Magnesium deficiency in tomato plants is easily solved. Adding Epsom salt when priming the garden soil in the spring is one approach and watering with Epsom salt and water is another. The key to treatment is recognising the symptoms.
Tomato plant leaves start to yellow along the veins while the leaf margins will remain green. If the deficiency worsens the whole leaf turns yellow.
Tomatoes that suffer from magnesium deficiency suffer from stunted growth and reduced fruit production.
Mixing Epsom salt into the soil in the spring is one solution, along with placing it into the hole before planting the tomato plant. Also adding Epsom salt to the watering can once every two weeks adds magnesium to the tomato bed.