Hi,

I was wondering... Would there be any harm in adding Mg to green up the lawn (deficient or not) ? What's the rate?

Just wondering....

Thanks,
J

I would think you should only add it if you're deficient in it. I'm sure there are others who know more about it than I. I'm just going by the general approach that you only add something if it's needed.

Take it from me who has too much Mg in his soil (naturally). It's no picnic. I'll be lucky if my soil pH ever gets below 7.0, and the soil is "tight" (i.e., feels like cement when it's dry). If you have a soil test and you are not deficient, don't add any. If you don;t have a soil test, get one first. My friendly 2 cents

+1 Above.

That having been said, if you want to experiment in a smaller area by adding perhaps 1/2 oz Epsom salts or less per thousand square feet sprayed to the lawn, go ahead. If it greens up well, it's an indication that something is awry in the magnesium department.

That doesn't necessarily mean you need magnesium. Your pH could be off...

On rare occasion, perhaps once or twice a year, I use a tiny amount of Epsom salt in my iron spray. Far less than the 1/2 oz per K, actually, to enhance the green a little bit. I don't have a low Mg soil (quite the opposite) but this is enough to supply the required Mg for chlorophyll production instantly. I've been using the same three pound bag of Epsom salt for long enough that the company logo on it is from a company that went out of business years ago...

+1 on the +1. If it works, then you must have a deficiency - otherwise it would have gotten the Mg from the soil. It's way better to fix a problem than to put a band-aid on it.

OK, thanks y'all.

I am messing around with Epsom salts on our crape myrtles. Diagnosis from the crape myrtle guy was that it was not getting enough iron...or maybe magnesium. Well in pure calcium soils, could be either. I know - only a soil test will tell. However I scattered a heaping handful around the root zone of each one and watched. The area where I applied is moister than the surrounding soil and teaming with pill bugs. I haven't seen a pill bug in the yard in years. After a month the crape myrtles don't look any better.

If the Crape Myrtles are really important to you, the right step is not a soil test, but a tissue analysis. I've seen people put down Iron when Iron was really an antagonist in the situation.

Crape myrtles still don't look any better after a second app of Mg. At the same time as the first app I scattered some Epsom salts in a certain spot in the lawn. That 10x10 area is now the yellowest area in the yard. Guess a shortage of Mg was not problem.

Then that isn't it. Are you considering the tissue test? I'm wondering if it isn't a boron deficiency lit off by your soil pH, but only a tissue test would tell you for sure (and I won't recommend adding boron at any time without some kind of testing...)

Magnesium is a potassium antagonist (and calcium, but that should be in ample supply in your soil). That could be the issue as well and explain the discoloration when adding it to the lawn. It's competing with the ion pumps for space and the Mg is winning because there's too much of it.