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a reliable 'lime' calculator? help :)

Posted by gardeningwithlcgrace NE PA ( on
Tue, Apr 22, 08 at 11:49

I just can't seem to wrap my head around this calculation and I'm getting different answers using online "lime" calculators for my yard.

We're working on the front lawn only. We're estimating it to be about 7500 sq ft. Our soil test indicates our ph to be 5.8 and is recommending 110 lb/1000 sq ft. Since this exceeds the "100lb/1000sq ft" rule, we'll be liming in the fall as well.

Here's what I just can't seem to figure out....(soooo blonde today!)

needing 100 lb per sq ft and I have 7500 sq ft of lawn....and the lime comes in 40 lb bags. How many bags do I need to get?

Or, what info am I missing? I feel like I"m having a mental block sitting at my desk at school. So, here I am, raising my hand....I've got a question.

Who can help?? Thanks!

Follow-Up Postings:

RE: a reliable 'lime' calculator? help :)

If your sure its 100lb per sq ft, you would need to buy 188 bags of lime. Seems like a lot. Maybe I'm wrong

RE: a reliable 'lime' calculator? help :)

If you have 7500 sq feet and you need 100lb / 1000 sq feet, you need 750 pounds of lime / 40 pounds per bag = 19 bags.

RE: a reliable 'lime' calculator? help :)

Seems like 100# per 1000 sq/ft is a bit much at one time. I thought 50# was the limit? Anyway, why not try 1/2 now then retest in the fall before applying the other half? You may find that you do not need that much lime to bring the PH to neutral or whatever your grass type desires the PH to be. It is just as bad having a high PH as having a low PH.

If it were me, I would try 50# per 1000 sq/ft now (10 bags). Retest in September and go from there.

just my 2 cents.

RE: a reliable 'lime' calculator? help :)

According to my info, 100lb per 1000 sq ft is the "limit". It does seem like an awful lot. I've been told to lime in the fall as well. Maybe the 1/2 now, 1/2 later approach would be the best.

That does seem like an awful lot of lime. I'm glad is cheap!! Thanks! LC Grace

RE: a reliable 'lime' calculator? help :)

I believe the max you are supposed to put down at any 1 time is 50LB per 1000 so you should divide 1000 into 7500 and you get 7.5 bags if it were 50 LB bags. If you are using 40 LB bags just use 10 bags.

And try not to use the powder. It will just end up on your pant legs, sneakers,fence and much of it will just blow away. Use the pellets.

Lime will only sink in about 1 inch per year. To help it, aerate in the fall and put down another 10 bags after that.

RE: a reliable 'lime' calculator? help :)

Powder is almost impossible.

Plus it's also bad to breath in. I believe Limestone dust is a carcinogen?

RE: a reliable 'lime' calculator? help :)

Yes, split it in half, since you're doing it twice anyhow. I have heard 60lbs is the limit, then you can do the second half one month later.

RE: a reliable 'lime' calculator? help :)

diyourselfer - makes sense...finally!! We were told that it would take 1-2 yrs before we really saw full benefit from the lime.

We've finally got some spring rain in the forecast. I think it'll be a busy weekend. Thanks so much!!

RE: a reliable 'lime' calculator? help :)

One suggestion is to look for lime that will pass a 100 screen. That's a bit faster to react as the pieces are smaller and the surface area is very great in comparison to their volume. Usually that's a percentage--the tiny amount of dolomitic limestone I just put down had, if I remember, 75% passing the 100 screen.

It can be a bit more expensive, so if the cost would be prohibitive for you just get the cheap stuff. ;-) It takes longer (large-screen stuff can take 3 years to react) but costs a lot less. Your soil test should also tell you if you should use dolomitic limestone (with a high level of magnesium) or whether good ol' limestone (calcium, but no Mg) is good enough.

If you don't know, don't worry about it. However, excessive magnesium can cause clay soils to compact harder than they were before.

5.8 pH is low, but not extremely so. Working on it is a good idea. Having a bit of a panic is unnecessary. 'Round here, I'm used to seeing 5.4 or so, and the grass still grows. Using organic methods, I just reagent tested my soil at a pH of 6.9.

Overadjusting your pH is as bad as letting it low. Put down half that and retest in a few months (say, August or so). Then see where you stand.

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