Can I Put Down Crabgrass Preventer and Grass Seed at the Same Time

USING PRE EMERGENT HERBICIDES

Tin YOU STILL PLANT GRASS SEED OR SOD?

Applying Pre Emergent weed killer to a lawn is a mutual Bound chore. Unfortunately this occurs in the aforementioned time frame when we also want to over-seed thin lawn areas, and plant new grass seed in bare areas, or lay down new grass sod.

Weed Preventers ought to be called "Seed Preventers" because they don't exempt your friendly grass sprouts from the warfare being thrown at enemy weed seeds.

In fact, many weeds can be immune to various types of preemergents, just few grass varieties can withstand any of these chemicals.

And then what practise yous do? Yous can hope for the best past working around the unchangeable.  Every yard situation is different, only knowing a few bones principles should betoken you in the right direction.

The Garden Advisor's PreEmergent User'southward Guide will lay out those steps for you.

Many gardeners accept inquired almost their options in specific situations. Permit me share some of the approaches we recommend for them.

See if your backyard crisis resembles any of those and offers good news or bad news for your immediate or long-term prognosis.

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If you lot brand a purchase via a link on this site, I may receive a minor commission on the transaction - at no added cost to y'all.

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HOW TO Co-ordinate
A PRE EMERGENT APPLICATION
WITH LAWN RESEEDING OR NEW SOD

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QUESTION 1:  When Should I Employ Pre Emergent and Reseed?

I live in Kentucky and last yr I power seeded my yard just I think that I was a bit besides belatedly.  I did get some success, only want to know what is the best time to go a pre-emergent downwards?  I don't want to miss this window and I desperately want to use information technology at the very very best fourth dimension.

Also, I do accept an extra big bag of seed that I have left over from last year.  When tin can I apply that in my g earlier information technology goes weak?  It's been kept in my house for 4 1/2 months. I take almost .75 acres and would like to know the kind and amount of pre-emergent to buy.

ANSWER:

Outset, are you lot mostly concerned about crabgrass? If so, y'all want to go the pre-emergent down specifically before the crabgrass germinates. In your area, that should exist awhile, (written in February) but the but way to tell is by soil temperature.

When soil temps go upwardly to about 55 degrees for one-2 days, the crabgrass will start to germinate. A few seeds may seem to outset before then, because temps vary widely even within a minor surface area.
Soil temps are affected by shade, wet and closeness to paved surfaces or walls that soak upwardly heat from the sun. Note: air temps are non a good indication of the soil status.
(Soil thermometers cost about $10.)

If broad-leafed weeds too concern you lot, be enlightened that there is some overlap amongst types of pre emergents. Those tailored for killing crabgrass too impale some broadleaf weeds. Varieties that prevent the largest number of weed species probably won't work on crabgrass. For all of them, notwithstanding, the application must occur before germination.

Bank check with your County Subcontract Agent or Country University Extension plan, every bit they usually provide charts that will predict the typical arrival dates for different types of weeds in your area. The Master Gardeners plan may also be agile in your locale.

Here is the tricky role:
Most pre-emergents for weeds also will
prevent grass seed from germinating.

The 1 exception to this is "Tupersan", also known equally "Siduron".
It can be practical to turf areas of bluegrass, fescue, redtop, smooth brome, perennial ryegrass, orchard grass, zoysia, and some bent-grass varieties. Information technology is non for bermuda grass areas.

The negative sides of Tupersan are a short active life, the cost, and limited availability.

• Information technology is simply good for 4-6 weeks, which means you must time your application carefully to get the nearly do good.
• Equally a specialized chemical, it warrants a higher price. There is no generic version of siduron.
• When found, it is commonly mixed with fertilizer, and so you are forced to buy two products. This makes it less practical for a big area because of the extra cost. (And your lawn may not need those particular nutrients at that time).
• It is hard to detect, not being the herbicide of choice in the common garden products that manufacturers ship to local stores.  Retailers would sell small quantities because they don't have knowledgeable salespeople to promote the production, and the higher cost would allow the bags collect dust.
• The concentrated product (straight siduron, non a combination) may be stocked at professional landscape suppliers or agronomical stores, just in some states they cannot sell professional quality products to "just a homeowner". You tin find information technology on-line; sometimes at Amazon; unremarkably at DoYourOwnPestControl.

If you go this route, you lot can establish your grass anytime that is typical for your gardeners in your surface area. This will also depend on the grass type y'all use.

If you seed a new, bare surface area of soil, every bit opposed to just over-seeding to thicken the backyard, be advised:Do NOT Disturb the soil AFTER y'all spray the pre emergent.
So you must calculate the timing of your application with that in listen if the area will exist tilled or cultivated before planting.

Another "Dimension" To Consider

An Alternate  Product, "Dimension" is an splendid pre-emergent for lawns with a crabgrass problem. It has less of an impact on the roots of grass seedling than many other products.

It is a good choice for a follow up application if your crabgrass season is stretching out and you need more protection after the Tupersan wears off.

Dimension is more accommodating with the timing of application. It can also kill young crabgrass seedlings if you were tardily getting to them (Often effective until the four-leaf stage of maturity).
Merely the newly planted grass must already be upwardly and growing for a while before you utilize this product.

* * *

I cannot suggest the amount you need to purchase or apply, equally this will vary according to the concentration of the production, which tin can vary a lot.  Read the characterization carefully to determine this.

A final note, whatever pre emergent needs to be watered into the soil, (all-time within 3 days), to get it activated in the soil. Schedule your awarding to take advantage of a light rain (not a gully-washer) if you are not able to irrigate. Near ½ inch of precipitation is usually required.

Finally, don't worry about your grass seed. Information technology should remain viable without a significant loss of germination charge per unit for nigh a year. (Much of information technology will last even longer.) A cool, dry location (maybe a closet, or some garages) is better than a warm storage surface area for long term storage, only yours should be fine.

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QUESTION 2: Already Applied
Pre Emergent.  Tin can I Reseed?

I used Sta-Dark-green Crab Grass Preventer and Fertilizer on my backyard 2 weeks ago. I would like to reseed my backyard, and then I bought Pennington Starter Fertilizer and Pennington Tall Fescue Grass Seed to start. Tin I practise this since I already practical the crabgrass preventer?

Reply:

The crab grass Pre Emergent is not-selective, for the most part. More than probable it will inhibit the growth of your grass seed if yous put it down prior to the end of the time limit listed on the Sta-Green characterization.

To clarify, do NOT reseed until you lot are sure that the weed preventer is no longer active.

• If yous put down the tall fescue seed, it volition kickoff its germination process as presently equally the proper soil temperatures have been reached.
• The pre-emergent then interferes with the growth process and the grass volition not develop past the sprout stage.
• But it will be expressionless, not just waiting for a more than opportune fourth dimension to grow.
• The current condition of your lawn requires that you wait before applying the new grass seed so that you don't waste the seed or your efforts at planting new grass.

Sta-Green Crab Grass Preventer specifies that the production tin be effective up to four months, and recommends that yous wait at least 12 weeks after application before reseeding.

There are a few variables that could affect the actual down time. How heavily the pre emergent is practical, how much irrigation it undergoes, and whether or not the soil surface is disturbed, all can lessen or increment the duration of its effectiveness.

Don't forget Murphy'southward Law — the gardener who wants the crabgrass pre-emergent to last equally long as possible won't exist that fortunate… AND…  the do good of a never catastrophe weed preventer will likely go to the ane who is most broken-hearted to start planting!

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QUESTION 3:  Tin can I Use Pre Emergent,
then Lay New Sod?

My lawn has several medium size crab grass patches. I was considering pulling these patches out and then putting down a pre emergent weed killer (can you recommend any?)
And so immediately I want to put down new sod. What practise you think? I live in Ft. Myers, FL. The temps in the evenings is correct at 60.

Answer:

A Pre Emergent weed killer can be an of import weapon in your arsenal to fight weeds, especially the persistent problem of crabgrass. However, your question points out how important it is to get the correct tool for the correct job.

Let's look at the overall nature of the project as you have laid out the steps. Then we'll identify specific herbicides that are appropriate to your needs, and which products would cause a new problem.

I infer that you are actually planning to put downwards pre-grown sod, every bit opposed to planting grass seed (some folks use the terms differently, and so I like to confirm). The two different approaches have a major point of divergence.

Laying sod will require that you remove most an inch of soil to accommodate the depth of the sod and keep it level with the surrounding area. This volition probably remove with it the majority of crabgrass seeds that might be nowadays there. Those that will remain will be not probable to sprout, with the thickness of the sod in a higher place them.

For this reason, you could do this projection without using a pre emergent herbicide.

Yes, you can argue that it is better to be safe than deplorable, and you may not want to let a single weed get a chance to live.
Yes, I have seen it happen that the seams where the sod pieces butt together is the likely place where any crabgrass sprouts might pop through.

Yous must weigh the potential benefit against any potential risk. There is a possibility that the herbicide could interfere with the grass roots pushing out from the cutting sod. The new grass plants would not root into the lower soil layers as rapidly as they would grow under ideal atmospheric condition. This would reduce their heat or drought resistance and overall health.

This hindrance would exist a very definite business with some varieties of pre emergent, and a minimal adventure with other types. Your new sod volition have the best opportunity for getting established chop-chop if information technology is non exposed to any chemicals that can restrict growth.

The other consideration is if y'all were planning to broadcast the pre-emergent weed killer over the entire lawn area, or simply in the bare spots that you need to replant.

Treating the whole lawn is the smart approach for ultimate control, since you can look that the crab grass seeds are widely dispersed everywhere. They volition effort to pop up anywhere they tin can, leaving you with the demand to repeat this procedure time after time.

If this is your intent, so get ahead. Merely remember that you must make concessions for the young grass that would non be a concern for gardeners treating a well-established existing lawn.

Which pre-emergent weed killer will be effective and safe for your new sod?Tupersan… (…rest of paragraph deleted, as it duplicates data from previous questions about this product.)

An alternative would be to wait and detect the area subsequently you sod it, for new crabgrass coming upwards in the grass and hit it with the pre-emergent at that time.

But Wait! ...Isn't it also late then?

Thankfully in that location is a pre emergent that too works post-emergent on crabgrass usually upward to the iv- five leaf stage. Not all pre-emergents will work this way.

You want to get one with the agile ingredient "dithiopyr", usually establish under the merchandise name "Dimension".

Dimension has less of an negative influence on root establishment.

Be sure to read the characterization completely to make sure it is acceptable to employ on your type of turf, at that time of year, and follow the directions advisedly.

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QUESTION iv:  Pre Emergent Is Now Applied.
How Long to Wait before Reseeding?

I applied to my backyard the Crab Grass Preventer by Vigoro.
How long exercise I need to wait before I can sow some new grass seed on the backyard? I was planning on using a slit seeder to apply the grass seed.

(Editor'due south note: a slit-seeder is a auto with multiple blades that slice into the soil; and it is able to dispense seeds at different rates.)

ANSWER:

Permit me give you some general concerns to consider for your situation. I cannot exist exact since I exercise not know which Vigoro product you used.

• It is possible that the active ingredient was Dimension or Benefin, only manufacturers are known to change chemicals without changing the packaging.
• It is essential that you check the label of the handbag you lot used or go dorsum to the store where you purchased to see the criteria on it.

Different pre emergent chemicals can have a residuum effect that ranges from viii − 12 weeks later on awarding, and fifty-fifty longer depending on the strength of the concentration.

This elapsing varies according to the amount of moisture that has been received, also the temperature range and the type of soil, and fifty-fifty unlike varieties of weeds which awaken at different times.

And so you wait and wait, and then yous might run into weeds popping out sooner than the advertised effective date.
You could look that your grass seed should be able to sprout then, right?
Perhaps Non! Read the full answer, before drawing that determination.

An interesting Catch-22/Murphy's Constabulary factor should be considered in your situation.

A pre emergent herbicide forms a barrier in the elevation layer of soil where seeds normally germinate. As the sprout grows into the barrier area, the chemical affects the seed or sprout according to the mode of activity it is designed for, such as stopping cell division for instance.

All preemergents emphasize that y'all get maximum protection confronting weed development when that bulwark zone remains undisturbed. Any disruption of that barrier (any cultivation of the basis) can furnish a 'chemical-costless' path for some sprouts to pass through to the surface without getting zinged.

This suggests, in my stance, that the slit seeder could be a approving or a curse, depending on your timing or your needs.

• If y'all institute too soon using that auto, y'all risk losing the benefit of the pre emergent barrier and face the possibility of a substantial crop of crab grass which will have the advantage over your grass seed.
• There is also the concern that some buried weed seeds will be dislodged past the blades and repositioned to a place where they are more than prone to germinate.
• After you slit-seed, if some chemical is still active, the remaining remainder in the soil could have a killing issue on a high per centum of your grass seed.

The odd thing to consider is whether this gives yous the possibility of breaking the barrier to shorten the waiting period.

• If you lot figure that most of the crabgrass has been killed by a certain signal, then why non go ahead and found?
• If breaking the bulwark allows the grass seeds to germinate and develop, and so could you lot get an before start on the reseeding, correct?

I wouldn't risk that, simply because about desirable seeds, whether grass, flowers or vegetables, are usually hybrids that are more delicate and more sensitive to chemicals or any adverse growing weather.

Weeds on the other hand, tend to be naturally tough, more resistant to assail, and more prone to notice a fashion to survive. Plus, crab grass seeds will be at different depths and prone to germinate over a long flavor.

So if you attempt to short-circuit the designed traits of the pre emergent earlier than recommended, Mr. Irish potato would probable kill the grass and let the weeds through.

So my suggestion is that yous'll get the all-time results with minimum bedevilment by being patient for the entire waiting period listed by Vigoro.

BUT… perchance you're an Action blazon of guy, chewing your fingernails while waiting…..

Then attempt a small test plot first. That will continue you in check so you lot don't lose the investment of your seed, your fiscal investment, and your labor, if the preventer is still preventing.

EDITOR'S NOTE TO NEW READERS:  I realize that doesn't give an verbal answer the question for yous. How Long Do I Look earlier Reseeding?
Is in that location a single reply? Yes.

READ THE LABEL of the product you used/plan to use. Most of the time it states a specific interval to await, mayhap hidden in the fine impress.
If y'all don't see it, contact the manufacturer at their website.
(If they practice non have an FAQ department which gives this info, transport them an electronic mail.)

Don't guess or presume. Even the same active ingredient used by 2 products tin have different active lives considering of concentration or method or flavour. Exist rubber. Avoid disappointment.

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Go to PreEmergent User'due south Guide

Get to My Garden Needs: Weed Preventer for a selection of Pre Emergent products

Go to When To Use Crabgrass Preventer

Get to Garden Counselor Abode Page

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