Calculator Inputs
Example Data Table
| Scenario | Vertical lift | Submersion | Insertion | Extra | Material | Safety | Recommended length |
|---|---|---|---|---|---|---|---|
| Herbs in a self-watering pot | 12 cm | 5 cm | 8 cm | 3 cm | Cotton cord | 1.25 | ≈ 35.0 cm |
| Tomato bucket, deeper media | 18 cm | 6 cm | 12 cm | 4 cm | Felt strip | 1.30 | ≈ 49.0 cm |
| Indoor planter with long routing | 10 cm | 4 cm | 6 cm | 8 cm | Microfiber wick | 1.20 | ≈ 33.0 cm |
Examples are illustrative. Your best setting is confirmed by observation and adjustment after a few days.
Formula Used
Minimum physical length
Lmin = Lift + Submersion + Insertion + Extra
Recommended length
Lrec = Lmin × Safety
Material adjustment (practical)
Safetyeff = clamp(Safety ÷ CapillaryRating, 1.00, 2.00)
Lrec,adj = Lmin × Safetyeff
Capillary rating is a simplified score reflecting how easily a material stays wet and lifts water. Use it as guidance, not a laboratory value.
How to Use This Calculator
- Select your unit system and wick material.
- Measure the vertical lift from reservoir waterline to the root zone.
- Choose submersion depth so the wick stays wet as water drops.
- Set insertion depth to place moisture where roots will grow.
- Add extra slack for bends, knots, and secure placement.
- Pick a safety factor. Start around 1.25 for most setups.
- Optionally enter diameter and daily demand to estimate wick count.
- Press Calculate. Download results as CSV or PDF if needed.
After setup, check moisture for 2–3 days. If the top stays dry, increase insertion depth, wick count, or diameter. If the mix stays soggy, reduce wick capacity or lift.
Practical capillary lift limits
Wicks move water by capillary action, but vertical lift reduces delivery. Measure lift from the reservoir waterline to the moist zone you want near the roots. Higher lift often needs more wick capacity, not just more length. If lift is high, add wicks, increase diameter, or lower the reservoir.
Material choice and reliability
Materials wet out and clog differently. Cotton and felt usually prime quickly, while durable synthetics can resist rot and fraying. Keep one material per container when testing so results are comparable. The calculator’s material adjustment adds margin when a material wicks less efficiently.
Matching delivery to plant demand
Demand changes with sun, heat, wind, pot size, and growth stage. Use the daily demand input as a planning estimate, then confirm with observation. If the pot dries out, increase wick count or diameter first. Length helps routing and stability, but it does not guarantee higher flow.
Routing, submersion, and safety margins
Submersion depth keeps the wick tip wet as the reservoir drops. Insertion depth places moisture where roots can access it, and extra slack prevents tension that shifts placement. A safety factor buffers measurement error and real-world variability such as compaction, salt buildup, or partial air gaps.
Example data
- Lift 12 cm, submersion 5 cm, insertion 8 cm, extra 3 cm, safety 1.25 → recommended ≈ 35 cm.
- Lift 18 cm, submersion 6 cm, insertion 12 cm, extra 4 cm, safety 1.30 → recommended ≈ 49 cm.
Field checks and seasonal tuning
Check moisture at two depths for three days. If the lower zone is wet but the top stays dry, push the wick deeper or add another. If the mix stays saturated, reduce wick capacity or improve aeration. Recheck when seasons change because demand can shift fast. Record adjustments to repeat success later.
FAQs
1) What wick length does this calculator recommend?
It combines lift, submersion, insertion, and routing slack, then applies a safety factor and a material adjustment. The result is a practical cut length you can install without strain or dry breaks.
2) Does a longer wick increase water flow?
Not necessarily. Flow usually depends more on lift, diameter, and how well the wick stays wet. Add length for routing and stability, but increase diameter or wick count when delivery is low.
3) How do I choose a safety factor?
Use 1.15–1.30 for most containers. Go higher for hot, windy sites, longer routing, or when measurements are uncertain. After a few days of observation, tune the value to match moisture levels.
4) How deep should the wick sit in the reservoir?
Aim to keep the tip submerged even when the reservoir is low. A deeper submersion reduces the chance of air exposure, which can interrupt wetting and temporarily reduce delivery.
5) How many wicks should I use?
Start with one for small pots and low lift. If the estimated daily demand exceeds one wick’s delivery, add a second wick or use a thicker wick. Multiple smaller wicks can be easier to position.
6) Why is the soil surface still dry?
Surface dryness can be normal while roots stay moist. If plants wilt or the root zone is dry, increase insertion depth, add a wick, or reduce lift. Also check for hydrophobic media that resists wetting.
7) What maintenance helps keep wicks working?
Rinse or replace wicks if you see salt crusting, algae, or reduced flow. Flush the reservoir periodically and avoid letting the wick dry completely for long periods, which can slow re-priming.