Van Gogh’s Fertilizers and How to Pick a Cannabis Feed

This page used to recommend Van Gogh’s fertilizers and link to their shop. In October 2026 their website went offline, so we took the links out. If you came here for their feeding schedule, you won’t find it on their site any more.

You don’t need one particular brand to grow good cannabis. Any decent fertilizer works if you feed for the stage your plant is in and keep the pH right. Below is what to look for.

What a cannabis fertilizer has to supply

Plants need three main nutrients in large amounts: nitrogen (N), phosphorus (P) and potassium (K). The three numbers on a bottle, such as 4-2-6, tell you how much of each is in it.

• Nitrogen builds leaves and stems. Plants use the most of it during the vegetative stage.
• Phosphorus supports root growth and flower formation.
• Potassium helps the plant manage water and fill out its flowers.

Calcium, magnesium and sulphur come next. Plants need less of them, but a shortage still shows. Calcium and magnesium run low most often in coco, or when you water with soft or reverse osmosis water. That is why many coco growers add a Cal-Mag supplement.

Iron, manganese, zinc, boron and copper are trace elements. Plants need only tiny amounts, and a complete fertilizer already contains them.

Feed for the stage, not the calendar

Seedlings

For the first week or two a seedling lives on what is stored in the seed and what is in the soil. Pre-fertilized potting soil is enough. Feeding too early is one of the easiest ways to burn young roots.

Vegetative stage

Use a grow fertilizer with more nitrogen than phosphorus. Start at half the dose on the label. Raise it only when the plant asks for more, for example when the lower leaves start to turn pale.

Flowering

Switch to a bloom fertilizer once the first white pistils appear. It has less nitrogen and more phosphorus and potassium. Too much nitrogen late in flowering keeps the leaves dark green but does nothing for the buds.

Autoflowers

Autoflowers stay small and move through each stage quickly. Most growers give them a lighter dose than photoperiod plants.

pH matters as much as the bottle

Roots can only take up nutrients within a certain pH range. Outside that range the nutrients stay locked in the soil, however much you add. A rough guide:

• Soil: 6.0 to 7.0
• Coco and hydro: 5.5 to 6.5

Measure the pH after you have mixed the fertilizer into the water. The nutrients themselves shift the pH, so a reading taken before mixing tells you little.

Measure instead of guessing

An EC or PPM meter shows how strong your nutrient mix is. It doesn’t cost much and takes most of the guesswork out of feeding. Every brand gives its own target values, so follow the chart that comes with your fertilizer and write down what you give.

Signs that you are giving too much:

• brown, burnt-looking leaf tips
• leaves that turn very dark green and curl down like a claw

If you see this, give plain pH-adjusted water for a few days before you feed again. Lower leaves that yellow from the bottom up usually point the other way: too little nitrogen.

Mineral or organic?

Mineral fertilizers act fast and are easy to dose, which makes mistakes easy to correct. Organic feeds work through the life in the soil. They act more slowly and are more forgiving. Both grow good plants. If you want to try something from your own kitchen, see our article on natural homemade fertilizers.

Picking a replacement for Van Gogh’s

When you choose a new brand, check for:

• separate grow and bloom products
• a feeding chart per week or per stage
• the NPK numbers printed clearly on the label
• a brand your local grow shop stocks, so you can buy the same bottle again

Start with the base nutrients. Boosters, enzymes and additives are extras. Add them once the basics are going well, not before.