Learn to Grow with Tommy: Epsom Salt Foliar Spray

Learn to Grow with Tommy:  Epsom Salt Foliar Spray

Detroit Nutrient Company explains how to do an Epsom Salt Foliar Spray to add Magnesium to plants under LED lights at the leaf surface where it is most beneficial.

See below for a video transcript.

on today's edition of helpful tips with Detroit Tommy

the epsom salt foliar spray


“hey everybody,

Detroit Tommy here!  We're going to do a quick foliar spray for you. I've been promising to show you how I do it and now we're going to do it in the new grow space here.  

We've got the command series from agromax and we've got our auto pots set up. We're going to try this on some Han Solo Burgers and some Wedding Pie we have going on here in the room . 

So, we normally do two tablespoons to a gallon so I am going to do a half a tablespoon to one quart in my quart spray container.  Now we're doing this right before our lights go off so you got to remember that you want to do it right before "lights off"  -- because you don't want to burn little spray holes in your plant leaf surfaces.

We're going to pump this up right here: shake, shake, shake, shake, shake, shake, shake, shake, shake, shake, shake.  If you are in soil and you're using led lights: the led light is cooler so your leaf set to your leaf temperature is a little bit cooler. That causes a lower perspiration rate, making your magnesium, potassium, and calcium ions less mobile.

In that three-way competition the magnesium ion normally loses out.  So if you were to just do a Calmag drench it would do no good.   It's not that the soil is depleted of magnesium.  Because of the lower surface temperature on the leaf the plant isn't sweating so it's not bringing the magnesium up.

So what we're doing is applying it right where it needs it on the plant leaf surface. We're going to go through the foliar, do the stem, through the stem, the plant leaf surface, and so on.  Then, in about 10 minutes when I'm done doing all these plants, our lights are gonna turn off for about four hours.  We're gonna give these guys a little rest and some time to dry off.

So, stay cool!  I look forward to getting back out on the road this fall and seeing everybody and doing some tea classes and can't wait to come out and shake some hands.


  • Steve

    Can the Epsom salt foliar spray be used on flowering plants?

  • Michael

    I’m just curious on what the benefit is of doing this epsom salt foliage spray? New to your soil, going to try it in a week. Researching how you do your teas for start and bloom for a run. Would be great to see and learn your soil at a seminar.

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