Foliar Urea Spray & Urea, Tanks & Dose
Feeds tillering
Enter spray volume and concentration to get the total urea, number of tanks and urea per tank— for a safe, even foliar nitrogen boost without leaf scorch.
Foliar urea spray
Next: dissolve 4 kg urea in 200 L — about 300 g per 15 L knapsack tank across 14 tanks.
Caution: keep biuret <2% on standing crops and avoid spraying in hot midday sun to prevent leaf scorch. Best applied at tillering / flowering for a quick nitrogen boost. Use a fresh, fully dissolved solution.
Foliar urea spray — key facts
- Urea needed
- spray volume × concentration%
- Best stages
- tillering, flowering, grain-fill
- Max strength
- ≤ 2% on standing crops
- 2% spray
- 2 kg urea per 100 L
- Grade
- use low-biuret urea
- Spray when
- cool hours, no wind
- Avoid
- midday heat & stressed crops
- Privacy
- Runs in your browser; nothing uploaded
A fast nitrogen top-up — without burning the crop
When a crop needs nitrogen now — at tillering, flowering or grain-fill, or to rescue a visibly deficient stand — a foliar urea spray delivers it straight to the leaves, far faster than soil-applied urea can work through the roots. The catch is concentration: get it right and the crop greens up; go too strong, spray in the heat, or use high-biuret urea and you scorch the very leaves you're feeding.
This tool takes your spray volume and target concentration and returns the total urea, number of tanks and urea to add per tank, so every load mixes to a safe, even strength. Keep it at or below 2% on standing crops, use low-biuret urea, and spray in the cool hours. Pair it with the Nano Urea, Micronutrient Spray and Fertigation tools for a complete in-season feeding plan.
Mix it right
Exact urea per tank for a safe strength.
Avoid leaf scorch
Stay at or below 2% on standing crops.
Boost at key stages
Feed nitrogen at tillering, flowering, grain-fill.
Pre-measure tanks
Know the dose for every tank load.
Frequently Asked Questions
What is a foliar urea spray?+
A foliar urea spray dissolves urea in water and applies it to the leaves, where the nitrogen is taken up quickly. It's used to give a fast nitrogen boost at key growth stages — tillering, flowering and grain-fill — to correct a deficiency or top up the crop without waiting for soil-applied fertiliser to work through the roots.
How is the urea dose calculated?+
Total urea = spray volume × concentration. For a 2% spray that's 2 kg of urea in every 100 litres of water. This tool takes your total spray volume and target concentration, returns the total urea needed, then splits it across your tank size to give the urea to add per tank and the number of tanks.
What concentration of urea is safe?+
Keep the concentration at or below about 2% on standing crops. Stronger solutions risk scorching the leaves, especially in hot, bright conditions. Cereals tolerate up to around 2%, while tender leaves and some horticultural crops need lower strengths — always test on a few plants if unsure.
Why use low-biuret urea?+
Biuret is a contaminant formed when urea is overheated during manufacture, and it's toxic to leaves at the concentrations used in foliar sprays. Low-biuret urea (typically under about 0.25% biuret) avoids leaf damage, so it's the grade recommended for foliar feeding rather than ordinary soil-grade urea.
When and how should I spray?+
Spray in the cool hours of early morning or late evening when the stomata are open and evaporation is slow, avoiding the heat of midday and windy or pre-rain conditions. Wet the foliage evenly to the point of run-off, and don't spray a crop that's already stressed by drought.
How many tanks will I need?+
The tool divides your total spray volume by your sprayer tank size to give the number of tank loads and the urea to weigh into each tank. That lets you pre-measure the urea per tank so every load is at the right concentration, instead of guessing and risking a scorching dose in one tank.
When is a foliar spray better than soil urea?+
Foliar feeding shines for a quick correction or a targeted top-up at a critical stage — for example nitrogen at grain-fill to lift protein, or rescuing a visibly deficient crop. For the bulk of a crop's nitrogen, soil-applied urea is more economical; foliar sprays supplement rather than replace it.
Can I add other inputs to the tank?+
Urea is often tank-mixed with micronutrients or other foliar inputs, but always check compatibility first, as some combinations react or settle out. Do a jar test, keep the total salt load modest to avoid scorch, and follow label guidance — when in doubt, spray urea on its own.
Are the figures precise?+
The urea, tanks and dose per tank are exact for the volume and concentration you enter. Real results depend on coverage, leaf condition, weather and timing. Use the recommended concentration, spray in cool hours with low-biuret urea, and treat foliar feeding as a precise top-up rather than the crop's whole nitrogen supply.