Hi,

I have a lawn of centipede in NC that's about 1.25 years old. One side of the house is relatively weed free, and the other side has weeds such as (I believe) poa annua, florida betony, wild onion, carolina geranium, dandelion? and maybe some more I haven't identified.

I've been trying to get a healthy stand of grass as a first line of defense...still working on that. I haven't put any herbicides on the grass but am now considering to do so.

I'd like to start using a pre-emergent. I realize that I probably should have applied some back in October/November. Now I'm planning to maybe use some barricade/prodiamine in late February/early March and then again in Oct/Nov of this year.

I'd also like to try using a post-emergent herbicide to control the weeds that are there already. I'd appreciate it if you'd entertain a few questions:

1- Does my plan of using pre-emergents sound ok? I was thinking the barricade/prodiamine since it sounds like it lasts fairly long. I assume they'll have an application rate for centipede on the label?

2- I was thinking of using barricade 0-0-7 0.38% barricade as I saw it online for $13 for a 20lb granular bag (I prefer granules if possible). Another option I saw but haven't researched were stonewall. Will using the 0-0-7 in Feb/March mess anything up (I didn't think so since it doesn't have Nitrogen)?

3- Is it ok to spray Image for centipede (atrazine) as a post emergent right now while the centipede is dormant and within a month or so of using a preemergent?

I really appreciate any information or tips you can give!

thanks

Just out of curiosity, how are you caring for the centipede? Watering? Mowing? Fertilizing?

thanks guys...I am trying to follow best practices when watering, mowing and fertilizing. In the spring/summer I do one deep watering once per week using my irrigation. I mow weekly during the growing season, and I fertilized twice last year using fairly low nitrogen with recommendations from my soil report (I used 3lbs per 1,000 ft2 of 15-0-15).

I do have a problem with the ph, which I've discussed on this board before. With centipede liking a low ph, I have a high ph between 7.5 to 8.0. Last season I used two applications of sulfur granules and it lowered it a bit...so I'll just have to keep trying to lower it gradually. I believe that is part of the reason I have some weeds on one side of the house. My lawn is also beside a large "pasture" which is full of weeds.

mrshanno wrote:I do have a problem with the ph, which I've discussed on this board before. With centipede liking a low ph, I have a high ph between 7.5 to 8.0.

There is your problem. You will never get Centiweed to grow worth a flip in alkaline soil. It thrives at 5.4-5.8 and almost impossible at 6.5 and higher. There is no amount of sulfur you can add to get that low. Time to switch to either Saint Augustine, Zoysia, or Bermuda.

Centiweed is a niche grass to be used where there is abundant rainfall, soil is nutrient poor, and extremely acidic soil where nothing else will grow except Centiweed and Blue Berries.

Sorry to be so cynical, but dude quit working against Mother Nature as you will never win that battle. Work with her, not against her.

I can appreciate the advice texasweed...if I had tested the soil before centipede sod I certainly would have used another variety of grass. With that said, I plan on trying to lower the ph and only go to another grass variety if the grass fails completely. If I go that route, I'll be asking advice on the easiest way to move from centipede to another variety.

So far though, a great majority of the yard is doing very well despite the ph and weeds on one side of the house (no iron chlorosis yet, crossing fingers).

I used two applications of 3 lbs of sulfur granules (per 1,000 ft2) last year, and 6 months when tested again the ph moved downward slightly:

quadrant 1 pre-sulfur ph- 7.5
quadrant 2 pre-sulfur ph- 7.8
quadrant 3 pre-sulfur ph- 7.7
quadrant 4 pre-sulfur ph- 8.0

quadrant 1 post-sulfur ph- 7.4
quadrant 1 post-sulfur ph- 7.6
quadrant 1 post-sulfur ph- 7.6
quadrant 1 post-sulfur ph- 7.7

In the meantime, any other advice on the weed control in my first post?

thanks

thanks guys, I appreciate all the responses. Please let me know if anyone else has any info.

Where in NC are you?

I would say since you already invested in the sod, go ahead and give it shot and see what happens. Depending on where you are in NC and the kind of soil you have, you may have to break up the watering to keep it watered correctly. I know down here in Fayetnam most of the soil is sandy and will not hold water for a week especially in the heat of summer. As for the Pre-M, have you checked out a John Deere Landscapes or Lesco? They have Stonewall and it is much cheaper then buying at a big box store. The reason I asked you where you live is because the more specific you are the better someone may be able to help you since different parts of the state have different soil and weather.

Your soil must be pure limestone to have a pH that high. As TW said, you are fighting Mother Nature. I believe that is the reason you are seeing weeds. If you can spray them out, fine, but watch to see if they return faster than the grass fills in. I'm thinking the grass is thinning faster than it is spreading. If that is the case, think in terms of cutting your losses. You should not have to continually apply herbicide if the grass is dense enough.

St Augustine would be fine with the high alkalinity. Half of Texas is limestone and St Aug does great. If you replaced the thinning centipede with a flat or two of St Aug, it would start to fill in for you. St Aug and centipede are cared for differently. You can favor the St Aug by fertilizing with better fertilizer in May and September (or organic any time of year and more frequently). Centipede does better when mowed at 1 inch, and St Aug does much better when mowed higher than 4 inches. If you care for the lawn like it was St Aug it would soon be all St Aug without any Herculean renovation project. St Aug will spread 10 feet in all directions per season. It has two spreading spurts - one each in the spring and fall.

Thanks guys...Im on the central coast of NC. My soil is mostly sandy loam, so I have noticed it being hard to make it a full week (watering wise) during the very hottest of the summer, but I still try to get it one deep watering per week.

The centipede is very dense in probably 80% of the yard and is doing very well. I think I didn't help matters by initially laying the sod in late November and it not having a chance to take root till the next spring.

I know it's not limestone...I heard from a neighbor that there used to be piles of concrete on the lot. I think that is a major reason for the high ph. I'm gonna try to fight it using sulfur. If I lose the battle, I'll probably let st. augustine or another fill in and take over the centipede.

In the meantime, I think I'll try the pre-emergent in late feb/early march and maybe try some spot treating with post-emergent (atrazine or roundup) now while the grass is dormant.

Michael Wise,

I have little grass to the south of the house, and none on the north side. The west side grass (which contains probably 70% of the total grass) is doing very well and doesn't have many weeds weeds relative to the east side of the house (which contains probably 20% of my total grass). The east side (worse side) has weeds and is definitely shadier as a house is closeby on that side.

As far as irrigation, actually I did do what you suggested and irrigated at times when it just started showing that it needed it (instead of watering on a weekly schedule). It probably ended up being every 5-7 days on average, maybe every 4 days at the very worst part of the summer.

thanks

simpson wrote:Feb-Mar seems a litter soon for pre M. One good trick is to watch for the forsythia bloom. Its a bright yellow bush.

This year has been so much warmer than usual, so February might be a good time to do it, depending on where he is in NC. I'm planning on putting the pre M out next week, unless something changes. I'm in eastern NC, and my soil temp has been below 50 for maybe 5-6 days since Fall. I was checking the yard yesterday, and I my Bermuda is still green in spots. It's really screwed up my plans, because I had planned to round up the winter crap, but I'm afraid to do it now because I'm not sure if the grass is completely dormant. And the way this Winter has been going, I'm not sure it ever will be.