Druid Nutrients - Uruz

A single mineral component: calcium nitrate in powder form, with 26.5% calcium oxide and 15.5% nitrogen. Intended as a calcium supplement for substrates that supply little calcium. 500 grams.

This is a calcium product, even though the nitrogen catches the eye

The bag says CALCIUM TRUST, and Druid describe it as a bioactive calcium supplement for low calcium substrates. That is the reason to buy it.

The 15.5% nitrogen is strikingly high and therefore misleading. In calcium nitrate the nitrate group is the counter-ion: it is the form in which the calcium is delivered, not a separate nitrogen dose you set deliberately.

Buy Uruz to add nitrogen and you have bought a calcium supplement. Do count the nitrogen in your overall schedule though, because it arrives whether you want it or not: at 60 grams in 100 litres you are adding over 9 grams of nitrogen.

The analysis on the bag

• Calcium oxide (CaO): 26.5%, roughly 19% calcium.
• Total nitrogen: 15.5%.
• Of which nitrate nitrogen 14.4% and ammoniacal nitrogen 1.1%.

So it is almost entirely nitrate nitrogen with a small ammoniacal fraction. For anyone steering on the ratio between the two: that share is small enough not to shift your pH appreciably.

Dosage and preparation

50 to 70 grams per 100 litres of water.

That is a different unit from the one you are used to on this shelf, where nearly everything is quoted in millilitres per litre. It works out at 0.5 to 0.7 grams per litre: for a 10 litre watering can, 5 to 7 grams.

The preparation is on the bag and it is short:

• Stir for five minutes. The powder dissolves readily in water, but give it that time.
• Then feed it to the plants.

Five minutes sounds long for a powder that dissolves easily. The point is that incompletely dissolved material stays suspended in a reservoir and settles out later, which becomes a problem with fine drippers.

What it is intended for

Druid name hydroponic, aeroponic and ultrasonic mist systems on the label, for the growth and flowering phases of short cycle plants.

The indication is a substrate that supplies little calcium. That is the situation where this product makes sense: recirculating systems on reverse osmosis or soft water, where the calcium comes neither from the medium nor from the tap. If you work on a lime-rich potting compost or with hard tap water, chances are you do not need it.

Dissolve it separately and do not mix it neat with other concentrated fertilisers: calcium and phosphate or sulphate precipitate together in concentrated form.

Storage

Keep it in its original packaging and close it tightly after use. It is a salt and it attracts moisture; an open bag cakes. Store out of reach of children.

Technical Specifications:

• Type: single mineral component, powder
• Manufacturer: Druid Nutrients, Best
• Compound: calcium nitrate
• Calcium: 26.5% as CaO, roughly 19% calcium
• Nitrogen: 15.5% total, of which 14.4% nitrate and 1.1% ammoniacal
• Dosage: 50 to 70 grams per 100 litres of water
• Preparation: stir for five minutes, then apply
• Systems: hydroponic, aeroponic and ultrasonic mist systems
• Indication: substrates that supply little calcium
• Packaging: 500 grams
• Storage: original packaging, tightly closed, dry

Frequently asked questions

How much do I use?
50 to 70 grams per 100 litres of water, that is 0.5 to 0.7 grams per litre. Stir for five minutes before feeding.

Is this a nitrogen fertiliser?
No. The 15.5% nitrogen is the counter-ion of the calcium. The product is meant as a calcium supplement.

Do I need it?
Only if your substrate or water supplies little calcium, for instance on reverse osmosis or soft water in a recirculating system.

Can I throw it in with my other feed?
Dissolve it separately and do not mix it neat with other concentrates: calcium precipitates together with phosphate and sulphate.

Why is my bag caking?
It is a salt that attracts moisture. Close the original packaging tightly after use and store it dry.