12d65980_ening_Tips_and_Plants___How_to__Plant_Symptoms
[Deficiency] Magnesium [Plant Uses] Chlorophyll; aids in carbohydrate metabolism, energy use, and genetic material manufacture [Sources] Kelp or fish extract, mulch dolomitic limestone, compost [Plant Symptoms] 
Leaves are thin and brittle; purplish red or brown to bronze; striped or yellow to brown between veins; curl upward; or don't grow long Plants mature late and don't thrive
Organic Gardening Tips and Plants - How to