Crop Steering Guides Compared

Most of what growers know about crop steering comes from a handful of free guides published by nutrient, substrate, sensor and controller companies. They agree on the structure and disagree on the numbers. Here is what each one covers, where they differ and where to get the official copy.

Links go to each publisher's own site, except the Growlink e-book: we could not find a public download on Growlink's site, so we link to a copy we host. IXYZ is not affiliated with any of these companies. Checked September 2026.

At a glance

Athena: Precision Irrigation Strategy

The guide most people mean when they search for an "Athena crop steering guide". Written by Jay Yokiel for Athena Ag, it covers terminology, pot sizing, climate by stage, the P0 to P3 irrigation phases and a stage-by-stage steering plan.

• Substrate: 100% coco in 4 to 10 L pots, or rockwool blocks on slabs. Smaller pots are recommended because they dry back faster.
• Schedule: vegetative in veg; generative in flower weeks 1 to 4 (stretch); vegetative in weeks 5 to 7 (bulk); a mix in weeks 8 to 10 (finish): low substrate EC with a larger dry-back.
• P1: shots of 2 to 6% of substrate volume every 15 to 30 minutes, usually 5 to 9 shots, until field capacity and some runoff.
• P2: maintenance shots after a 3 to 5% dry-back, roughly every 45 minutes to 2 hours. May be skipped if P1 alone hits the target.
• Substrate EC: 3 to 5 in veg, 4 to 10 in stretch, 3.5 to 6 in bulk (mS/cm, pore-water EC).
• Worth knowing: Athena calls the drop after lights-on and before the first shot "additional dry-back". It warns against running high substrate EC after stretch.

Official PDF from Athena support · Support article

Grodan: Grow Guide, Cannabis Edition

The reference for rockwool. Written by the stone wool manufacturer, it focuses on how blocks and slabs hold and release water, and on sizing shots and emitters.

• Shot size: 3 to 6% of total connected stone wool volume per shot. 1 to 2% is "extra small", 3% standard, 4 to 6% large. Count the block and the slab together.
• First shot after lights-on: 0 to 1 h vegetative, 1 to 2 h neutral, 2 to 4 h generative.
• Last shot before lights-off: 0 to 2 h vegetative, 2 to 3 h neutral, 3 to 4 h generative.
• Emitters: 0.3 to 0.5 gallons per hour, with flow measured regularly.
• Worth knowing: the guide treats low-flow, pressure-compensating emitters as essential, and checks that pumps and injectors match their pressure range.

Official PDF (2024 edition) · Crop steering chapter only

Growlink: Crop Steering, A Comprehensive Guide

An e-book by Marcus Baldinger and Kevin Crouch, a commercial cannabis cultivator. It pairs climate and irrigation recommendations for each steering direction and explains the reasoning in plain language.

• Vegetative: 78 to 85 °F, 70 to 85% RH, VPD 0.6 to 1.1 kPa, shots of 1 to 3% of substrate volume, dry-back of 1 to 10%, substrate EC of 2 to 4.
• Generative: 65 to 78 °F, 45 to 70% RH, VPD 1.0 to 1.5 kPa, shots of 3 to 6%, dry-back of 15 to 30%, substrate EC of 5 to 12.
• Worth knowing: the dry-back figures do not say whether they are VWC points or a percentage of peak. Check the difference before using them.

This is version 1.4 of the e-book, created in December 2021. It may be out of date: Growlink's current recommendations and products may differ. Check Growlink's site for their latest guidance.

Growlink Crop Steering e-book, V1.4 (PDF, 77 pages, 15 MB) · Growlink: the 4 phases of irrigation · Growlink crop steering guide (knowledge base)

AROYA: crop steering and dry-back guides

Web guides from a substrate sensor company. They are the clearest explanation of dry-back itself, including the fact that growers calculate it in more than one way.

• Explains both absolute dry-back (VWC points) and dry-back relative to field capacity.
• Gives a general root-zone temperature range of 18 to 24 °C.
• Covers the full set of steering levers, not just irrigation.

Crop steering: the ultimate guide · Mastering dry backs

Agrowtek: Crop Steering Irrigation application note

A technical note from a controller maker. It treats the steering day as a control sequence and gives the formulas behind it: VWC, runoff percentage, final dry-back target and shot time.

• Vegetative: P1 shots of 3% with 1 point dry-back between them; P2 target 55 to 70% VWC; overnight dry-back of 10 to 15% of field capacity.
• Generative: P1 shots of 4 to 8%; P2 shots and dry-backs of 4 to 8%; overnight dry-back of 20 to 30% of field capacity.
• Worth knowing: recommends ending the final weeks generatively for density. Athena's schedule does the opposite with EC, which shows how unsettled the finish still is.

Official application note page

Where the guides disagree

Each guide was written for its publisher's products and conditions. None of them is wrong, and none of them was written for your room. Our crop steering chart puts the common ground on one page.