How to Read a Feed Chart: A Grower’s Guide to Nutrient Schedules

Every nutrient line — from cannabis brands to greenhouse-vegetable programs — ships with a feed chart: a week-by-week schedule telling you what to mix and how much. Used well, it’s a huge head start. Followed blindly, it’s one of the fastest ways to burn a crop. This guide breaks down how to actually read a feed chart, and how to adjust it for your water, plants, and room.

What Is a Feed Chart?

A feed chart is the manufacturer’s recommended nutrient schedule, laid out by growth stage or week. It tells you which products to use, in what amounts (usually milliliters per gallon or liter), and often a target EC or PPM for each stage. Think of it as the recipe book that comes with your nutrients — a proven baseline the company arrived at through testing.

Anatomy of a Feed Chart

Most charts share the same structure. Read across the columns and down the rows:

What you’ll see	What it means
Weeks / stages (columns)	The timeline — seedling, vegetative weeks, then flower/bloom weeks through flush
Base nutrients (e.g., A & B, Grow/Micro/Bloom)	The core NPK + micronutrient foundation, fed every stage
Additives / boosters	Supplements (cal-mag, silica, bloom boosters) added at specific stages
Dose (mL/gal or mL/L)	How much of each product per unit of water
Target EC / PPM	The nutrient strength the finished mix should land at

Understanding why each element is there helps you adjust with confidence — Penn State Extension’s primer on essential nutrients and their functions is a great companion read.

The Golden Rule: It’s a Starting Point, Not Gospel

Here’s the single most important thing to know: feed charts are written for ideal conditions the manufacturer can’t see in your room. They assume a certain base-water quality, a certain environment, and average genetics. Your source water, temperature, humidity, and specific cultivars can all shift what your plants actually want.

That’s why experienced growers treat the chart as a baseline to dial in, not a rule to obey. Many start at 50–75% of the listed strength and work up while watching the plants — it’s far easier to add nutrients than to recover from burning them.

How to Dial In Your Feed Chart

Know your base water. If your source water already carries dissolved solids, that EC stacks on top of what you add. Growers on hard water often start with RO to get a clean, predictable baseline.
Measure the finished mix. Mix to the chart, then check EC and pH before feeding. Adjust to hit the target range for the stage.
Read your runoff. Runoff EC higher than input means salts are building up (back off or flush); much lower means plants are eating everything (feed more).
Watch the plants. Tip burn means too hot; pale, slow growth can mean too light. The plants are the final word.
Taper at the end. Charts ramp nutrients up through bloom, then cut them for the flush — see when to stop feeding.

Feeding by Growth Stage

Nutrient needs shift dramatically across the life cycle. Vegetative growth wants more nitrogen; flowering shifts toward phosphorus and potassium. A good chart already reflects this, but pairing it with crop steering — adjusting how you irrigate alongside what you feed — is where real control comes from.

Rows of the Paragon's clear injection dosing pump heads that meter each nutrient into the feed — Automated dosing — like the Paragon’s injection pumps — delivers every nutrient in your feed chart to the milliliter, feed after feed.

Common Feed Chart Mistakes

Running 100% out of the gate. The listed strength is often a ceiling, not a floor. Ease in.
Ignoring your base-water EC. Additives stack on whatever’s already in the water.
Stacking every additive. More products isn’t more yield — it’s more risk of lockout and imbalance.
Never measuring. A chart without an EC/pH meter is a guess. Michigan State Extension’s guide to pH management and plant nutrition is a solid reference.

Feed Chart FAQ

Should I follow my feed chart exactly?

Use it as a starting point, not a rule. Manufacturers write charts for ideal conditions; your water, environment, and genetics may call for less (or occasionally more). Start conservative and adjust from EC and plant response.

Why start at 50–75% strength?

It’s much easier to add nutrients than to fix nutrient burn. Starting lighter lets you find your plants’ real appetite without risking damage.

Do feed charts work for crops other than cannabis?

Yes. Every fertigated crop — greenhouse tomatoes, leafy greens, berries — uses the same concept: a stage-based nutrient schedule you dial in to your conditions.

Turn Your Chart Into Consistent Feeds

A feed chart is only as good as your ability to deliver it precisely, every time. That’s exactly what automated fertigation does — the Paragon mixes and delivers your recipe to the milliliter across every zone, so your dialed-in chart actually reaches every plant. It’s the backbone of consistent commercial fertigation. Talk to our team to put it to work.