BONSAI PLAN+T
SUSTEE Japanese Soil Moisture Indicator | Watering Checker
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A colour cue for everyday watering
Wondering whether to water today? Let the soil give you a useful cue.
Made in Japan, the SUSTEE soil moisture indicator stays in the pot and shows moisture changes through its viewing window. No batteries needed — a helpful reference for caring for bonsai and potted plants.
- Blue: moisture is still available; watering is generally not needed.
- Fully white: a watering cue. Check your plant's needs and the actual condition of its growing medium.
- Leave it in the pot: observe it daily without removing and reinserting it.
Sold individually · S / M / L · White / black / green
Buy 3 or more for free shipping; mix sizes and colours. Delivery arrangements are confirmed via WhatsApp.
Choose by soil depth
Check the actual depth of soil inside your pot, then choose a size that can be inserted to its markers. Pot height, soil depth and full stick length are different measurements.
| Size | Selection guide | Full stick length |
|---|---|---|
| S | Consider for small or shallow pots | 12 cm |
| M | Everyday plant pots; check actual soil depth | 18 cm |
| L | Consider for large, deep pots | 25.5 cm |
Stick length is not the required pot depth. The soil must accommodate the insertion section so its surface sits between the two triangle markers. Keep the water inlet buried, with the viewing window and upper vent exposed. Do not bury the entire stick.
The manufacturer does not publish a single centimetre-based pot-depth range for each size. Check the actual markers and soil depth; contact us if a shallow pot cannot accommodate the insertion section.
Manufacturer's pot-diameter reference
S: 6–9 cm; M: 10.5–18 cm; L: 18–36 cm. These are general pot-size references, not insertion depths. Wide, shallow bonsai pots still need a soil-depth check.
Not sure which size to choose? Send us a pot photo and its actual soil depth for advice.
How to use
- Insert into the soil: choose a position near the roots, with the soil surface between the two markers.
- Water thoroughly on first use: water evenly and wait for the window to turn blue. Response time varies with size and growing medium; it can take about an hour in some conditions.
- Observe daily: leave it in the same pot. When fully white, check the plant and water as needed. Do not keep adding water simply to maintain a blue window.
Before you buy
Can I use it in a shallow bonsai pot?
Consider size S, but check that it can be inserted to the markers. Contact us first if your pot is particularly shallow.
Can I use it with akadama or coarse growing media?
Particle size and contact affect the response. Very coarse, fast-draining media can limit water uptake. If the soil is wet but the window remains white, check the position and core before adding more water.
Can I move it between pots?
SUSTEE needs to stay in the soil to respond over time. It is not an instant probe. We recommend a separate indicator for each pot.
When should I replace the core?
Typically after about 6–12 months, depending on growing medium and use. Reuse the casing with the matching refill size.
Product information
Brand: SUSTEE
Made in Japan
Sold individually
Plants and pots shown in photographs are not included. Availability is shown for each selected variant.
