How Long Should Fertilizer Be Down Before It Rains?

how long should fertilizer be down before it rains

A common question we get asked is “how long should fertilizer be down before it rains?” Now, there’s no easy answer to this question because it depends on various factors.

Firstly, let’s talk about why you need to fertilize your lawn.

Why Fertilize Your Lawn?

All plants need nutrients to grow, just as we need food to sustain our bodies. Most lawns require a fertilizer which is high in nitrogen. This is because nitrogen stimulates green plant growth. So, when selecting a suitable fertilizer, make sure you check the N-P-K ratio. A good lawn fertilizer should have a much higher ratio of N (nitrogen) than P (Phosphorous) or K (potassium).

A good way to tell that your lawn needs fertilizing is if it’s not growing quickly or it doesn’t look green and lush. Especially, in the optimum growing season.

Common Ways To Fertilize Your Lawn

fertilizing your lawn

There are a number of ways to apply fertilizer to your lawn, depending on how much grass you have. A broadcast or rotary spreader can make your job easier if you have a large area that you need to feed.

On the other hand, if you have a standard suburban lawn, you could consider investing in a drop spreader. This will allow you to distribute the fertilizer evenly across your lawn.

For smaller lawn areas, try using a handheld broadcast spreader and walk over your lawn slowly, spreading the fertilizer as you go. Try to overlap a little so you don’t miss any patches of grass. Nothing spoils the look of a lush green lawn more than a few patches of yellow grass.

You can even get a handheld spreader which is battery powered so all you have to do is walk across your lawn and the spreader does all the work.

All Fertilizers Need To Be Watered In

watering in fertilizer

Having your fertilizer just sit on top of the grass is not going to give you a lush thick lawn. The fertilizer needs to move down into the soil to allow the roots to take up the nutrients.

In fact, granular fertilizers need water to activate them so that nutrients are released gradually.

So therein lies the question as to “how long should fertilizer be down before it rains?”.

This really depends on how much rain you’re expecting. If the forecast is telling you that you’re going to get less than ½ inch of rain, then by all means, go ahead and fertilize the day before.

In this scenario you won’t have to water in your fertilizer after applying it.

Avoid Fertilizing Before Heavy Rain Is Expected

If the forecast is telling you that you’re going to get heavy or torrential rain, then avoid fertilizing if you can. The reason for this is that too much rain will wash away the fertilizer and it will end up in the storm drains.

There’s also more likelihood of this happening if you’re on a slope, your soil is compacted or you have extra thick turf.

Not only is this a complete waste of your money but it’s also very bad for the environment. The fertilizer will eventually end up in local waterways such as creeks and rivers and will pollute the water.

If you simply must fertilize before a heavy downpour is expected, then water in your fertilizer by hand or using a sprinkler, to ensure that it moves down into the soil.

Fertilizing After A Heavy Rainfall Is Also A Good Idea

Ensuring that soil beneath your grass is damp and not dry is a good practice to follow when fertilizing. Therefore, you can apply your fertilizer immediately after heavy rain but ensure that the blades of grass are completely dry.

The moisture in the soil will help to draw the fertilizer down and you’ll only need to give your lawn a light sprinkle after applying it. Just make sure that you’ve given it enough of a sprinkle so that no fertilizer remains on the grass itself. This is because when the sun comes out, any fertilizer left on the grass can easily burn it.

What About If You’re Applying A 2-in1 Fertilizer And Weedkiller

If your fertilizer is a 2-in-1 which includes a weedkiller, then you really need to wait at least 24 hours before applying any water to your lawn. This will give the herbicide time to be absorbed by the weeds.

Avoid Fertilizing During Drought Conditions

As mentioned before, fertilizer needs water to activate it and allow the roots to access the nutrients. Therefore, it’s unwise to fertilize if you’re experiencing drought conditions. Doing so will only serve to burn your grass rather than produce a lush, green lawn.

Why Not Consider Grasscycling


Grasscycling is a trendy term which means to leave your clippings on the lawn instead of adding them to your compost bin or just throwing them away. In fact, it’s an old practice which is once again gaining popularity.

Over time, these clippings will break down into the soil and feed your lawn with the nutrients they release. This could provide your lawn with around twenty-five percent of the necessary nutrients every year.

You can either purchase a mulching mower to help with this or replace your current blade with a mulching blade. And, of course, leave the catcher off the mower. Or, if you also want some additional exercise, you can always use a person-powered push mower. This can be most effective if you mow often and only have a small lawn area.

Compost Is Not Just For Vegetable Gardens


If you make your own compost for your vegetable garden, why not consider applying some of it to your lawn as well.

This is especially effective if you aerate your lawn beforehand. The nitrogen in the compost acts like a slow release fertilizer adding nutrients to the roots of the grass over time. This also solves the problem of heavy nitrogen leaking into the groundwater.

In addition, the compost will help to improve the soil beneath your grass and make it less prone to compaction. After applying the compost, gently work it into the grass with a rake or a stiff broom.

Frequently Asked Questions:

How long does it take for granular fertilizer to dissolve?

Granular fertilizer should ideally break down within 2 weeks.

Can I mix granular fertilizer with water?

The simple answer is yes, but instead of then applying the granules, you would strain off any solids that are left after soaking the granules for around 24 hours. Then you would apply the remaining liquid instead.

Which is better, liquid or granular fertilizer?

Generally speaking, liquid fertilizer is better because it’s more readily available to the roots of the plants and of course, doesn’t have to be watered in.

So, How Long Should Fertilizer Be Down Before It Rains?

Hopefully, we’ve now answered that question. In short, you can fertilize the day before light, steady rain is expected. However, if you’re expecting heavy rain, either avoid fertilizing or water in the fertilizer before any heavy downpour.

Leave a Comment

Your email address will not be published. Required fields are marked *