Weeds, moss, other grass in tall fescue backyard

Discussion in 'Homeowner Assistance Forum' started by mailforbiz, Sep 19, 2007.

  1. mailforbiz

    mailforbiz LawnSite Member
    Messages: 3

    Hi all

    My lawn is slightly over 2 years old...they put sod in the front and contractor seeds in the backyard. The sod has done well but the backyard has suffered. I had done something the first year which possibly could be a blunder - following "advice" of an overeager Home Depot employee, I had put in Rye grass in late fall two years ago in bare spots in my tall fescue (according to her such blending is more desirable ). Well, my backyard has had a patchy look ever since with bare spots all over. Recently, I also found some moss in many spots and there are two or three kinds of weeds that have sprung up. Also, I found patches where there was centipede grass growing. I don't know where that came from. I have also noticed that water tends to collect and sit rather than be absorbed as it does in the front. Well, at least part of this points to soil compaction problem so I am planning to aerate the whole backyard in couple weeks.

    So here are my questions before I aerate and overseed:

    1. Is there anything I should do about the moss?
    2. I spent a day last week pulling out most of the weeds from the root. Should I do any other treatment pre-aeration?
    3. Is there a way out of the Rye-fescue combination? I did try to clean out the rye clumps but there are still quite a few left.
    4. I have some thatch buildup in the front sod (its been a nasty summer down here in Southeast). Should I just rake it or do something else?

    Thanks a lot in advance for your advice!
  2. topsites

    topsites LawnSite Fanatic
    Messages: 21,652

    1) First thing I would do is dump about 40 pounds lime / k.sq.ft., you might also dump that concentration of gypsum if the soil is clay-based or hard packed. If that is all you do, this is likely to be pretty effective, it takes 6 months or so for this to take hold.
    It's catch-22, if at this point you do nothing else then the treatment will give you a short boost and leave your lawn ready for next fall BUT it will look like crap until then... If you do everything else then it helps, but it will need further treatment.

    2) NO, you can not treat weeds within 30 days of seeding, before or after.

    3) Keep aerating and seeding with fescue, every year, 50 pounds per 1/4 acre.

    4) Aerating should take care of this, but...

    I see too many homeowners simply aerate and nothing else...
    The next few aerate and seed, and that is all...

    Some do a little more, but what I'm talking about here is half-measures always yield crappy results, either do it right or do nothing, you're as well off but to do it right one has to follow recommended guidelines.

    For a real good treatment, something that bring your lawn to some kind of a standard, first a consistent maintenance program is needed, second the following measures are used:

    - Core aerate when the soil is thoroughly moist: AFTER it rains!
    - Dump 50 pounds of seed per 1/4 acre, that's 200 lbs. per acre, any less is a waste of time.
    - Add 40-50 pounds starter fertilizer @30% phosporus per 1/4 acre, that's 14-28-10 or so, one bag per 1/4 acre.
    - Dump 3-4 bags of lime per 1/4 acre, 40 or 50 pound bags (in your case more, a lot more, closer to 8 per 1/4 acre).
    - And, 3-4 bags of gypsum per 1/4 acre IF the soil is clay based or hard packed.
    You're probably looking at spending some MONEY, maybe $200 per 1/4 acre DIY, not sure, depends, but thereabouts.

    Now that take care of most of that moss and weeds and thatch and crap, but in late spring before the temps get TOO hot you want to follow up with a weed treatment, then just got to stay on top of it, probably have to do all of the above again next fall, probably every year if you want a LAWN. Now, once you got a LAWN you might can skip a year but it will start to go bad again, all depends what you want but once you really get it going you will thank yourself.

    Cut the grass frequently and sharpen the blades every 4-6 cuts, don't let it get too tall or you need to start bagging...

    Consistent maintenance is the key.
  3. Newt*

    Newt* LawnSite Member
    Messages: 182

    Great advice from Topsites. The only thing I would do differently is to use 1/4" of compost instead of the gypsum or in addition to depending on your budget. That will help to add organic matter and good microbes to the soil and help improve the texture.

  4. CharlotteOutdoorImpact

    CharlotteOutdoorImpact LawnSite Senior Member
    Messages: 252

    isnt the gypsum there to help with the compact clay? I think I have read about that somewhere.
  5. mailforbiz

    mailforbiz LawnSite Member
    Messages: 3

    Thanks folks for your suggestions...especially tip about using gypsum or compost. topsites your comrehensive reply is immensely helpful for relative layman like me . I'll find out if the place I usually use for mulch has compost or not. Any suggestions in that regard? Some folks advised me about putting some topsoil also. Is that useful? Also, is the fertilizer, lime, gypsum treatment to be done immediately one after another or can it be spread over some days and is the order important?

  6. Newt*

    Newt* LawnSite Member
    Messages: 182

    Mailforbiz, my thinking is you already have soil so why bring in more? Besides, bringing in topsoil runs the risk of bringing in weed seeds. Compost is decomposed organic matter and will improve the soil that you already have. It gets heated enough in the decomposition process to kill most all weed seeds.

    You might find this helpful about gypsum.

  7. topsites

    topsites LawnSite Fanatic
    Messages: 21,652

    Gypsum (aka clay buster) does a lot of things, other than bust clay.
    First it provides calcium for the lawn, however, unlike lime which is calcium carbonate, the gypsum contains calcium sulfate dihydrate... Basically, to the lawn calcium is calcium, but gypsum's calcium doesn't affect the ph (whereas lime does), and every lawn needs calcium.

    Beyond that it does help break up clay, but it also helps break up hard packed soils, what it does here in effect is INCREASE the soil's ability to retain water. It may sound like a bad thing, but in cases where moss is an issue, believe it or not that is so because the soil is incapable of soaking up the water properly (usually due to it being packed)... Once it is softened up, it helps somewhat control the moss, also the lawn is able to take better hold AND it has more water available (read: a true lawn needs a LOT of water).

    You really can't go wrong with gypsum, I've dumped 8-10 bags on a 1/4 acre before, it will not hurt it but Gypsum by itself, in quantity, usually gives a deficient lawn a boost... It's not a fertilizer, it shouldn't boost it but it's actually a side effect, the inevitable result of a beneficial soil treatment is the lawn reacts... Now beyond that it does take 6 months for the effect to truly wear through, meaning if you have clay you can expect little immediate change in the color of the soil.

    One bonus to gypsum (especially with clay) the effects are cumulative: Once that clay is gone, it's usually gone for good.

    In many ways it's like a lime, you just can't go wrong with it, it's good stuff.
    Little bit pricier than Lime, about 5-6 a bag.
    Can be hard to find, HD usually carries it but not all stores do.

    The fert AND lime needs to go down with the seed!
    Preferably right before OR after aerating, doesn't matter much but right away.
    Gypsum in and of itself, anytime, but might as well do it then.

    The lime helps keep the ph balanced from the fertilizer, otherwise the magnesium also helps immediately release some inactive ingredients in the fertilizer, in short, lime roughly doubles the fertilizer's effect: At a cost of $25 a bag of fert and $3.59 a bag of lime, it makes sense to spend $15 more for 3-4 bags of lime, keep the ph balanced and all that, even if the ph is off, at least it gets no worse.

    Gypsum is the same way, it's all part of a balanced nutrition type of a system, yes, for the lawn. That's the thing, first the soil has to have the ingredients for lawn to grow, fertilizer is great but in and of itself it is (almost) a waste... Plants need, much like we do, nutrients, and it sounds funny but almost like a food pyramid, we want a balanced ecosystem (ok that's a bit far but).

    My attitude is to have a great lawn first treat the soil.
    It's all in the soil, it really is, we tend to focus on the green stuff but it's the brown stuff underneath that has to be right.
    Because once the soil is right, a great lawn is the inevitable end result.

    Anyhow, best of luck, I think you're on track.
  8. topsites

    topsites LawnSite Fanatic
    Messages: 21,652

    Oh I just remember, moss...

    Moss makes its appearance due to any one or some or all of these:
    1) Constant shade, moss almost never grows in a full sun area, it can't.
    2) A low soil ph.
    3) A constant presence of moisture, water in soil that never quite dries out.

    Usually moss grows near trees, it's one of those things, the tree likes and contributes to low soil ph, the tree provides shade, and then if the soil is right the water sticks around.

    That's the problem with soil compaction is the water can't drain down towards the roots of plants. It stays near the top most level, keeping the entire area humid, and this is how moss happens.

    Seeding helps in that once lawn gets going, it helps soak up moisture.
    Lime helps by raising the ph.
    Gypsum helps by softening the soil, ditto for aeration, these two factors allow the water to penetrate deeper, instead of getting trapped near the surface.

    Anyhow, the one thing that also contributes to moss is watering in the evening. The problem is that water stays the whole night, so if you have been or ever catch yourself wanting to water in the evening, a simple preventative measure is to water early in the morning (4am to 7am are good starting times, watering should be completed by 8 or 9 at the latest, it does need some time before the sun evaporates it).

    Anyhow, the whole secret is to have a plan, put it into action and keep on it.
    Now I didn't want to say this earlier, but truthfully it doesn't matter but so much what you put down when, the thing is you HAVE to do it. If you want to put down lime this month, gypsum the next, and so on, if all you do is put something down every month then that is a plan also... Me, I like dealing with it once or twice a year and I am through, all this is entirely up to you.

    But you have to do it, procrastinate or laze out and it's over, so that's why I'm like do it all now and be done for a bit.
    Either way thou.

    Just thought I'd mention this.
  9. mailforbiz

    mailforbiz LawnSite Member
    Messages: 3

    Thanks guys for the helpful tips...I've been doing things haphazardly last couple of years. I wish I'd joined this forum back then - you folks are great. With two kids and with wife going to school, I only have a small window of opportunity to do this right but I'm going to give it a shot.

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