Will Rain Wash Away Your Lawn Treatment? What About Grass Seed?

Written By: Todd Thomasson

Mother Nature can be tricky.

Some days she delivers that perfect week of temperatures with perfect conditions. This would be 80-degree days with 60-degree nights and a perfect 1.5 to 2 inches of steady rainfall for those seven days.

These are not only great conditions for hanging outside in Northern Virginia, but they are also ideal conditions for growing a great lawn.

But these perfect weeks don’t always happen with weather. In fact, Mother Nature likes to keep you guessing. This, of course, is part of the job. Maybe it’s the lack of rain you receive. Or maybe you get an overabundance of rain. It’s highly likely you’ll get a rainstorm when you least expect it and wonder if Mother Nature just ruined your best effort toward maintaining your greenest, greatest grass.

You might even wonder if your lawn care professional is doing a good job or is just always blaming the weather because it seems like a convenient excuse.

When it comes to moisture at certain times of the year, you might be wondering, “Will rain wash away fertilizer?” or “Will rain wash away grass seed?”

Never fear, we have the answers for you. Let’s talk about all the impacts and benefits of rain after lawn treatments so you can better understand how showers impact your grass maintenance services.

Rain, Rain, Go Away Today … Or Not?

Rain storms, especially when they come down pretty heavy or for a few days in a row, can make you feel like they wash everything away in their path. Water is a pretty positive force, after all.

Read Our Complete Guide to The Perfect Lawn
But rain works a bit differently, depending on the lawn care application it’s following.

Here’s a look at what happens with rain after lawn treatments, and some insight into when you should worry about how rain works with various applications – everything from fertilizer to grass seed.

Will Rain Wash Away Fertilizer – Granular Applications?

If you have a Northern Virginia lawn care professional apply granular fertilizer or granular insecticide to your lawn, there’s no need to panic if it starts raining afterward.

Actually, watering in granular fertilizer and insecticide treatments is a good thing. This activates the product after application, making it more effective.

lawn care technician pouring granular fertilizer in spreader

Slow-release granular fertilizer is not easily washed away and doesn’t dissolve quickly in water. So, in this case, rain after lawn treatment is positive. And before you start thinking that you might not be watering enough after fertilization, we can ease your worries there. Generally, normal rainfall or regularly scheduled irrigation is adequate to ensure your lawn care application.

And if you’re wondering about products like grub control, then you can rest assured those will be fine as well. They usually need watered in for a couple of days to be most effective in your soil profile.

Typically, even heavier rains after lawn treatments – when it comes to granular applications – won’t negatively impact your work.

Will Rain Wash Away Fertilizer – Liquid Applications?

If you happen to receive a liquid fertilizer application versus a granular one, things will work a bit differently in this case.

lawn care technician sprays lawn with liquid fertilizer

While liquid fertilizers are water soluble and have slow-release properties similar to granular lawn care products, they hold onto the plant material and organic matter when sprayed and the plant quickly absorbs them.

But liquid products need 30 minutes of drying time before becoming rainfast. Rain that comes in that 30-minute window could wash away liquid fertilization. In this case, rain after lawn treatment immediately could mess with your work.

Rain After Lawn Treatment – Weed Control

Naturally, controlling weeds on your property is another task on your lawn care to-do list, and you might be wondering how rain might impact this treatment.

lawn care team sprays for weeds

When it comes to controlling weeds on your lawn, herbicides work very similar to fertilizers. Rain will either help or hurt a treatment based on if that treatment was liquid or granular.

A granular pre-emergent herbicide will stick to the ground and benefit from some post-treatment watering via rain or irrigation, while a liquid post-emergent herbicide requires 30 minutes of dry time for the plant to absorb it so it can do its job. In this case, rain after a lawn treatment here could wash it off.

Will Rain Wash Away Grass Seed?

Now that you are updated on what rain does to lawn care applications, maybe you’re also asking yourself, “Will rain wash away grass seed?”

In the fall, once a lawn care professional aerates and overseeds your grass, you want to saturate your lawn with water as soon as possible, keeping it evening moist.

What does saturate really mean? It depends on your soil type. If it’s heavy clay like a lot of those in Northern Virginia, it’ll take longer to saturate than a sandier soil. To reach saturation, you want to water one hour per section to get the water down 1 or 2 inches into the soil. The goal is to keep the seed moist, but not submerged in water, at all times.

lawn care technician aerates grass

When it comes to how often you have to water after seeding your lawn, here’s where you have to pay attention to the weather. If seed is drying out throughout the day, and Mother Nature isn’t delivering rainfall, then you’ll need to water a second time each day to ensure consistent moisture until your grass seeds germinate. This process takes about 10 to 14 days.

After the seed germinates, you can back off of watering to once a day for 30 minutes in each section until your lawn is established. Many people will water until germination, and then stop watering, thinking their job is done. But you want to continue your irrigating schedule so those final seeds germinate and your tender new lawn shoots have a chance to grow strong with adequate rainfall.

And the important part about watering correctly after seeding or overseeding your lawn is that it boosts your germination rate. In fact, your seed germination can increase to 90 to 95 percent, maximizing nearly all the seed you put down. If lawns fail to seed, many times the reason is due to inadequate watering. You definitely don’t want to waste valuable seed when you’re trying to thicken your lawn or fill in bare areas.

Water Can Be Your Partner in Your Lawn Care

When it comes to having a thick, green, and thriving lawn, water can certainly help you achieve your goal.

Now that you understand rain after lawn treatments, and how it impacts them, we hope you can see how water is a partner in your grass care.

Correct fertilization, as well as insect and disease prevention and control, helps keep those nasty lawn invaders at bay so your grass can do what it needs to do. And with grass seeding, water is a partner in aiding germination. Rainfall, in essence, can boost the effectiveness of these products.

Still worried about rain after lawn treatments and whether or not it helps or hurts your lawn? We understand. Lawn care can sometimes seem overwhelming, especially when you’re busy with other things and can’t focus on proper timing.

Don’t worry. The right lawn care service partner in Northern Virginia can educate you on the basics and make you feel comfortable so you know how the process works. That way when you see rainfall, you can relax.

Ready to learn why Turf’s Up could be your totally awesome choice for lawn care services in Northern Virginia? We’re stoked to learn more about you and help you have the best lawn on the block. Get started today with a free quote. Together, we can prepare a customized plan that is perfect for you and your yard.

lawn care service comparison

Get Your Quote