I have always had probl;ems with my chard and beet leaves turning brown and...
I have always had probl;ems with my chard and beet leaves turning brown and shriveling up. we have raised beds about 3 years old. to start we made soil in 3 parts leaf compost, peat moss, and vermiculite. we do add some fertalizer. But I always get these dried brown leaves. Also we have sooooo many weeds that keep coming in. I try to pull them and get the roots, but I am worried the soil becomes "root clogged"? with weeds. Thank you for any help.
This looks like leafminer damage on the beet foliage. At this point all you can do is use the parts of the foliage that are not affected.
Next time you plant cover with row cover immediately. See our Insect profile on leafminer for prevention and control http://extension.umd.edu/growit/insects/leafminer
For Weed control try using grass clippings with no herbicides, shredded leaves, newspaper covered with straw, pulling by hand or using a hoe.