Borax

Borax

Borax (sodium borate) is a water soluble boron salt, 11.3% boron, used in very small amounts to correct boron deficiency from a soil test. It suits advanced growers and certified organic growers working to a soil prescription.

At a glance

• Type: trace element salt (soluble powder)
• Analysis: boron 11.3% by weight, sodium 12.1% (sodium tetraborate decahydrate)
• Use for: correcting boron deficiency before flowering and fruit set
• Rate: no rate is given on the current page; dissolve in water and spray for even distribution

What it is

Borax is sodium tetraborate decahydrate (Na₂B₄O₇.10H₂O), a salt of boric acid. It dissolves in water, so it is applied as a spray or through irrigation.

What it does

• Boron is needed for cell wall formation, pollen viability and seed and fruit set.
• Deficiency shows as dead growing points, hollow or corky stems and poor fruit set.
• Growers apply boron before flowering to support flowering and fruit set.

Analysis

• Boron (B) 11.3% by weight (sodium tetraborate decahydrate, Na₂B₄O₇.10H₂O)
• Sodium (Na) 12.1% by weight

How to use

• Dissolve in water and spray for even distribution.
• Foliar: 200 to 400 g per 100 L of water (0.2 to 0.4%), two or more sprays at critical growth stages; use the lower rate on sensitive crops.
• Soil: apply the rate your soil test or prescription calls for, watered in evenly.
• Boron has a narrow margin between enough and too much: apply from a soil or leaf test and do not exceed the rate.

Learn more in fifteen seconds

• Boron: what it does
• More isn't better

Handling and storage

• Wear a mask to avoid inhaling particles and open in a well ventilated area.
• Wear gloves and eye protection, and wash hands after use.
• Once opened, keep sealed and dry.