View Full Version : Overseeding and spring pre-emmergence applications

02-23-2009, 02:29 PM
I have a customer who wants a spring overseed and later a early spring pre-emmergence for weeds and crabgrass. What time frame do I need between these 2 applications? Thank you in advance for your help.

Barefoot James
02-23-2009, 09:16 PM
Dormate seed asap - cover with a thin layer of compost. Seed needs to get down before about the 15th of March and hopefully if the weather cooperates you will have till about May 10th before you need to put down pre. They say crab grass starts to germinate after May 10th in your area. April 20th for us here in Louisville - so pre needs to get down by those dates or you can get germinating crab grass and other weeds. I would only use a half app and then the other half by the middle of June. This should keep the crab down and not hurt the new grass or just germinated seed.

I have dormate seeded many yards already here. Never gaurantee any spring seeding as it is a complete crap shoot for actual grass germination rates - unless you are doing Bermuda or Zoyzia. For fescues, ryes and KGB's you are completely at the mercy of weather temps.

Fall is the only time I can gaurantee it. Cause we are going to get the temps we need and with or without rain we can control the irregation. Spring seeding does need to be keep moist - but usually we get plenty of rain - it is the slow ground temp warm up that is the cause of irregular grass germination rates - especially wen getting it before the crab grass can.

Good Luck

02-23-2009, 11:12 PM
First off, your fighting one with the other. If you apply your crabgrass control then you cannot seed lawns unless you have like a scotts product or another product that still allows seeds to germinate. Crabgrass preventers put a barrier on the soil surface which wont allow crabgrass or any grass related species to germinate. So if your going to put premergence down make sure it still allows grass seeds to germinate, or just wait till fall to seed. In terms of when to apply crabgrass pre emergence they use a good general rule of thumb that is when your forsythia bush starts to bloom or is in bloom put down your crabgrass control. Crabgrass needs atleast 3 days of 50 degree soil temps or high before it starts to emerge. In terms of seeding, spring time is not the best for seeding but most people do it anyways. The reason why its not that great is because the soil temperatures are still very cold so it takes longer, and the competition with weeds germinating in spring. In your area I would recommend for applying seed about mid april

Barefoot James
02-23-2009, 11:26 PM
tombo - I would not wait to get the seed in the ground for spring (april means you miss lots of opportunity to grow some grass). Granted fall is best and only reliable option but 2nd option is dormate seeding and allowing as much seed to germinate as possiable (take advantage of all the rain) before the drop dead date for doing pre - emergent. if you want to buy more time - cause it will cost you plenty - seed several times starting now and when May 10th rolls around use tupersan as the pre but which will give you till June 15th and then add about 3/4 dose of a regular pre like barricade. but tupersan cost a fortune but will allow the grass seed to germinate and keep crab away for about 30 days.

02-23-2009, 11:37 PM
James, I guess its all climatology really. Just going by my general area, the soil temperatures are still very cold here and the root growth is doing nothing as well as the top growth. I saw he is from columbus oh, not being from that area but realizing they are colder then where Im from I was thinking early-mid april until the grass itself is growing. It also depends on what type of grass seed you put down. We all know if you put down poa pretensis your going to wait a 2 weeks before germination, but lolium species take 4-8 days to come up, with fescues a little after that. So grass species also has to be determined. At my golf course we use barricade and dimension.

02-23-2009, 11:39 PM
also when applying grass seed either aerate the soil or scarify the soil dont just throw the seed on top of the soil that wont do anygood unless it falls in cracks or other holes

Barefoot James
02-23-2009, 11:52 PM
Good advice - tombo

I never had much belief in dormate seeding either until the University of Kentucky turf grass professor AJ Powell told me about it. It works much better to let the temps control IF and when it wants to grow the grass - so you have a better chance of having grass without crab. It can be much cooler than you think to grow fescues and even rye than what crab requires. Plus the fesue seeds are up on top where that days sun can make it pretty warm - while crab is down an inch or more. i also like to cover seed with about 1/16 (dusting of compost) this really gets the germination rates up and feeds the seedlings.

I would recommend using a Turf Revitilizer Power Seeder to apply the seed. You can rent them at most Home Depots in OH - or get a 9hp one. they are awesome.

02-23-2009, 11:57 PM
Yea its all determined by the weather. Like you said about the heating of the day warms the top of the soil, the cold of night can also freeze the top layer of the soil quickly. Good point, with the dusted compost over the seed. We use penn mulch or a fine wood chip mulch thats is finely pulverized up no big chips. The mulch aides in heat and holds in water to help the seed germinate quicker.

02-26-2009, 10:09 AM
Seed early, You can apply tupersan as a starter fert w/ crabgrass control product that you can still seed with. It is very expensive. The other option is to use a post emergent control later on after the new turf is established. Keep in mind that getting a thick stand of grass will help shade out the crab, you never see crabgrass grow in the shade, it likes it hot, and it loves the sun.

Jason Rose
02-26-2009, 10:34 AM
Yes, A Tupersan product, they usually blend it with a starter fert (both expensive). Seed ASAP, and once it's growing well put your regular preemergent down. I recommend Dimension, as Pendi or Barricade are more prone to damage the roots. If you don't feel comfortable applying the Dimension yet, hit it again with the Tupersan 30 days after the first app. That's all the longer it usually lasts, 30 days.

Best of luck, I despise spring seeding. I've seen it done and if it's seeded at a higher rate and fed well it CAN get estiblished and choke out most of the weeds. Still have to apply pre for the crab in the mid spring and still must spray for broadleafs once or twice...
I see so many homeowners spring seeding, and it pretty much always ends up being a weed patch by summer. Spring is just tough because it takes so long to germ because of the low soil temps.

02-26-2009, 11:58 AM
Spring seeding is best after the snow is gone and the freeze/thaw cycle is regular. Farmers would often seed ryegrass during this time because the freeze/thaw worked the seed into the ground.
Once germination starts it doesn't hurt to put down some more seed and compost is essential for full quick germination.

Most pre-Ms work on the basis that AFTER germination the chemical is absorbed by the plant and it ability to grow roots is stifled.

Someone on this forum had applied pre-m to newly sprouted grass plants at 1) first leaf stage, 2) the two leaf stage and thirdly the 3 leaf stage.
His discovery was that the plant will survive the pre-m after it has 3 leaves of growth.

So 10 days after the second seeding - start counting the leaves and get ready to pre-m if you want. The need to pre-m simply means a poorly managed lawn IMHO. I haven't found a need for it after a couple of seasons.

kenny s
02-27-2009, 06:53 PM
When you say cover new seeding areas with compost, what can be determined as compost? Can you for instance, use peatmoss? This could be costly if you are covering a newly powerseeded area of several thousand sq. ft or more. I live in northern New Jersey and am new to power seeding, so forgive my ignorance on this topic. I purchased a Lawn Solutions 9 hp power seeder and I like it very much, but I am just starting out with this service. How deep do you set your powerseeder, (if you have one), to plant new seed, and how thick is the compost covering that you put down over it? I will be doing numerous powerseeding applications for customers in the spring clean ups. The ground is starting to warm up in April when I do most of the spring clean ups. Our temps here in Northern NJ at that time are usually in the mid to high 60's low 70's. I have always put down a crabgrass pre emergent in the spring clean ups, but I have to tell you, crabgrass seems to manage to pop its ungly heads on some lawns anyway. I am thinking I may not even apply crabgrass pre emerg. this spring and do the powerseeding with a starter fertilizer on the lawn I do the seeding, and apply pre emergent to the lawns I do not seed. I buy the crab pre-emerg. with fertilizer added to it. What do you suggest? Thank you.

Barefoot James
02-27-2009, 08:09 PM
Use a finished compost - peat would be way too expensive. You should be able to find a good source of compost for $15 to $30 per yard and blow it out of a wheel barrel with a back pack blower and cover 5K to 6K per yard of compost - you only need a light dusting to have a dramatic effect. You will get dirty and you do need a powerful blower - try to stay up wind and a helper to move the wheel barrel will speed up this process big time. I can spray out a yard with helper in under an hour.

If seeding in spring you will need to use Tupersan so the grass can germinate and crab grass not. It cost about $90 for 4 lbs of Tupersan and you need about 2.5 oz per 1000 sq ft - so it costs about $2 per 1000 for Tupersan and it only lasts about 30 days and you will need to reapply if all seed has not germinated or if it has germinated apply regular pre-emergent. Tupersan is a powder and needs to be mixed and sprayed.

If you don't (use tupersan) and you say you have lots of crab on a known property then by June all you will have is crab as the crab will outcompete the grass.

I have a 9 hp Turf Revitilaizer (should call it money maker - or they only piece of equipment in your tool box that can truely transform lawns). I set the depth a few notches behind mid way and when tines get worn about midway. whe you get past that to get cuttng into dirt or turf you probably ned to get some new tines. make sure the grass you are powerseeding is cut as short as you can - even scalped - if possiable.

Fall is the best time to seed - BTW.

Good Luck.

02-27-2009, 08:48 PM
scotts also puts out a product that gives you the 3 month crabgrass control and you can lay seed down at the same time and it will germinate. I used it last year for my lawn it worked very well

Barefoot James
02-27-2009, 09:07 PM
Really? Never heard of it. Cost?

02-27-2009, 09:42 PM
james the price varies from one store to another, i just chose this site because it has a good writeup on it. Also im not sure how accurate the prices on the web are in terms of fertilizer prices are since they have come down a good bit since last summer


Barefoot James
02-27-2009, 10:11 PM
$14 per 1000 vs. $2 - WOW. Of course it has some ferts but WOW BIG difference. Go with the Tupersan. Even 3 months worth would cost $6 vs $14.

02-27-2009, 10:16 PM
yea its exspensive, but i just wanted to throw that it was out their the product. Doesnt tuperspan have to be reapplied though like every 30 days? Im not that familiar with tuperspan.

Jason Rose
02-27-2009, 10:45 PM
I don't think most average people will have access to the type of Tupersan Barefoot was talking about. I think he's referring to a wetable powder that you would mix with water. You would probably have to buy it in a larger quantity?

The Tupersan I was refering too was more like the Scotts product, with starter fertilizer, in granular form. Hi-Yield is about the only brand I'm fimiliar with. It runs around $55 a bag for 5,000 sq. ft.

The Scotts brand AI. is Siduron I believe. Unsure if it really gives 90 days of preemergence or not.

Here's how to time it and only have to make ONE application of the expensive Tupersan.

Seed ASAP. Apply straight starter fertilizer.
When the soil temps get to where crab may start emerging (or around the latest you can get away with applying pre emergents) put down the application of Tupersan.
By this time you will hopefully already have grass coming up.
30 days after the Tupersan application your turf should be up and haven been mowed a couple times.
Now you can apply Dimension with fertilizer, for preemergence control throughout the rest of the summer.

Barefoot James
02-27-2009, 11:23 PM
4 lb bag (smallest bag they have) of tupersan is $90 or under. 4 to 7 lbs per acre - most operate in the mid range - too much will hurt germination - too little no protection - very little pre is in this stuff anyways. Any lesco (JD) or local feed/seed store carries it. Made by Gordons.

Timing is everything I was tryng to help the guy based on when HE said he was going to seed. If it was me the seed would already be on the ground and hopefully I would have 6 to eight weeks to get the seed to germinate before my crabgrass drop dead date which here in Louisville, KY is April 20th. Worst case I would do another app of seed the first week of April and get some Tupersan down on the 20th and some barricade or dimension down by May 15th.

Exact Rototilling
02-28-2009, 10:38 PM
Use a finished compost - peat would be way too expensive. You should be able to find a good source of compost for $15 to $30 per yard and blow it out of a wheel barrel with a back pack blower and cover 5K to 6K per yard of compost - you only need a light dusting to have a dramatic effect. You will get dirty and you do need a powerful blower - try to stay up wind and a helper to move the wheel barrel will speed up this process big time. I can spray out a yard with helper in under an hour.....snip....
Barefoot James,

Great tip on the back pack blower - that never occurred to me. I did a few top dressing and over seeds the hard way with a grain shovel last year.

How do you feel about compost that is derived from sewage treatment plants for top dressing?

Barefoot James
02-28-2009, 11:02 PM
Bio solids have a place but they would be tested to make sure they are safe. I would use regular compost from lawn/tree waste or fortified properly composted horse poo/bedding compost - that has been tested.