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The Daily Insight

Can you put fungicide on new grass?

Author

Matthew Barrera

Published May 24, 2026

Can you put fungicide on new grass?

After you see the symptoms, it is probably too late to apply a fungicide because most fungicides are preventative, not intended to cure existing infections. If you water and fertilize your new grass properly, brown spot or dollar spot probably will go away on their own.

When should fungicide be put down?

We recommend beginning lawn fungicide applications when nighttime low temperatures rise to 60°F. Typically, preventative applications are made at 14 to 30 day intervals, depending upon the fungicide. There are an abundance of lawn fungicides available that prevent brown patch and other lawn diseases.

Can you spray fungicide when its hot?

Propiconazole can cause damage to turf in hot weather. The effect isn’t from the spray sitting on the leaf, but is possible as long as the fungicide is in the plant, so you can have effects weeks after application if it gets hot. It isn’t going to kill the grass, but may result in off color or slight browning.

How long does it take for fungicide to work on grass?

Most systemic fungicides need at least 7 days to take effect but then can remain effective for over 25 days. Contact fungicides work immediately but are only effective for 3 – 8 days or until the protective layer washes off.

Do you water after applying fungicide?

Contact fungicide Contact fungicides are fungicides that remain on the leaf of a plant (the grass leaves in the case of a lawn) and fight fungal infection by providing a protective covering over the leaf. This means you should avoid watering your grass after applying a contact fungicide.

What causes Bermuda grass to brown in spots?

The brown patches or dead spots will start to show during the warmth of the hot summer days and the moisture from nighttime irrigation you do on your bermuda grass lawn. With time, fungal residue inhibits photosynthesis, as the fungi gradually spread across the grass leaves, leaving dead spots on the infested areas.

What temperature should I spray my fungicide?

Like most products, Southern AG Insecticides Liquid Copper Fungicide should not be used in temperatures over 85 degrees. We usually recommend to spray early in the morning or in the evening when the temperatures are usually cooler. Spraying in the heat of the day will cause the foliage to burn.

When do you need to put fungicide on Bermuda grass?

Sometimes a fungicide may be needed to suppress the fungus growth and protect the grass from attack during periods when conditions favor disease development. Remember that control and management of the disease are key. Don’t wait until you need a fungicide.

What to do about brown patches on Bermuda grass?

To control brown patch, fertilize bermudagrass moderately in summer and if you irrigate, do it in the late evening or very early morning. There are lawn fungicides available to control brown patch. Read the label carefully and use the rate and timing that is indicated. Management plays the most important part in brown patch control.

When to apply fungicide to brown patches on lawn?

If your lawn had brown patch last summer, applying a preventative fungicide in the spring and throughout summer is a smart idea. Like weeds, some lawn diseases are more active in the spring or summer and some are more active in the fall or winter. Read our fungus and lawn disease guides to learn more about when certain diseases are most prevalent.

Can a fungicide stop the spread of grass disease?

Unfortunately, fungicides cannot completely “cure” grass or plants that have already been affected by a lawn disease. However, if applied quickly enough, fungicides can stop the spread of the disease and help plants recover from disease. Fungicides also do not control or prevent damage to grass or plants caused by insects.

What should I spray on my Bermuda grass?

Once you have located one of these areas, spray with a lawn fungicide approved for use on Bermuda grass. In your lawn has a history of fungal problems you may want to renovate the dead areas and then spray preventatively with a lawn fungicide the following year so that the disease does not recur.

When to apply pre emergent herbicide to Bermuda grass?

Applying 1 or 2 pre-emergent herbicide applications in the spring and 1-2 in the fall will help Bermuda grass fight off invading weeds. Pre-emergents contain weed control that prevent weeds from growing above the soil and into your lawn.

When to fertilize Bermuda grass to get rid of brown patches?

To control brown patch, fertilize bermudagrass moderately in summer and if you irrigate, do it in the late evening or very early morning. There are lawn fungicides available to control brown patch.

If your lawn had brown patch last summer, applying a preventative fungicide in the spring and throughout summer is a smart idea. Like weeds, some lawn diseases are more active in the spring or summer and some are more active in the fall or winter. Read our fungus and lawn disease guides to learn more about when certain diseases are most prevalent.