Can You Fertilize Wet Grass? When it’s Ok and When it’s Not

Most fertilizers need watering into the grass.

So it makes sense to fertilize when the grass is already wet, right? Or better yet, in the rain?

Unfortunately not.

Fertilizing really wet grass, or when it’s raining, is rarely a good idea. There may be some instances when you can get away with it. But in general, it’s best to avoid fertilizing your lawn when it’s wet.

I’m going to answer the question, can you fertilize wet grass? I’ll explain when it’s ok, and when it’s not.

Keep reading to decide which category your lawn fits into.

What Happens if You Apply Fertilizer to Wet Grass?

The more detailed answer to this question is that it depends on how wet your grass is, and what kind of fertilizer you are using.

Different fertilizer types will cope with varying amounts of moisture on your lawn.

Let’s go through each fertilizer type and how wet your lawn can be for application.

And if you’re wondering whether the fertilizer you already have is still good to use, have a read of my article on whether fertilizer goes bad.

Liquid

Liquid fertilizers usually come in a concentrated form and need diluting before application. Consequently, it’s easy to think that you could save yourself some work by applying the fertilizer when the grass is wet.

However, this is risky.

If your lawn is so wet that there are puddles, or your footprints sink into the soil when you walk, using liquid fertilizer is a bad idea, period.

The fertilizer will be diluted to the point that it’s not useful, and will likely be washed away, contributing to pollution.

Since it will be hard to know how much of the fertilizer actually reached the grass, you may end up applying more, and over-applying as a result.

The other risk is that since lawns are usually naturally a little uneven, it follows that the amount of water in your lawn if it’s very wet will also be uneven. This means it’s likely that the fertilizer would end up being too diluted in some areas, while ending up too concentrated in others.

The symptoms of too much fertilizer include yellowing leaves from nitrogen burn. This means it could be hard to know which areas have received too much, or are suffering for other reasons.

It’s safest to avoid applying liquid fertilizer when your lawn is wet, and wait until it has dried instead.

Granular

Granular fertilizer is safer to apply in wet conditions than liquid fertilizer. This is because it isn’t washed away as easily, and isn’t as easily diluted.

However, as already mentioned, if your lawn is really sodden, it’s not a good idea to apply any fertilizer, even granular.

The only time it’s ok to apply granular fertilizer to a wet lawn is when there has just been some light rain, your lawn is damp but the soil isn’t saturated, and there is no further rain forecast for several days.

If you’re interested in learning more about the difference between liquid and granular fertilizer, I have an article on exactly that that you should check out.

Foliar

Unfortunately, it is never ok to apply foliar fertilizer to wet grass, no matter how wet.

Foliar fertilizer needs to make contact with the grass blades, a.k.a. foliage. If the grass is even a little damp, foliar fertilizer will not be able to stick and do its job.

Instead, it’s essential to wait until your lawn is dry to apply foliar fertilizer.

Organic

Organic fertilizers are generally more forgiving than synthetic fertilizers when it comes to wet conditions, especially if they are in the form of solid materials like compost.

But to be safe, consider the rules for organic fertilizer to be the same as granular when it comes to a wet lawn. If you leave squelchy footprints behind on your lawn when you walk, it’s too wet.

If your lawn is just a little damp, it’s ok to fertilize with organic fertilizer, provided there is no heavy rain forecast.

Controlled/Slow-Release

Controlled-release or slow-release fertilizers generally come in granular form with coatings which slow how quickly they are broken down by light and water. Slow-release liquid fertilizers do exist but they are less common.

Slow-release granular fertilizers can be applied if the lawn is wet but the soil is not saturated.

Quick-Release

Quick-release fertilizers almost always come in liquid form. It’s never a good idea to apply quick-release fertilizers when the lawn is wet. The chance of the fertilizer becoming too diluted and being washed away is too high.

It’s also likely that your lawn would end up unevenly fertilized, with some parts of the lawn receiving none, and some parts too much.

Since too much fertilizer can seriously harm the health of your lawn, this is something you definitely want to avoid.

Reasons to Avoid Applying Fertilizer When Your Lawn is Wet

We’ve gone over the different kinds of fertilizers and whether it’s ok to apply them when the grass is wet.

But if you just want to know why it’s risky to apply fertilizer to wet grass, regardless of the type of fertilizer, here are the reasons:

Uneven Fertilization

No matter how much work you put into making your lawn as uniform and even as possible, nature rarely complies. All lawns, even the most perfectly manicured, are inherently uneven to some degree.

If there has been heavy rain, there will be areas that are wetter than others. There will be areas that are more prone to standing water, and areas that tend to avoid this.

This is bad news when it comes to fertilizing. Fertilizers of any kind will end up being more diluted in wetter areas, and may even end up flowing into the less wet areas, becoming overly concentrated.

In general, fertilizing a very wet lawn is likely going to end up with uneven results.

If your lawn appears persistently wet, it may also need aerating. You may have compacted soil, or soil that is heavy with clay. Aeration will increase the drainage of the soil and help it to dry out more quickly after heavy rain.

If you’re new to aerating, I have a complete guide to aerating that will help you, and also more info on how often to aerate, and a guide to different types of aerators too.

Dilution

Even if your lawn is super even, if it is very wet, the fertilizer you apply is going to end up too diluted. This means that your grass won’t benefit from it, and you’ll likely need another application.

Nitrogen Burn

The other extreme of dilution occurs from too much fertilizer. Nitrogen burn occurs when more nitrogen than is useful to the plant is applied. This could easily happen if you think that your first application of fertilizer was unsuccessful, and so you apply more.

If you’re not sure whether your first application ended up being too diluted, don’t apply again. It is far more damaging to your grass to apply too much fertilizer than not enough.

Water Pollution

Applying fertilizer to wet grass increases the risk of run-off. This is when excess nutrients are washed into the surrounding environment, causing pollution to water bodies like streams and lakes.

You might think that nutrients like nitrogen, phosphorus and potassium don’t count as pollution, but they most certainly do. Especially when they have come from synthetic fertilizers rather than natural sources.

Too much nitrogen, in particular, causes toxic algal blooms. The byproduct of nitrogen, nitrates, also lowers the pH of water bodies, causing them to become more acidic and unlivable for many species of plants, fish and insects.

Wasted Time and Money

Last but not least, applying fertilizer to overly wet grass wastes your time and money.

If you’re really struggling to find an opportunity to fertilizer your lawn when everything is dry enough, you’re better off not bothering at all.

Other Considerations

Does Your Yard Need Fertilizer?

Assuming it’s dry enough, before you waste time and money fertilizing your lawn, it’s worth deciding whether it actually needs fertilizing at all.

Contrary to popular opinion, regular fertilizing shouldn’t be necessary if you have healthy soil. In fact, routine fertilizing with synthetic fertilizers can set you up for an unhealthy dependence on these chemicals.

Repeated use of synthetic fertilizers actually degrades soil health, making it harder for soil to hold on to water and nutrients.

Synthetic fertilizers also increase the acidity of soil over time, resulting in the need for more soil amendments to make the soil more alkaline. If your soil has become acidic, you may notice that your grass isn’t looking very happy, and wrongly think that more fertilizer is the answer.

Do a soil test, find out if your soil is lacking important nutrients, and fertilize on an as-needed basis, rather than routinely.

I have another article on how often to fertilize your garden that might also be helpful.

Organic versus Synthetic Fertilizer

As mentioned above, since synthetic fertilizers degrade soil health over time and make your lawn more dependent on continued applications, it’s worth considering the alternatives.

Organic fertilizers are made using raw materials such as sea weed, fish meal and animal manure. The benefits of using organic fertilizers are numerous but the main bonus is that you get increased soil health over time.

Organic fertilizers contain many more micronutrients aside from the classic NPK formulations. But the best part is that these nutrients are in their natural form, making them supportive of the essential microbes that you need for good soil health.

Happy microbes mean happy soil, which means happy plants.

Lastly, organic fertilizers are also slow-releasing, meaning you don’t run the risk of nitrogen burn.

Avoid Weed and Feed Products

Weed and feed products are bad for you, your pets, the environment, and arguably your lawn too.

They use quick-release fertilizer which can result in nitrogen burn, and/or be washed away to pollute the surrounding environment. But the really bad part is in the ‘weed’ component.

These herbicides are harmful to surrounding trees, shrubs and other plants, not to mention humans and pets. They also persist in the soil and bio-accumulate, making the soil toxic for all forms of life.

This is scary enough, but in weed and feed products, rather than being applied directly to the weeds in question, they are applied broad scale over the entire lawn, resulting in a far greater amount being used than was ever necessary.

Most lawns only contain around 5-10% weed species, making complete coverage unnecessary.

Furthermore, there are natural ways to manage lawn weeds that are far preferable. Regular mowing is enough to keep things like dandelions under control. Overseeding is also an effective way to increase the density of your lawn so that it can naturally out-compete weeds.

Keep Your Lawn Healthy Naturally

On a similar note, did you know that there are other things you can do to avoid having to fertilize?

Practices such as leaving some grass clippings on your lawn to break down naturally, and deliberately including clover in your lawn, can mean that your lawn is healthy enough to not require fertilizing. Great, right?

It’s also worth making sure that you aren’t cutting your grass too short. Many people actually mow too short, thinking that a tidy lawn is a short lawn. In actual fact, mowing too short is not helpful for grass health, as you end up removing the part of the grass blade that converts sunlight into food and energy.

A lawn that is too short is going to look like it’s nutrient depleted, and it is, but not because it needs fertilizing – it just needs to be long enough to adequately feed itself.

Brush up on your mowing height knowledge to promote optimal lawn health and avoid fertilizing unnecessarily.

FAQs

Can you fertilize when the ground is wet?

If the ground isn’t so wet that there is standing water, or the soil deforms when you walk on the lawn, then it’s ok to fertilize with granular fertilizer.

Can you fertilize grass in the rain?

It’s safest to avoid fertilizing grass in the rain. Unless you are sure that the rain is only going to be a light shower and not continue on for multiple days.

The risk with fertilizing in the rain is that the rain will dilute and wash away the fertilizer that you’ve applied, making it ineffective, and polluting to local water bodies.

What’s the best time to fertilize your lawn?

The best time of year to fertilize your lawn is early spring for cool season grasses. The best time of day to fertilize your lawn is in the evening, when the sun is weak.

Is slow release fertilizer better than liquid?

This depends on the state of your lawn and whether it is desperate need of a quick fix. If the answer to that question is no, then slow release is the better option.

Summary

So, should you fertilize a wet lawn?

Hopefully, now you’re feeling confident that you understand when it’s ok to fertilize a wet lawn.

In summary, if the lawn is so wet that is standing water or the soil is sodden, don’t fertilize with any fertilizer, period.

If your grass is damp but the soil isn’t, it’s fine. Go nuts. However, you’re safer using granular forms rather than liquid.

Did this article answer all of your questions? If you have any more, feel free to ask them in the comments below!