AI and I talked about using weight to measure dry/wet. I bought I thought a reasonable scale but it can help me use the good points of the almost optimal one...
Hmmmm... well we got "NUTRI FIT Digital Bathroom Scale for Body Weight Loss Watchers Electri Scales, 50g/0.1lb Discrepancy, Clear Backlit LCD Display and Step-On Techhology, 2*AAA Batteries Included, 330lb/150kg, Jet Black"
ChatGPT said:
Thought for 28s
Nice snag. That bathroom scale will work—just know it’s a blunt instrument. Resolution ~0.1 lb (~45 g) isn’t lab-grade, but for 5-gal fabric pots the weight swings are big enough to be useful if you set it up right.
Make it reliable
- Hard, level surface. Tile/concrete/wood, not carpet.
- Flat top: Put a plywood square or shallow tray on the scale so pots sit stable. Write its weight on tape (e.g., “Board = 1.6 lb”).
- Mark foot positions on the floor so the scale always sits in the exact same spot.
- Kill “smart-step” memory: Step off fully between readings and let the display clear.
Find your anchors (per pot)
- WET (field capacity): Water to light runoff, wait 30–45 min, weigh.
- DRY (safe-dry): Let it get feather-light and top inch dry, not droopy, weigh.
- Set threshold: Water when weight ≈ DRY + 50% × (WET − DRY). (Seedlings: use 30–40% instead.)
Example (bathroom-scale friendly)
- Board = 1.6 lb (subtract this every time, since you can’t TARE).
- Pot WET (with board) = 19.8 lb → 18.2 lb pot.
- Pot DRY (with board) = 16.4 lb → 14.8 lb pot.
- Diff = 3.4 lb → Threshold ≈ 14.8 + 0.5×3.4 = 16.5 lb.
- Round to the scale’s step: 16.5 lb is your “water now” number.
Two accuracy hacks (optional)
- Human-tare trick: Weigh yourself, then weigh you + pot, subtract. Cheap scales are more linear at higher loads.
- Median of 3: Take three quick readings, write the middle value. It kills random blips.
Daily rhythm (fast)
- Weigh each pot once per day, same time.
- Don’t chase ±0.1 lb noise—look for trend. If you lost ~1.5–2.0 lb in a day, that’s a thirsty day; if it barely moved, hold water.
- Log: Date, pot weight, irrigated (Y/N), notes (leaf posture, PPFD tweaks).
Red flags the scale will catch
- Carly claw/dark + small weight loss → likely too wet / N high → lighter feeds, let it dry to threshold.
- NL5 perk returns + steady weight swing → root zone recovering, keep PPFD ~625 top until she’s consistent.
- Goth near chop → you’ll see daily loss taper slightly as she finishes—don’t overthink it; go by trichs.
Calibrate once with water jugs
A sealed gallon =
8.34 lb. Stack a gallon + a quart, confirm the scale reads ~
10.4–10.5 lb. If it’s off, note the offset on tape (“+0.1 lb”).
If the bathroom scale starts to annoy you, a $30–$50
30–50 kg bench/postal scale (1–5 g resolution) is the endgame. But for now: board on top, anchors set, threshold rounded to the nearest 0.1 lb—you’re in business.