Atami - Premium Plant Powder Soil

A chelated bio-mineral base nutrient in powder form for growing in soil, in a 1 kg bag. You dose 0.5 to 1 gram per litre of water, and you read the result on your EC meter rather than off a measuring jug.

Powder is dosed on EC, not on millilitres

This is the difference that makes switching from liquid to powder awkward, and it is rarely explained anywhere. With a liquid feed you work to a fixed ratio: so many millilitres per litre, done. With this powder you work towards an EC value.

Atami give a usable figure for that: every 0.1 gram of Premium Plant Powder raises the EC of a litre of nutrient solution by 0.09 mS/cm. That keeps the arithmetic small. Half a gram per litre lifts you about 0.45 mS/cm, a full gram about 0.9.

So you know in advance what a dose does to your tank. If your tap water already sits at 0.4 mS/cm and you want 1.3, you need roughly 1 gram per litre. If you want 0.9, half a gram is enough. You work back from your target to the weight, not the other way round.

It is also why a kitchen scale is worth more here than a measuring jug. Over ten litres of water the difference between 5 and 10 grams is the difference between a light feed and a full one, and you will not judge that reliably with a scoop.

Soil already buffers, so you start low

This version is made for potting compost and peat mixes, and that medium does something rockwool and coco do not: it holds nutrients and releases them gradually.

Two things follow in practice. Pre-fertilised potting compost already supplies part of what the plant needs in the first weeks, so there you start at the bottom of the range. And because soil holds on to what you give it, anything you overdose does not count once but accumulates in the pot.

The EC you measure in your irrigation water is therefore not the same as the EC around the roots when you grow in soil. If you grow in soil and you are unsure, you are better off skipping a feed than adding one.

What is in it

Atami describe the range as chelated mineral plant nutrients in powder form. Chelated means the metals sit in a wrapper that keeps them available for uptake, including when the pH is not perfect. Alongside calcium the powder contains magnesium, which Atami call the key element in photosynthesis.

It is a one-component feed for the whole cycle: there is no second bag and no separate bloom version. Add it from the growth phase onwards, daily with the irrigation water. Atami recommend combining it with their bio-stimulators for the best result.

Why a powder

A kilo of powder makes a thousand litres of nutrient solution at 1 gram per litre. That same volume in liquid form is a considerable number of jerrycans, with the water already in them. Powder is therefore cheaper to ship and to store, and that is exactly why Atami make it.

The bag is light tight. Store it at room temperature in the dark and keep it closed: powder draws moisture and clumps from it.

Technical Specifications:

• Type: chelated bio-mineral one-component nutrient in powder form
• Manufacturer: Atami
• Substrate: potting compost, soil and peat mixes
• Contents: 1 kg
• Dosage: 0.5 to 1 gram per litre of water
• EC: every 0.1 gram raises EC by 0.09 mS/cm per litre
• Period: from the growth phase, throughout the cycle
• Frequency: daily with the irrigation water
• Contains among others: calcium and magnesium
• Storage: closed, dark, at room temperature

Frequently asked questions

How many grams do I need?
Work back from your target. Every 0.1 gram per litre adds 0.09 mS/cm, so 0.5 gram gives roughly 0.45 and 1 gram roughly 0.9 on top of your tap water EC.

Can I use this on coco or rockwool?
No. There is a separate Coco version and a separate Hydro version, and they differ in more than the name. Pick the one that matches your medium.

Do I need a separate bloom nutrient?
No, this is a one-component feed for the whole cycle. Atami do recommend using stimulators alongside it.

My powder has clumped.
That is moisture. Keep the bag closed, dark and at room temperature. Clumping says nothing about how it works, but it does make accurate weighing harder.

Why is there no NPK on this page?
Because Atami publish none for this range. What circulates in the trade does not cover all three substrate versions, and we would rather leave it off than publish one of three.