Taking Water Management to a Higher level or how do you train someone to water correctly? Will Healy Senior Technical & Research Manager Ball Horticultural Company

kills more seedlings & plants than anything else we do! Incorrect watering kills more seedlings & plants than anything else we do!

Plant Demand Water Consumption Floral Initiation Flower Expansion Ship Stage 1 Pinch Stem Elongation Stage 2 Stage 3 Plant

PWS!* Pay to Water Pay when @Dry Target Paranoid Watering Syndrome Dr Will, Dr Will Help me please - I suffer from….. PWS!* Pay when @Dry Target Pay to Water Paranoid Watering Syndrome

Water Knowledge Pyramid Quantitative aka Data based Qualitative aka Opinion based Climate Plant Demand Where to Water How Much to Water When to Water-How Dry? Language of Watering W1-W5

What is this?? What are you trying to do?? 5 1 2 3 4

Pyramid Level 4 Where to Water 3 Dimensional Space! Edge Middle Depth W2-3 W5-2 W3-5 W4-5 Highly Branched Root System Top Horizontal Root System Water Root System Vertical Root System

Drying out a cell Drying out a cell is due to evaporation of the water from the soil Water loss is sigmoidal over time Incremental loss is slowest at level 5 & 1 Incremental loss is linear with time at level 4-2 If water loss is 200-300 g per day then the loss of 800 g (level 42) will take 2-4 days.

Non-Uniform Begonia Note that dry down below the target dry levels (white line) of the early stages of development which caused the root damage early in production.

Horizontal Rooting (top wrap) Why do we see top rooting with minimum roots at the bottom? Even though the last days went 4→2 the first 5 days after germ (circle) stayed evenly moist which started the horizontal root development Failure to dry keeps top wet (Blue) Failure to go wet allows salts to build on bottom of plug (Red)

Watering Success Draw the roots to the bottom of the container. Saturate to a level 4 (bottom drip) Dry to a level 2 Train your watering pattern to a 4-2 It’s the drying that promotes rooting Water to get to the next dry point

‘Tools of the Trade’ 5 gpm 3 gpm 19 lpm 12 lpm 2 gpm 0.5 gpm 8 lpm

RH + Temp  VPD

What drives water loss from the container? B ET Evaporation Transpiration Change in tray weight will predict the ET rate Weigh the same container in afternoon & morning. Night ET = afternoon-morning Day ET = morning-afternoon Night Water Loss 200+ gm – Rapid drying 100-200 gm – Ideal 50-100 gm – Too wet issues < 50 gm – Tip abortion

Managing the Water in the Container How much water (weight) is lost each day? How much water (weight) is lost each night? How much water weight must I add to reach the target weight tomorrow? How much water weight must I add to get water to the bottom of the cell or pot? It’s not the how wet or dry but how long does it take to get to the next watering time

Water Knowledge Pyramid ET tells the story Climate Drive the roots to the down Plant Demand Set your wet target time Where to Water Set your Dry target How Much to Water Qualitative & Quantitative When to Water-How Dry? Language of Watering W1-W5