What is fertilizer, and why do cannabis plants need it?

Fertilizer provides essential nutrients like nitrogen, phosphorus, and potassium to help cannabis plants grow strong, healthy, and produce high yields. In most grow setups, regular feeding is required to avoid deficiencies and promote optimal growth.

What nutrients are essential for healthy cannabis growth?

Cannabis needs macronutrients like nitrogen, phosphorus, and potassium, plus secondary nutrients like calcium, magnesium, and sulfur. Micronutrients such as iron, zinc, and boron are also vital for plant health and development.

When should I start feeding cannabis plants nutrients?

Start feeding once your cannabis seedlings develop their first true leaves. In coco or hydro, feeding may begin as early as day 7–10. In soil, wait until the plant shows signs of slowed growth or pale lower leaves.

What do NPK values mean on cannabis fertilizer?

NPK stands for Nitrogen (N), Phosphorus (P), and Potassium (K), the three primary macronutrients. Ratios like 3-1-2 or 1-4-5 guide what stage of growth the fertilizer supports—veg or bloom.

How do I know if my cannabis plant is overfed or underfed?

Check the EC/PPM of your runoff water. If it's much higher than your input, nutrients are building up—overfeeding. If it's much lower, your plant may be hungry—underfeeding.

Light Schedule Generator

Light. Data. Growth. Smarter cultivation starts here.

Grow Light Schedule Generator

Create a light schedule based on your growth stage and when you want lights to turn on each day.

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Grow Journal

Plan, track, and reflect on your grow. The Grow Journal helps you organize tools, notes, schedules, and specs — all in one place.

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Why Light Schedules Matter

Plants need consistent light cycles to grow properly. Sudden changes or inconsistent timing can cause stress and reduce yields.

Recommended Schedules

Seedlings/Clones: 16 hours ON / 8 hours OFF
Vegetative: 18 ON / 6 OFF
Flowering: 12 ON / 12 OFF

Use a timer to automate your light cycle and stick to it daily.

Tool by GrōHaus — helping growers dial in their light, space, and yield.