I have two variegated peace lilies, and the leaves are turning brown as well as the flowers. I transplanted them and used Miracle Gro Moisture Control potting soil. I have what is called a moisture meter that I use to check the soil for moisture, but the leaves are still turnig brown. What am I doing wrong?
Care of Variegated Peace Lily
Also, as the blooms age, they turn green than finally brown. This is normal.
The easy answer is that you are overwatering. The plant's soil is staying too wet. This is not too surprising, as research on peace lilies (not a lily at all, actually related to philodendron) will give you watering directions ranging from allow-to-wilt-between-watering to keep-moist-all-the-time. Ouch! No wonder you don't know what to do.
My advice comes from being a plant care professional in the interior landscaping industry for 30 years. I've taken care of literally thousands of spaths - that's what we call peace lilies. Here's what I learned. Most important, you need to check the soil moisture all the way to the bottom of the pot. Not just on the surface, because the roots are in the bottom. When that soil reaches a just slightly damp stage, you can water again.
You don't want the plant to routinely dry so much that it wilts, because that is stressful and unnecessary, although if spaths do dry to the wilt point, they easily recover, losing only a few leaves.
Moisture meters are notoriously unreliable, better to use a wooden skewer or dowel, and run it between your fingers to evaluate moisture content. Here's a link telling you more about soil testing http://www.youtube.com/watch?v=Tf-8InSamYQ
However, since you are using a meter, don't water until it registers in the first quarter of the dial.
Unless the plants have been in the same pot for a couple of years, you probably didn't need to repot, either; and the "moisture control" potting soil is really not the best. Professional growers and interior landscapers use what is called a "soilless mix," and you can find some if you call around to independent plant stores in your area. If you can't find that, use cactus mix, and add about a quarter volume of perlite.
I think I would advise you to take your spaths out of the MG soil, and put them into something more free-draining. Then start to let them dry more between waterings, and trim off the damaged parts of leaves to help you "read" the plant - when the leaves stop tipping, you're watering correctly.
This link will take you to a page of peace lily articles: http://www.google.com/cse?cx=012078378210706707791%3Af1h5n_k1r5e&ie=UTF-8&q=grapes&oq=&gs_l=#gsc.tab=0&gsc.q=peace%20lily%20care