There’s an easy and quick way to prepare liquid fertilizer. All it takes is to dissolve urea (46-0-0) in water.

This dilute solution can be immediately used for soil drench and spray application to supplement nitrogen to plants in need of the nutrient or to ensure its availability.

**1% urea solution can be prepared just before application**

The basic procedure that we follow is based on the long-established fact that 1% urea solution can be sprayed or used to water many plants including the leafy vegetable pechay (*Brassica* sp.).

As for maintenance fertilizer for potted seedlings in the nursery, we do the watering once a week to once every two weeks.

*But first, the theoretical basis.*

**Here’s How to Prepare a 1% w/v Urea Liquid Fertilizer**

**Materials**:

- Urea granules or 46-0-0
- Water
- Weighing scale
- Container to hold water such as a plastic pail or basin
- 1-li water dispenser
- Water-resistant marker

**Procedure:**

**1. Decide** on the volume of liquid fertilizer to prepare, for example, 10 liters.

**2. Convert** the volume of liquid fertilizer to unit of weight (from ml to gram) by using the following 1:1 volume-to-weight equivalent of water at normal atmospheric pressure: 1 ml = 1 cc = 1 g or 1 li = 1 kg.

Then calculate the weight of urea (46-0-0) granules to dissolve with the following formula:

**Wu = Cu x Wf**

where:

**Wu** = weight of urea to be dissolved (in gram)**Cu** = desired concentration of urea in the liquid fertilizer (in decimal, i.e., 1% = 1/100 = 0.01)**Wf** = weight of liquid fertilizer to be prepared (in gram, i.e., 10 li = 10 li x 1,000 ml/li = 10,000 ml = 10,000 g).

**Solution:**

**Formula: Wu = Cu x Wf**

**Wu** = 0.01 x 10,000 g=** 100 g**

**Note:** The unit of measurement for the weight of liquid fertilizer to be prepared (**Wf**) may be in kilogram (kg).

If so, **Wu** will also be in kg.

To convert kg to gram (g), multiply by 1000 since 1 kg = 1,000 g. Therefore, 0.1 kg is equivalent to 100 g. That is, 0.1 kg x 1,000 g/kg = 100 g.

Conversely, gram can be converted to kilogram by dividing it by 1,000. Therefore, 100 g is equivalent to 0.1 kg. That is, 100 g ÷ 1000 g/kg = 0.1 kg.

**3. Pour 10 liters** of water into a container (e.g. plastic basin or pail).

Allow the water to settle and mark the 10-li level. Then remove water in excess of 100 ml from the container.

**4. Weigh 100 grams** of urea and add to the water in the container. Stir by hand or any stirrer until completely dissolved.

**5. Allow the liquid solution** to settle then slowly add more water up to the 10-li mark.

**Note:**

The above steps provide for the production of a 1% w/v urea liquid fertilizer.

It means that the fertilizer solution has a 1% concentration of urea, w/v basis. “w/v” means “weight over volume.” That is,

**Urea Concentration** = (**Wu** ÷ **Vf**) x 100 = (100 g/10,000 ml) x 100 = **1%**,

where 100 g is the weight of urea and 10,000 ml is the total volume of the liquid fertilizer.

The multiplier “100” without any unit of measurement is a constant in converting fraction (w/v) to percentage (%).

As an alternative, the weighed urea (100 g) may be dissolved in water that is poured into a container placed on a weighing scale.

After the urea is completely dissolved, water is added until the weight of the solution reaches the 10-kg mark.

This will produce 1% w/w urea solution.

Precision in producing a 1% w/w concentration of the liquid fertilizer will depend largely on the accuracy of the weighing scale.

**The Volume of Liquid Water Used as Solvent**

The amount of water that was used to dissolve 100 grams of urea to produce 10 liters of liquid fertilizer with 1% concentration of the solute can be derived.

Use the following formula:

**Vw = Vf – Vu**

where:

**Vw** = volume of water used as solvent (ml)**Vf** = volume of liquid fertilizer prepared (ml)**Vu** = volume of urea dissolved in water (ml, i.e., 100 ml = 100 g).

**Solution:**

**Vw** = 10,000 ml – 100 ml = **9,900 ml**

Click here to read more about the density of water

**Practical Application**

For landscape and house plants, as well as for potted seedlings in the nursery, there is no necessity for technical accuracy.

For convenience, it is sufficient to dissolve 1 level tablespoon of urea granules in 1 liter of water or multiples thereof.

This is based on the approximation that 1 tablespoon of water is equal to 10 ml or 10 grams.

As a measuring tool for the solvent in excess of 1 liter, water is poured from a **1-liter bottle** into a dipper and the top level is marked.

One (1) heaping tablespoon of urea dissolved in water dispensed from a 1.5-liter softdrink bottle will have approximately the same dilution rate.

The above procedures allow the production of liquid fertilizer in small quantities without using a weighing scale.

Otherwise, if the amount of urea to be dissolved is so small, for example, 10 grams, it will be necessary to produce a digital balance or one that is capable of detecting such weight.

Hi Ben. Thanks for this info. What would be the recommended spray area of a lawn with either 1tbs x litre water. What would be consideration to use 2tbs x 1litre water. Regards.

Being a practical farmer it has been very helpful. Please could you do same kind of calculation to produce 1% solution of 20 20 30 Haifa bonus NPK that can be used to water plants directly since the quantities are not the same..