Calculator
Choose a container shape, enter dimensions, and set your growth conditions. The layout becomes three columns on large screens, two on tablets, and one on phones.
Formula used
- Top area: round = π × (diameter/2)², rectangular = length × width (cm²).
- Volume: liters = (area × depth) / 1000, because 1000 cm³ equals 1 liter.
- Plant count: plants = ceil((area × coverage%) ÷ spacing²).
- Control Index: starts at 100 and subtracts penalties for crowding, shallow depth, vigor, sun extremes, and temperature stress.
- Pruning interval: weeks ≈ base ÷ (vigor × sun factor × coverage factor × trimming style).
How to use this calculator
- Select your unit system and container shape.
- Enter container dimensions and depth from the rim down.
- Set coverage and spacing to match your harvest goals.
- Choose vigor, sun, temperature, soil, and trimming style.
- Press calculate and review the control notes and schedule.
Example data table
| Units | Shape | Diameter / L×W | Depth | Coverage | Spacing | Vigor | Sun | Temp | Plants | Control Index | Prune |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Metric | Round | 30 cm | 22 cm | 80% | 20 cm | Medium | 6 h | 24°C | 2 | ~75 | ~2.7 wks |
| Imperial | Rect | 16×10 in | 10 in | 70% | 8 in | Slow | 4 h | 18°C | 2 | ~82 | ~3.3 wks |
Your recent calculations
| Date/Time | Units | Shape | Area (cm²) | Depth (cm) | Volume (L) | Plants | Index |
|---|---|---|---|---|---|---|---|
| No saved runs yet. Calculate once to start a history. | |||||||
Container Size Benchmarks
For patio control, a single mint plant performs best in 8–12 L of soil, roughly a 28–32 cm round pot at 18–24 cm depth. A rectangular 40×30 cm planter at 20 cm depth holds about 24 L, supporting two plants. Below 6 L, roots bind early, runners accelerate, and the calculator’s crowding penalty rises quickly.
Spacing and Coverage Targets
Spacing sets plant count from usable surface area. In containers, 18–25 cm spacing balances airflow and harvest density, while 65–85% target coverage keeps the surface shaded without letting stems mat into one aggressive carpet. If you want faster fills, raise coverage to 90% but expect shorter pruning intervals. For culinary harvest focus, keep spacing wider and coverage near 70%.
Control Index Interpretation
The Control Index begins at 100 and subtracts penalties for crowding, shallow depth, high vigor, and stress from sun or temperature. Scores above 80 mean stable containment with routine pinching; 65–79 suggests steady trimming and moisture checks; 45–64 calls for fewer plants or a larger pot; below 45 indicates rapid takeover risk. Use the index as a weekly signal rather than a one-time grade.
Pruning and Repot Scheduling
Pruning interval is calculated from vigor, sunlight, and coverage. Fast, sunny setups can shorten intervals to 1–2 weeks, while cooler, shaded pots often stay near 3–5 weeks. Pinching the top two nodes encourages branching and slows runner formation. When the index drops, the calculator recommends root pruning or repotting every 3–4 months to reset spread pressure.
Water Planning Using Weekly Demand
Weekly water is estimated from container volume, sun exposure, temperature, and soil retention. A 10 L pot in 6 hours of sun at 24°C often lands near 6–9 L per week, while sandy mixes can push higher. Coco blends hold moisture longer and reduce swings. Use the weekly figure to split watering into 3–7 checks, aiming for moist soil without standing water.
FAQs
What does the Control Index tell me?
It summarizes how easy your container setup is to manage. Higher scores mean more space per plant and less stress. Lower scores indicate crowding, shallow depth, or fast growth conditions that demand tighter trimming and repot timing.
How many mint plants should go in one container?
Use the recommended plant count from the calculator. As a rule, aim for about 8–12 liters of soil per plant. If volume per plant drops under 2 liters, reduce plants or increase container size.
Which trimming method improves control the most?
Pinch soft tips weekly during active growth, and harvest above a node to force branching. Remove long runners as soon as they appear. Consistent light trimming keeps mint compact and delays root binding.
How should I use the weekly water estimate?
Treat it as a planning total, then divide it into several checks. In warm, sunny weather you may water daily; in cooler weeks, every two to three days may be enough. Always confirm by feeling moisture 2–3 cm below the surface.
Does soil choice change the maintenance schedule?
Yes. Sandy or very fast-draining mixes increase watering frequency and can speed growth if constantly wet. Coco-heavy blends buffer moisture swings and may lengthen intervals slightly. Whatever mix you use, keep drainage holes clear and avoid standing water.
When is it time to root prune or repot mint?
If stems thin out, growth becomes sudden and sprawling, or the pot dries unusually fast, roots may be bound. Follow the suggested interval in months, and consider repotting sooner when the Control Index falls below 65.