Lime (soil amendment)

Most of us know that lime is used to raise the PH of soil (make it less acidic or more alkaline if something goes wrong). Other things Lime is used for is to loosen and lighten heavy clay soils, to free up trace elements (like boron, manganese, and molybdenum) and locks up aluminum and other heavy metals often found in heavy soils.

Slaked Lime or Quick Lime is a fast acting inorganic PH adjuster that must be applied every year or two. Slaked lime is not lime at all but rather Calcium Hydroxide...shells or bones washed in hydochloric acid and pulverized into a powder.

Ag lime (what I recommend) lasts for years, adjusts PH only to the point of being neutral (7.0 PH) and is nothing more than limestone ground up into a fine sand like consistency. So it is 100% organic. (Here after all lime comments will refer to only AG Lime)

With heavily compacted clay soils merely adding sand to the top 6 or 8 inches will not loosen the soil, will not improve drainage, and will not improve the soil structure. In fact merely adding sand will make a primitive brick when it gets sun baked. The proper treatment of heavily compacted clay soils is to either double dig (to 27 inches deep) the area to be planted (for small garden areas) or to use a sub soiler plow to loosen the soil to a depth that promotes root growth, and aerates the soil to improve water absorption and retention. Once the soil is loosened an application of lime will cause the small clay particles to bind together forming larger soil particles and maintains the aeration and water retention qualities. Adding humus to this mix only improves the soil structure further and has the added benefit of adding nutrients back to the soil. In a raised bed situation, where you only have 8 or 10 inches of soil, or other growing media, consider loosening the soil beneath the bed...some vegetable roots extend 6 feet deep. While you're there consider adding some lime and mixing the growing media of the bed into the top two or three inches of the soil. This will help during drought periods and lessen watering requirements over all, due to the roots being able to grow deeper into the soil to get water.

Typical application rates of lime run from 2 to 4 tons per acre. Sounds like a lot doesn't it, but here are a few garden sized equivalents and how to figure it out.

Lets start with two of my garden spots. One, my primary garden spot (PG), is 30' x 40' or 1,200 sq ft. My "corn patch" (cp) is also 1,200 sq ft (60' x 20'). To apply 2 ton per acre equivalent lime to these spots first we need to know how many square feet there are in 1 acre. There are 43,560 square feet in 1 Acre. 1,200 square feet = 0.0275482 Acre So take the 4 ton application rate convert that to pounds...4 x 2,000 = 8,000 then multiply that by the number of acres 8,000 x 0.0275482 = 220 pounds of lime...about 6 40 pound bags (240 pounds actual) . The 2 ton rate would be 110 pounds or about 3 40 pound bags (120 pounds actual). At a cost of $3.00 per bag even the heaviest application would cost less than $20.00

Here are a few small garden sizes for reference (4 ton rate)

200 sq ft..................0.00459 Ac ................ 36#
300 sq ft..................0.00689 Ac ................ 55#
400 sq ft..................0.00918 Ac ................ 73#
500 sq ft..................0.01147 Ac ................ 92#
600 sq ft..................0.01377 Ac ................ 110#
700 sq ft..................0.01607 Ac ................ 129#
800 sq ft..................0.01836 Ac ................ 147#
900 sq ft..................0.02066 Ac ................ 165#

1,000 sq ft................0.02295 Ac ............... 184#
1,500 sq ft................0.03444 Ac ............... 275#
2,000 sq ft................0.04591 Ac................ 367#

If you have a sandy soil you would not need but half the lime required for a heavier clay soil, but should add twice the humus compared to a clay soil.
As always do not just add lime (or any soil amendment) without knowing what the soil actually needs. If the soil is not acidic do not add lime.

We bought 50# of lime to use in neutralizing odors in the stalls.  Would this be the Ag lime?  We've never used it in our garden areas before, only in the fields when we planted oats and hay years ago.   It's probably not too late to do that even though we have a bit of snow on the ground? We have heavy clay soil but the raised bed gardens have been amended with old manure and topsoil.