Urea In DEF Fluid: Can DEF Be Used As Fertilizer? (Guide)

There may be a second duty for DEF fluid. If you thought that DEF fluid was only to be used in your diesel truck, then you may want to rethink that thought. There is a possibility that it can be used as a fertilizer as DEF diesel fluid is made from the same ingredients as Urea fertilizer.

There are both supporters and naysayers to this use option. Many people think it is a great idea but the ones that do not recommend this option say the NPK ratio is too low. The granular is set at 46-0-0 while DEF’s ratio is 15-0-0.

To learn more about this topic, just continue to read our article. It has the information you want to know about so you can decide if you want to use any extra DEF on your lawn to help it grow better.

Can DEF Fluid Be Used as Fertilizer?


We checked a lawn care forum and no one there said anything about it being harmful to your law or that you should not use it. The only people that seemed to not like it based their objection on the nitrogen levels in the Urea in the DEF and in the granular sacks.

They say the former is too low of a ratio to be of any real good. However, no one else made that same objection. For those people who do not have access to farm supplies, this may be an option although the cost may not be so encouraging.

It has been said that you need to use 31 gallons of DEF to equal one 50-pound bag do granular Urea. The cost difference between the two is about $70 more for the DEF. You would have to figure out how much you would need for your size of lawn and then see if the cost is worth the convenience.

There needs to be a lot of comparison shopping when you are making this decision to see if you are getting the right amount of nitrogen with the amount of DEF you want to use.

Using DEF as Lawn Fertilizer


This is a possibility but there are two main concerns. The first is that the DEF has a very low nitrogen content. You would have to do a lot of math to figure out if the amount of DEF fluid you have on hand will provide your lawn, etc., with enough nitrogen to grow healthy.

Keep in mind that if you are organic gardening, etc., DEF is a synthetic product and it may not be good for your gardening efforts. Most people that have discussed this option have stated that you need a lot of DEF to get the right nitrogen level.

The second concern will be the cost. Even if you find enough DEF on sale, the word is that will not be as cheap as a 50-pound bag of Urea. You will have to weigh the costs of one against the other to see if it is practical to do or not.

DEF is made up of Urea and water and the Urea in this fluid is very refined and a lot purer than you get in a large sack of this product. You will need to weigh that aspect before you apply it to your lawn or garden.

Can You Dilute DEF Fluid?


If you are going to spread it out onto your lawn then yes, you can dilute this fluid. But if you are putting it into the tank in your engine area, then no you should not.

Car engines are built to handle a certain level of this fluid and diluting it may ruin your specs. Diluting DEF and putting it in your engine’s container would trigger the warning light that says DEF quality is low.

The best way to use Urea is to buy it in a granular form and then dilute it yourself. This is far cheaper than buying the liquid at Walmart or some other store and then spreading it out on your lawn.

The best thing to do is not to listen to those people who say you can dilute it and put it in your engine. Even those that say they have had no problem may not be telling the truth. Only dilute if you need to when spreading it out over your lawn

What Find Of Urea is Used in DEF Fluid?


Urea is a compound of Nitrogen and when it is used in different products it will turn to ammonia when heated. It is said that this is the same Urea that is found in your urine but urine is not used to make the product you put in your truck.

The Urea found in DEF is a synthetic product. It has to be made artificially due to the large amount of Urea that is required to make DEF. To make sure the DEF is safe to use, production of this product is monitored by the American Petroleum Institute.

The amount of DEF you will need to buy will depend on the quality and how many miles you get from a gallon of DEF. It is said that you will use about 2 to 3 gallons every 800 miles. Your results may vary.

If you have a 10-gallon DEF tank, you can expect to see roughly 8,000 to 10,000 miles of use before you need to refill the tank. That is a little bit better than the 800-mile consumption figure.

Some Final Words

While you can use DEF to fertilize your lawn and garden it may not be a good idea. The cost factor alone should dissuade you from going this route. If it doesn’t, then the amount of DEF you need to buy to get the right amount of nitrogen on your lawn should be.

It takes a lot of DEF to cover the same ground as granular Urea sold in those bags at the lawn care of farming supply outlets.

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