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When Do You Put Down GrubEx?

April 5, 2013

If you have ever had grub problems in your lawn, it’s for darn sure you don’t want them again.  So this time of year I get the question:  “When is the best time to spread GrubEx on my lawn?”

For those of you who know all about grubs you do not need to click here to read a blog posting I wrote last year that explains the grub cycle and how you protect your lawn from being destroyed.  You just want to know when is the best time to put GrubEx down since there is such a wide application time frame listed on the package.  You will also note a direction on the package to not apply to waterlogged soils and to water after application.  Since the soils tend to be very wet this time of year and since the grubs will not be laying their eggs until summer, I asked our researchers when they apply GrubEx to their lawns.  Their answer:  May.  (If you are reading this and May is in your rearview mirror and you have not put your GrubEx down yet this year, apply as soon as you can up until late summer.)

So I follow their advice and put my GrubEx down in Early May.  Click here to get more info on Scotts GrubEx.

Grubs eat grass roots resulting in brown, dead lawn patches in fall and early spring

Grubs eat grass roots resulting in brown, dead lawn patches in fall and early spring

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  1. Jim Casteel permalink

    I got a bad case of moles last year. Should I put down Grub X or Bug B Gon?

    • Hi Jim
      GrubEx will take care of grubs (one of the primary things moles eat). Bug B Gon does not take care of grubs. Apply your GrubEx in May. Regarding the moles, understand that they also eat earthworms, so you could still get moles in your yard going after the earthworms. Of course, GrubEx will get rid of one of their primary food sources. If you get moles, you can trap them, bait them or repel them. If you trap or bait, you need to find the most used “run” or tunnel by stepping on 6 locations to flatten out, then checking the next day to see which place is raised up. This is the most active tunnel and the best place to set the trap or bait. Ortho has a Mole repellent you can treat your lawn with to discourage them. But, you are on the right track with GrubEx.

      • If I don’t see evidence of moles, does that mean i don’t have grubs? Years back we had so much rain with a tropical storm, the grubs floated on top of the water and I gathered them in a bucket there were so many. Haven’t seen many since.

      • Hi Diane
        You can have a grub problem without having a mole problem. Since you have not had a grub problem in recent years, here are some things to watch for so you can determine if it would be a good idea to put down GrubEx in early Summer. In early summer watch for Japanese Beetles feeding on roses and other plants, also watch for the brown or green beetles attracted to your porch light at night. These are some of the adults that lay eggs in your lawn during mid summer that will become grubs. If you anticipate grub problems, the key is to get your GrubEx down before the eggs are laid.

  2. Phyllis Harry permalink

    Where can I buy grass seed that will grow in sand and shade? For zip code

    • Hi Phyllis
      My question back to you is how much shade does this area of your lawn receive? If you are getting at least 4 hours of sun (it can be filtered sunlight through tree leaves), you can grow grass in that area. Less sun than that and the grass will always be thin no matter what you plant. The seed blend I suggest for your sandy soil and your area in Indiana that will tolerate quite a bit of shade is Scotts Turf Builder Heat Tolerant Blue Grass Seed Blend. Be sure to put down Starter Lawn Food when you plant your grass seed.

  3. Skip Berry permalink

    Does the application of GrubEx have to be timed around my Step 2 Weed/Feed application. Didn’t know if there was some minimum time I should separate my 2nd Weed/Feed and the GrubEx

  4. Scott S. permalink

    Can I spread Scott’s Water Smart Seed after applying Scott’s step 1 fertilizer with crab grass preventer.

    • Hi Scott
      You can put down grass seed ONLY if you have put down the special Step 1 Starter Lawn Food plus Weed Preventer. This product is compatible with grass seed, while the regular Step 1 will keep your new grass seed from germinating.

  5. Terrell permalink

    Can I put down grubex and grass seed in the same week? Or how long do I need to wait?

    • Hi Terrell
      Yes, you can put both down during the same week. The typical timing would be to do grass seed ASAP so it will begin to grow as the soil warms, and to wait to put GrubEx down in May since this application is targeted against the next generation of grubs that will begin to show up in late summer. If you are seeing grubs in your soil now, these are likely doing no damage now, will soon become beetles and GrubEx will not kill them at this stage.

      • Jim Casteel permalink


        If my yard is a “hybrid” of different grasses, one of the primary is Bermuda, is there a recommended method to getting it all to “Tall Fescue?”

        Thank you in advance.

      • Hi Jim Converting your lawn from a mixture of different grasses including Bermuda to Fescue can be tough to do. The process would start in mid summer with Roundup over the entire lawn. A week later spray Roundup again to get the grasses you missed and to hopefully keep the Bermuda from coming back. (Make sure you are using regular Roundup and not one with Extended Control.) A week later you would Dethatch heavily or slit seed to get your grass seed in contact with the soil. Scotts Heat Tolerant Blue would be a good mix. Feed and water your new grass in fall so it has a good root system the following year. In fact, a couple of fall feedings would be good. A more simple approach than killing your entire lawn is to seed your existing lawn each fall with Heat Tolerant Blue and allow all your grass types to coexist. Over time you will increase your fescue content, especially with a heavy fall feeding schedule.

      • Jim Casteel permalink


        Thank you! We have a “slight majority” of Bermuda and therefore from late fall until early summer the yard is brown. My sweet wife comments about a “couple” yards in particular that have “fully green/grass” yards. I am thinking of following this plan from you/Scotts (please advise):

        1) Now, Scotts fertilizer with Halts
        2) 6 weeks from now, Scotts Weed n Feed and Grub EX
        3) 6 weeks after, Summer Guard
        4) Dethatch, aerate and seed (Heat Tolerant Blue) (starter fertilizer)

        What do you think? Do I do anything after 4) above?

        What do I do next year (assuming it will take a couple/three years to get rid of weeds and a good root system of Blue (living with the Bermuda).

        Thank you again.

      • Hi Jim
        The only thing I would add to this plan is to do a follow up feeding in the fall about a month after seeding with Turf Builder. Over time as you get more of the Heat-Tolerant Blue blend established in your lawn, you will favor it and not your Bermuda by doing heavy fall feeding and an early spring feeding, then dial it back in late summer and summer when the Bermuda is looking for that extra food.

  6. Jeff permalink

    this is jeff can i mix scotts grass seed with scotts starter fertilizer do it all on shot and do i have to water right way

    • Hi Jeff
      You can put your seed and your Starter Lawn Food down the same day… just not in the same spreader pass (the spreader settings are different). You will need to make two trips over your lawn.

  7. Jeff permalink

    ok cool thanks

  8. I am a new homeowner in Michigan with grubs. After applying Grub-ex, how long should I wait to apply seeds?

    • Hi Jermika
      You can seed anytime now. Please understand that GrubEx you apply now is to kill the next generation of grubs that will show up in summer, not any grubs you may be seeing in your soil now. The grubs that are present this time of year are just about to shift into the pupae stage and become beetles.

  9. Will I be able to get any progress? I was told by a landscaper that I need several treatments before I seed. $60 a application, so I was thinking of doing it myself.

    • Hi Jermika I am not sure what your landscaper was planning to use. GrubEx is not for mature grubs. There are some insecticides on the market that claim to kill mature grubs. My thought is that any grubs that are present now will not be doing any more damage as they will be shifting to the pupae stage to become a beetle, much like a caterpillar goes into the cocoon stage to become a butterfly.

  10. Should I seed before putting down GrubEx? Can I do it all in one day? I love your blog! Its so informative for new homeowners like myself!

    • Hi Jermika GrubEx will not keep grass seed from growing. You can put it down anytime this month to prevent the next round of grubs from being a problem. I would put the grass seed and Starter Lawn Food the same day. Glad you are finding my blog helpful!

  11. I have been to a few sites about my ” Out of no where, out of conrol Grub issue” , and I am very pleased to see a response to every question!!! Very informative, Thank you!!!! Also other sites said other things. So you answered my question about how long I have to deal with the skunks, and watching every move my dog makes!!:) But I have GrubEx ready to go!!!!! From upstate NY

    • Hi Kathy
      Sounds like you have a perfect plan to take care of the next round of grubs this summer. Apply this month and be sure to water after application.

  12. Rosa Espi permalink

    How do i repair the damage that grubs and moles have created in my lawn? I bought grub ex and weed and feed, but i think that will only kill the grubs and dandelions whats the next step? Thank you in advance.

    • Hi Rosa
      If you have extensive damage with lots of bare soil/dead areas/damaged spots, you will need to seed. If your bare spots/dead areas/damaged spots are only several inches across, then your existing grass will fill in when you feed it. If you do need to seed, then be sure to follow the directions on the weed and feed about seeding before or after applying. The GrubEx can go down anytime over the next 4 weeks or so and will protect from the next round of grubs that will show up in late summer. If you have a few spots to seed, Scotts EZ Seed works well, just be sure to not spread the Weed & Feed in those areas.

      • Jim smith permalink

        Does grub ex kill grass seed?

      • Hi Jim
        No, GrubEx does not kill grass seed.

      • Rosa Espinoza permalink

        Thank you for your quick response! One last question does Grub Ex burn grass like fertilizer does when you over do it?

      • Hi Rosa
        No you will not burn your grass with GrubEx.

  13. Jodi permalink

    my dog eats a LOT of grass……. will the grub ex after it has been applied, water & dried, hurt my dog?

    • Hi Jodi
      Water real good after application, allow grass to dry and then all is ok for your dogs. (Our cats eat so much grass I wonder why we spend so much on cat food.)

  14. can I use my weed killer for lawns and grubex at the same time?

    • Hi Chantal
      Since the weed killer goes down when rain is not expected and the GrubEx should go down when rain or watering is expected, the timing is different. I like to allow a week between all my lawn applications.

  15. Greg permalink

    I have recently encountered a grub problem. Large sections of my yard have died, and I’ve found grubs in the lawn. We have a acre yard that needs to be treated, and we live on well water, so I’m not able to water in due to the stress on the well. Can I apply grubex before a rain, and let it wash into the soil? When should I apply grubex?

    • Hi Greg
      You can apply GrubEx prior to a rain rather than watering after application. Apply anytime in May/June, the sooner the better. This application protects against the next generation of grubs that show up in late summer. Any grubs you are seeing now have completed their grub cycle and will soon become beetles.

  16. richard rutkoskie permalink

    Grubs are only 18% of moles diet. Part are worms, that you can’t eliminate what do you do now?

    • Hi Richard
      You hit on a fact that lots of folks do not understand. You protect against grubs with GrubEx, you will still have earthworms, the primary diet of moles. Here is a good website on trapping moles:

  17. Joseph permalink

    I just found this Blog, and I love it. I am also a new homeowner and learning the ropes of building a nice lawn. However, the previous owners just did not take care of it. So I have ALOT of problems with it. Grubs, Ants, Clover, Moss, Various weeds that I don’t know what they are. So it is slow. I missed the May Grubex. Gonna try and get it on this weekend(mid June). But my big question is what do I need to do next. To kill most of the “other” plants in my yard, and prepare for a seeding(which kind should I get, mostly sunny, Grand Rapids, MI) in the fall.


  18. Ed C permalink

    When i put down my Grub ex in May, i still found plenty of grubs. Does that mean my application last year didnt work? How do i prevent the grubs from turning into beetles. The japanese beetles are destroying my Linden Tree.

    • Hi Ed C
      Your application last year would get the highest percent control with a May or June treatment and if the soil was not saturated with water when applied and if you watered after application. 100% control is not likely even under ideal application timing/conditions. The goal is to get the population down to the level that no turf damage is noticed. Regarding your Japanese Beetles, Ortho Bug B Gon Spray does a good job when the insects are present. Another option is Ortho Tree & Shrub Insect Control as a systemic treatment in spring to be absorbed by the tree roots prior to insects showing up.

  19. Jon permalink

    I live in Southwestern PA. Do not have obvious grub or mole problem. Have not treated lawn for 3 years with Grubex.

    Should I apply Grubex now or wait until next spring??

    • Hi Jon
      You are in an area that has grub problems. GrubEx kills grubs as they hatch and begin to feed. If you are seeing lots of beetles flying around your porch light or feeding on your roses and other plants, GrubEx applied now will take care of the grubs that come from the eggs they will lay in your lawn later this summer. If you were to wait to apply next spring, you would not really be taking care of this grub cycle, but the one that willhatch from the beetle eggs laid next summer.

  20. Ed C permalink

    Thanks for your reply to my previous questions! A couple of follow-up questions – Is it OK to spread Grub-Ex through perennial beds? while planting or transplanting, i have seen adult grubs in my perennial beds.

    And, is there any harm/benefit in apply grub-ex twice in one season, say once in early May, and then again in early July? I have very sandy soil, and i wonder how much of my product just goes straight through after watering.

    • Hi Ed… We need to stick to the recommendations on the label, which says GrubEX is for use on lawns. I don’t think you need a second application even though you have sandy soil. The key is that your grass plants capture the ingredient in the root zone to protect the plants from grub damage. If you are only seeing a few grubs in your perennial beds, I would not be too concerned. Ortho has several systemic insect control products that can be used in shrub beds.

  21. Shannon permalink

    any idea if this will help with voles; my dog brought one to the door and i think this is what is killing my vegetable garden; Although I know voles only eat plants

    • Hi Shannon
      GrubEx will not keep your voles in check. You are right, voles can hurt plant roots. Ortho has a new repellent called Mole B Gon which can also be used for voles.

  22. Giovanna permalink

    I didn’t apply GrubEx last year and this year an area of grass is so damaged that I want to tear out any remaining grass and lay down a better base of topsoil and new sod, should I apply another round of GrubEx to this area before the sod goes down? I know grubs emerge in Spring but wonder if it would still be beneficial now. I want to lay the new sod here in Michigan by mid October, thanks

    • Hi Giovanna
      It is late to apply GrubEx for this year’s grubs. The best timing is to apply sometime between May and early August prior to eggs being laid. You then do not need to worry about grubs this fall or next spring. Having said that, I think you are going to disrupt any young grubs that are in your lawn now as you are getting your soil ready for sodding. If you see lots of grubs in your soil as you are preparing for sodding, you could treat the area. Scotts does not have a grub control that will provide this immediate kill. Check with your local garden center or home center for a recommendation of a product that will provide 24 hour grub control.

  23. Chas permalink

    OK, it’s mid-late Sept. in Virginia (DC area). The turf is coming off like carpet. Bare dirt everywhere. Obvious grubs, some live, some dead. What do I do? (Yes, I know, apply grub control in May…that’s months away!) Kill the live grubs now? With what? Seed? When? Fertilize? No pets or kids. Thanks.

    • Hi Chas
      I am sorry to say that I do not have a Scotts or Ortho product to recommend that will give you a quick grub kill. GrubEx is best applied prior to eggs being laid in August as you have cited. Check with your local Garden Center for a product that will provide 24 hour grub control. This is a good time to seed in your area. Scotts Heat Tolerant Blue Grass Seed Mix is a good choice. Put down a Starter Lawn Food when you seed.

  24. John permalink

    Just had lawn aerated, seeded, and fertilized. Lawn care service noted a grub problem and offered treatment now as well as a program starting next year. Should I go ahead and treat now or wait until the Spring/May of 2014? I live in NC so we are around mid 50’s to 60 in the evenings and mid 70’s in the afternoons. In short, any advantage to doing treatment now?

    • Hi John
      The treatment this time of year is a different material than the one used in spring/summer. This treatment provides immediate control of existing grubs. Scotts and Ortho does not sell a product for this purpose. The treatment in spring/summer is a single application of GrubEx to prevent grubs. This is the best choice however next year’s treatment will be for next year’s generation of grubs that will show up in late summer/fall. If they found a high concentration of grubs now, you should have them treat with the material that provides 24 hour grub control. You should also treat next spring/summer

  25. joetoronto permalink

    Hello, I live north of Toronto and we had a very high amount of crane flies this August and into September, they’re finally gone, I think.

    Anyway, I understand they come from grubs below the grass. My question is, should I wait until May to apply Grubex, or apply it now and in May too?

    • Hi Joetoronto
      Yes, Crane Fly larvae is a type of grub-like worm called “leatherjacket” that feed on grass roots. GrubEx is not sold in Canada, so I am sorry to say I do not have a recommended solution for your problem.

      • joetoronto permalink

        I see, what about my house in Niagra Falls, NY?

        I have the same problem there.

      • Hi joetoronto: The first strategy is to keep your lawn well fed so you maximize root growth. With healthy roots, your lawn can tolerate a small population of leatherjackets. You can apply GrubEx next May or June to prevent both white grubs and leatherjackets next fall.

      • joetoronto permalink

        Cool. Thanks so much, Ashton.

  26. Linda permalink

    My lawn was a mess and trying to bring it back the last couple years. Using Weed and Feed, additional hand sprayer for weeds, and hand pulled 4 bags of crab grass. Im winning the battle with crab grass and dandelions:) Now working on the bare spots with seeding and trying to avoid not know what I needed to do.

    I understand most everything you have said. You mentioned if May was in the review mirror, apply Grubex by late summer. Well, there are no dates when the questions were presented. As I write this, we are approaching October 2013. I just did Weed and Feed last week. Should I use Grubex now as well. I hear what you are saying about their life cycle. Grubex is expensive. Would there be any benefits to apply Grubex in Oct or should I just wait and do in May? How many times a year do you use Grubex? Linda in Souderton Pa

    • Hi Linda
      You apply a single application of GrubEx sometime between April and August to protect against the cycle of grubs that hatch in late summer. Scotts or Ortho does not have a grub control product that works on grubs you may find in your lawn now and next spring. You mentioned seeding and weed control. Weed controls can reduce grass seed germination and can injure young seedlings. The best timing is to wait a month before seeding after putting down a weed controls that kill dandelions. Once you have seeded it is best to wait until the seedlings have been mowed 4 times before putting down any weed controls. Be sure to put down Turf Builder with Halts Crabgrass Preventer around April 1 next year. If you plan on seeding in spring, use Starter Lawn Food plus Crabgrass Preventer instead.

  27. Linda permalink

    Your info on seeding and Weed & Feed timing is something I didnt take into account and I might have been my own worst enemy with some of the bare spots. Thanks so much for the info and speedy reply. I copied this whole thread.

  28. Mary permalink

    It’s the first part of October and the moles have appeared. With it being so late can I still put Grubx down or is it just too late?

    • Hi Mary
      It is too late to put down GrubEx for this year’s grub cycle. The moles may be feasting on earthworms, which are not killed my GrubEx. Ortho has a new liquid and granular Mole-B-Gon repellent this year. I have not had a chance to use this myself. Many of the mole experts suggest trapping. Here is a link to a website that talks about everything moles including trapping:

  29. Barbara permalink

    I just discovered I have grubs…it’s October and a section of my lawn has been invaded by critters ( skunks?) since the lawn looks as if it was thatched. Can I apply grubs now..October? Help

    • Hi Barbara
      We do not sell a product that provides the kind of 24 hour grub kill that you are looking for this time of year. Sorry. Check with your local garden center to see if they carry a product of this type. Our GrubEx is best applied spring to late summer prior to beetle eggs hatching into grubs in late summer.

  30. Dick Roeber permalink

    We had grubs last year, and GrubEx seems to have cured the problem.We have power rakes, fertilized and done our first mowing this spring. The sprinkler system is on, and We expect to aireate next week. Would you apply GrubEx before or after aireating?

  31. chris m permalink

    Just put down Step 1 last week before a good soaking rain in Massachusetts. How long should I wait before putting down my Grub X?

  32. Irene M permalink

    Just had Grubex put down today. It is going to rain in two days. Is that okay or should I water sooner?

    • Hi Irene M
      I have been in the same spot as you on previous occasions. And, then the rain did not happen and I wished I had watered. Watering would be the safe bet. Rain in two days is almost as good if it actually happens. Good Luck.

  33. ian permalink

    How long after i apply Grubex can i go back and rake up all the dead grass?

    • Hi Ian
      Once you have watered at least a half inch after putting down GrubEx, you can rake. If your grass still has some roots attached to the soil, I would be careful not to rake too hard since your grass may root down into the soil again if it is still alive (like new sod). Feeding with Turf Builder Starter Lawn Food for new grass could help if you have not fed recently.

  34. Susan doucette permalink

    How often can I put down grub ex?

    • Hi Susan Doucette
      One application of GrubEx between April and Mid Summer takes care of the next generation of grubs that will show up in late summer/early fall.

  35. Renee permalink

    Can I apply grub ex and summer guard at the same time? During the same application?? Thank u in advance

    • Hi Renee
      Ideally you would allow a week between applications of any two lawn products. If this is not possible, you can spread these two particular products the same day since they both require watering afterward and they are compatible. I would spread the SummerGuard first since it contains lawn food, this way if you happen to get spreader wheel tracks mixed up from the two applications you would not have under or over fed areas of your lawn.

  36. Linda Williams permalink

    Is it safe to eat tart cherries from a cherry tree that had Grubex applied on the lawn around it?

    • Hi Linda Williams
      I understand that the active ingredient in GrubEX is used on many fruit crops in commercial agriculture, including cherries. Hope this helps.

  37. Steve Taylor permalink

    I applied GrubEx in April but with this crazy weather (Midwest) is it best/safe to apply a 2nd application?

    • Hi Steve Taylor
      Your lawn should be protected from the next round of grubs that could show up late summer/early fall. If you believe your control could be reduced either because the granules were not watered in after application or because they were applied to lawn areas with super saturated soils (where you may have had standing water) and you have had big grub problems in the past another treatment could provide some peace of mind. But with normal application and conditions your April application should do the trick just fine.

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