When to Put Down Pre Emergent in Spring

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When to put down pre-emergent in spring?

← Best granular pre-emergent, click for pricing.




From our → Pre-Emergent Page

Pre-Emergents have a MAXIMUM annual application rate / dosage clearly printed on the label. Do not exceed the maximum annual amount. If you plan to do more than one treatment in a season / vary the usage / brand of the product / chemical. Click picture to better understand. 

If you plan to do the double treatment Doc does, VARY THE PRODUCT and use the lowest application rates on the label for each product.  (Read more below) 

#1 – Target your WEED at the right time.

You apply a pre-emergent based on the weeds you want to PREVENT for the next 3-5 months.  Example: There is no reason to worry about CRABGRASS in the late fall, going into winter, but you would want to target Poa Annua and other winter weeds / grasses.   However, you WOULD want to make sure your preemergent stopped crabgrass when putting down in March or April. (based on your zone).

#2 – Many liquid pre-emergents cover a broad spectrum

Many products listed below will cover a broad spectrum of target weeds. So make sure you read the label and make sure your TARGET weed is covered. They often cover crabgrass even though you are not targeting it. (Such as fall and winter) But that’s OK… they’ll stop those darn winter weeds like chickweed and poa annua.

#3 – Vary using both light treatments of granular and spray for best results.

We have found the best results from applying at a LOW RATE of each listed on the label. You can space these out a few weeks in-between.  Example… a low rate of granular early in the spring / late winter and then a LOW RATE of the liquid right on time a few weeks later. Generally you only need one treatment in the fall. By law… you have to follow the label which means you may be limited to “X” number of applications or maximum rates per year.   Finding a BROAD SPECTRUM granular is not easy.


We try to write these instructions at an “8th grade reading level”… but some have suggested that we say OVER APPLY pre-emergents.  That is NOT what we are saying.  Apply ONE chemical in granular form lightly… then come back a few weeks later and apply a different spray chemical LIGHTLY.  Example: Barricade DG then Dimension (shown below).

PRE-EMERGENTS stop seeds from developing and inhibit new root growth at a shallow level. (1-2″) New sod should never have pre-emergent applied. We suggest a FULL YEAR of growth before using light treatments on NEW SOD.  Instead use a post emergent to control weeds and be patient.

For most people the target soil temp we want to watch for is 50 degrees.

Attack Early and Attack Twice

This is the most critical step in lawn care. Let me repeat that… spring pre-emergent treatments are the most important step in a great looking lawn. They prevent you from having to use NEGATIVE chemicals on your lawn later in the growing season.

Some warnings…

Before starting: Always adhere to the label’s annual restrictions amounts.  Each pre-emergent will have a maximum annual application amount printed clearly on the label. Do not exceed. Click the image below to better understand. 

If you have new sod, laid down within 6 months, do not use pre-emergents.  If your sod is 6 -24 months old, use pre-emergents sparingly.

#1 Buy them early

Your best researching and timing efforts don’t mean a thing if you can’t get it.  Pre-emergents sell out quickly come March 1st and you should order early. Granulars are the toughest to get due to the shipping methods and stocking. So…→ ORDER NOW.  You can see them HERE. I have had a bag of the Barricade DG in my garage for two months.

#2 Don’t be fooled by ground temps…. be early.


“Crabgrass seed germinates when spring soil temperatures tend upwards from 50 degrees F. Weed scientists use 52 degrees F. at one-half inch deep as the trigger point for their application of pre-emergence herbicide.”

WHATEVER YOU DO… don’t be late.  In middle / upper GA the rule of thumb has always been March 15th. That is WRONG. The rule of thumb really is BE EARLY. Soil temps can quickly shoot up and we have seen 50+ soil temps in the past as early as late February. YES… I said February.   Knowing this… and knowing that pre-emergents last for 2-6 months, WHY ON EARTH WOULD YOU NOT PUT THEM DOWN EARLIER?  I will be putting down my first granular treatment come Feb 15th.  I will then do a follow up treatment around March 15th with a spray.

Following this ATTACK EARLY and ATTACK TWICE routine has virtually eliminated 100% of weeds in my lawns.

#3 Don’t rely on just ONE treatment.

I really like the Barricade DG put for my 100% peace of mind… I always followup with a second treatment of a spray pre-emergent. (varying the main chemical used) Again, the granular goes down early and the spray goes out about month after.  Sine I have been doing this DOUBLE TREATMENT… I have ZERO and I repeat, ZERO weed issues in my lawn.  Even though I am surrounded by lawns infested with weeds, my lawn is awesomely free of weeds.  Again, as stated on almost all the pages here, do not exceed the annual application rates for any product.


Have new sod?  Pretty much everyone agrees. Keep away from applying pre-emergents on new sod. It can hinder root growth. Just deal with the weeds the first year and then we’ll attack them next year.  Use a small amount of POST EMERGENT control for new sod.

#4 Look up historical soil temps

This is a great website to look up soil temps and years past. Punch in your zip code and your done.  Go to the date and look up years past.

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