturated	Saturated. If this has not fallen in several days, check drainage before you change anything else.

Every row here is worked out from this plant's own numbers — a croton at 4 and a snake plant at 4 are in genuinely different situations.

The number depends on your soil, and most charts ignore that

A croton is usually in peat-based potting mix with perlite, kept evenly moist.

A croton lives at the other end of the light scale from most plants on this list. It needs strong light to hold its colors, and a plant in strong light uses water quickly, so in a sunny window in summer a croton pot can go from freshly watered to thirsty in a matter of days. It wants that soil evenly moist, not soaked and not dry, and it reacts to both extremes the same way it reacts to almost any upset: it drops leaves.

Adjusting for your mix

Peat mix in plastic: the range on this page applies as printed. Terracotta in a bright window: the clay speeds up drying on top of a thirsty plant, so check every couple of days in summer. Chunky or bark-heavy mix: drains too quickly for a croton; readings fall fast and the plant spends too much of its time near dry. In winter, when the light drops: the plant drinks much more slowly, and a summer watering habit carried into winter leaves the pot sitting at the wet end.

Plant Tender asks which of these your pot is in — dense potting soil, chunky aroid mix, bark / orchid mix, semi-hydro / pon, succulent / cactus grit — and applies the adjustment for you, along with a probe-depth target from your pot size.

Where to put the probe

Halfway down, midway between the stem and the pot wall. Crotons usually arrive with a tight, dense root ball, and just after a repot the old root ball and the new mix around it can read quite differently. Until the roots have grown out into the new soil, take the reading close to the stem, where the roots actually are.

How a croton actually fails

Leaf drop, and it comes in two kinds that call for different responses. After a change, such as the trip home from the store, a new room, a cold draft or a sudden drop in light, a croton sheds leaves within days, often colorful and healthy-looking ones, while the soil reads perfectly normal. After a dry spell, the leaves droop hard first, then the lower ones crisp at the edges and fall a few days later. The meter tells you which one you are looking at. The first needs patience and a stable spot; the second needs steadier watering. Changing the watering to fix the first only adds a second upset.

Common situations

I just brought my croton home and it is dropping leaves. It reads 5.

That is the move, not the water. Crotons drop leaves after almost any change in light, temperature or position, and the trip from a bright greenhouse to a living room is a big one. A 5 is inside the band, so the soil is not the cause. Put it in the brightest spot you have, keep it away from drafts and heating vents, keep the reading in the band, and resist moving it again. New leaves usually follow once it settles.

It reads 3 and every leaf is drooping.

That one is thirst: on this page 3 is in the thirsty rows. Water thoroughly until it drains from the bottom, and the leaves should lift again within hours to a day. Next time, water as the reading approaches the bottom of the band, around 4, before the droop. A croton that goes through repeated hard droops tends to lose lower leaves a few days after each one, even when it seems to recover.

My croton has turned mostly green and reads 7 most of the time.

Both come from the same cause: not enough light. New croton leaves come in plain green in a dim spot, and a plant that is not getting enough light uses water slowly, which is why the pot sits at 7. That is the top of the range printed at the head of this page, but past about 65%, which the table puts in the wetter-than-ideal rows. Move it somewhere much brighter, gradually over a week or two so the leaves do not scorch, and water less until the reading is falling normally again. The color comes back mostly on new growth rather than on leaves that have already gone green.

One reading can't be trusted. How fast the pot dries out can.

Everything above is really one argument: a single number from a cheap conductivity probe is not a measurement, it is a data point with a large error bar. Fertilizer salt raises it. Air gaps in chunky mix lower it. Probe depth moves it several points. Two meters in the same pot disagree.

What survives all of that is the trend. The same meter, in the same spot, in the same pot, read over a few weeks, tells you how fast your croton in this specific mix in this specific room actually dries — and that is the thing that answers "do I water it", which no chart can do for you.

Stop looking it up. Point your camera at your croton.

The bands above are for croton in general. Plant Tender gets there from a photo instead: one shot of what is actually in the pot, and it names the plant and gives you the soil-moisture, soil-temperature and light numbers that plant wants. Your first scan needs no account and no card.

Scan a plant — free, no account

Already know what it is? Save it to Plant Tender and it remembers what your croton read last time, then tells you water or leave-it-be — so you are reading a trend instead of interpreting one number in isolation. Free for your first three plants.

Ranges come from Plant Tender's per-species dataset, which is version-controlled and reviewed in public — Codiaeum variegatum, 38–65% moisture, 61–78°F soil temperature, bright indirect to direct light.