Time to Lime

I’ve been studying soil testing for a couple of years now. Taking the test is the easy part, the hard part if figuring out what to do with the numbers you get back from the lab! I discovered that a few of our newer vegetable fields had a lower than optimum pH. The term pH refers to “the power of hydrogen”, and is matched to a scale that ranges from acidic to alkaline (1 to 14). The goal on a crop farm is neutral, or a pH of 7. It is at neutral that the greatest number of plant essential elements are in a state of chemical availability. Some of our patches were at 6.2, not far off from 7, but still in need of assistance.

The method of choice to raise the pH is to spread lime. There are two types of locally available agricultural lime – high calcium (calcium carbonate) and dolomitic (calcium magnesium carbonate). Since our magnesium levels are perfect, we chose high cal lime. The part of the lime that does the pH adjusting is the carbonate part – it releases hydrogen from the soil and allows calcium and other cations to take its place.

This is the time to call in a professional lime spreader. We ordered 2 tons per acre and needed to lime 13 acres. The complicated part is to time this operation. In order to allow a 20 ton rig to roll across a field, it needs to either be frozen solid, or dry enough that the soil won’t compact under all that weight. We ordered the lime in early February, hoping that we’d catch a good hard freeze one morning. That never happened. Instead, this strangely warm dry winter/spring gave us soil moisture levels so low that we could have the lime spread in March.

Kevin Baker came out on a cool March morning and spread the lime.

This is exciting for a farm! It’s wonderful to have someone who can do this job well for us.

Here’s what it looked like when Kevin was done.

That’s the winter cover crop of wheat and lots of finely ground limestone. Once we till that in, the carbonate can start to do it’s thing and our pH will rise toward neutral.

Finally, after waiting for perfect soil conditions for a couple of years, we had the chance to get this job done. Cheers to a perfect pH and lots of calcium to feed your vegetables!